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Wolfram Fischer

Base-DRGs, Fractionation Coefficient and Treemapsfor the Assessment of theRelative Clinical Homogeneity of DRG Systems

September 2005· Last update: 30.09.2005 (v1.2)

Contents

1 Abstract 2

2 Introduction 32.1 Starting point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.2 Relative clinical homogeneity . . . . . . . . . . . . . . . . . . . . .. 3

3 Data 43.1 DRG systems taken into account . . . . . . . . . . . . . . . . . . . . . 43.2 Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4 Methods 64.1 The Definition of "base DRGs" . . . . . . . . . . . . . . . . . . . . . . 64.2 Standardisation of the major diagnostic categories . . .. . . . . . . . . 74.3 Fractionation coefficient . . . . . . . . . . . . . . . . . . . . . . . . .84.4 Treemaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

5 Results 105.1 Number of base groups and number of case groups . . . . . . . . .. . 105.2 Fractionation coefficients in pair comparisons of DRG systems . . . . . 135.3 Fractionation coefficients according to major diagnosic subcategory types 155.4 Fractionation coefficients according to major diagnosic subcategories . 155.5 Major diagnostic subcategories with more problems and with fewer

problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.6 Example of a treemap for the display of fractionation coefficients . . . . 215.7 Example of a treemap for the comparison of two DRG systems. . . . . 245.8 Examples of individual DRG-related evaluations . . . . . .. . . . . . 26

6 Discussion and prospects 31

7 Appendix 337.1 Table of abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . 337.2 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

30.09.2005 (v1.2) 1

Wolfram Fischer· Base DRGs, Fractionation Coefficient, and Treemaps

1 Abstract

This study complements the customary statistical homogeneity analyses (i. e. the Introductioncomputation of achievable variance reduction and the remaining dispersion withinDRGs) by means of a comparison of DRG systems on the level of base DRGs.

The study is based on 900,000 records from Swiss hospitals from the years 2000 to Data2003. The records were selected according to quality criteria.

Pair comparisons were conducted to try to compute the divergence in the assignment Methodof base DRGs of the AP-DRG, APR-DRG, AR-DRG, IR-DRG systems among eachother, and for individual evaluations also according to SQLape, LDF and CCS, and torepresent the results graphically. For this purpose, a so-called "fractionation coefficient"was developed. Visualisation was effected on the basis of treemaps.

The study yielded the following results: the actual DRG systems (AP, APR, AR, IR) Resultspartially display similar grouping concepts in the medicalsphere. In this respect, thegreatest similarities exist between AP and APR, and betweenIR and APR. In the sur-gical sphere, AP and, to a lesser extent, AR were found to havesome common featureswith APR; apart from this, it became apparent that the surgical base DRGs are morediverse in their make-up than medical base DRGs. The most conspicuous differenceswere discovered between the surgical base IR DRGs and the surgical base DRGs of theother DRG systems.

In order to be able to compare the SQLape categories with the base DRGs in spite ofthe differing construction approach, the SQLape code of themain treatment was estab-lished for each individual hospital case. In addition, someanalyses were also conductedwith the help of the primary SQLape codes computed by the manufacturer. Correspon-dence with the other systems was relatively low. However, the different perspective alsocan serve to detect deficiencies in the DRG systems.

In comparison with the CCS classification, which is also based on a diverging con-cept, all the systems showed great differences, with the surgical SQLape main treatmentcategories being the exception.

The definitions of a great number of base DRGs are distinctly different in the systems Conclusionsunder scrutiny. With regard to the choice of a DRG system, this means that it is notmerely a licenser and a cooperation model that are chosen, but at the same time also acertain way of viewing clinical treatment.

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2 Introduction

2.1 Starting point

One of the tasks of the SwissDRG project1 is to select a national DRG system forA DRG system forSwitzerland Switzerland. It is to be expected that the first step will consist in making an existing

system compatible with the coding systems used in Switzerland. Subsequently, the sys-tem will be subjected to adaptation and corrections with a view to making it usable inSwitzerland.

It is necessary that both the selection of, and any later modifications to, such a sys-System assessmenttem should be based not only on economic calculations but also on substantial clinicalanalyses.

In view of the system selection, SwissDRG commissioned the Zentrum für Infor-Commissionmatik und wirtschaftliche Medizin (ZIM) to compare selected DRG systems (APR-DRG, AR-DRG, IR-DRG; SQLape) on the basis of the base DRGs. The study thusconducted2 was then extended by ZIM. This paper presents the state of thework doneto date.

2.2 Relative clinical homogeneity

Examinations of DRG systems usually apply statistical homogeneity analyses, suchEconomic homogeneityas the computation of variance reduction in respect of length of stay or of costs, or thecalculation of the remaining dispersion of these variableswithin DRGs. Calculations ofthis type serve to examine economic homogeneity: the dependent variable that is meantto be explained by the DRG classification is a variable that can be or has been valued inmonetary terms. A DRG is economically homogeneous if the costs of the cases assignedto this DRG are similar.

The assessment of clinical homogeneity focuses on the question as to whether syn-Clinical homogeneitydromes and/or treatments of patients that are assigned to the same DRG, are similar.This question is less easy to answer by means of statistical methods. The measureof correspondence between existing diagnosis and/or procedure codes might be ableto provide a pointer but will remain unreliable since some codes differentiate morestrongly than others and also since hospital cases of a similar type may be representedequally correctly with differing code combinations.

As a way out of this situation, an attempt was now made, not to assess clinical ho-Relative clinicalhomogeneity mogeneity as such, but to compare the classification of hospital cases in different DRG

systems with each other. The more concordant the concentration of hospital cases inindividual DRGs, the greater the "relative clinical homogeneity".

1 http:// www.swissdrg.org /.2 Fischer [Basis-DRG-Vergleiche, 2005].

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3 Data

3.1 DRG systems taken into account

The following patient classification systems3 were examined: DRG systems

• AP-DRG-CH: All Patient Diagnosis Related Groups (Hersteller: 3M, USA).4

• APR-DRG 15: All Patient Refined Diagnosis Related Groups (3M, USA).5

• AR-DRG 5: Australian Refined Diagnosis Related Groups (Australien).6

• IR-DRG 2005: International Refined Diagnosis Related Groups (3M, USA).7

In a number of evaluations, the following additional reference systems were used: Additional systems

• SQLape 2005: Striving for Quality Level and Analysis of Patient Expenditures(Sqlape, Schweiz).8

• LDF 2005: Leistungsbezogene Diagnosen-Fallgruppen (Österreich).9

• CCS: Clinical Classification Software (USA).10

Compared to established DRG systems, the SQLape system usesa different classifica- SQLapetion concept. As in DRG systems, only one cost weight resultsfor each hospital case.Yet the SQLape system functions with a number of patient groups which is clearlylower than the number of DRGs in DRG systems, that is to say with only about 350SQLape groups compared with 640 to more than 1200 DRGs. This is possible becauseonly treatments and diseases are represented by SQLape groups but not severity de-grees. Instead of severity categories (e. g. DRGs with or without CC) more than oneSQLape group can be assigned to one hospital case. Furthermore, the main diagnosisdoes not decide the primary attribution of a DRG, but it is used the same way as allsecondary diagnoses.

All the hospital cases in the database were grouped according to the mentioned pa- Groupingtient classification systems by Hervé Guillain and Dung Duong of the CHUV (Centrehospitalier universitaire vaudois, Lausanne).

3.2 Database

The database that was used contains just over 900,000 cases from the years 2000 Data baseTable 1to 2003. There are data from the Swiss APDRG Association11 as well as the data sets

additionally made available to the SwissDRG project12 by the Swiss Federal StatisticalOffice (SFSO).

The data from the Swiss APDRG Association come from the hospitals of the CHUV AP-DRG-CH dataand individual hospitals in the Cantons of Ticino, Valais and Neuchâtel from the years2000 to 2003.

The SFSO data come from hospitals all over Switzerland from the years 2002 and SFSO data2003, with the SFSO selecting the data of those hospitals in the survey of medicalstatistics13 which satisfied the following quality criteria:14

3 Vgl. Fischer [PCS, 1997].4 APDRG-CH [CW 4.1, 2003]; 3M [AP-DRG-CH, 1998].5 http:// www.3m.com / us / healthcare / his / products / coding/ refined_drg.jhtml.6 http:// www.health.gov.au / casemix /.7 Vgl. Mullin et al. [IR-DRG, 2002].8 http:// www.sqlape.com /.9 BMGF-A [LKF05-Modell, 2004]; http:// www.bmgf.gv.at / cms/ site / themen.htm ? channel=CH0005.

10 http:// www.ahrq.gov / data / hcup / ccsicd10.htm. Vgl. auchZahnd [CCS, 2004]; Zahnd [CCS, 2003].11 http:// www.apdrgsuisse.ch /.12 http:// www.swissdrg.org /.13 BFS-CH [Medizinische Statistik, 1997].14 Schwab/Meister [CMI, 2004]: 15.

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Table 1:Data according to yearsand hospital types

Hospital type 2000 2001 2002 2003 SUMME in %From AP-DRG-CH survey 70319 56949 68593 195861 21.75K111 University hospitals 89971 95417 185388 20.59K112 Central hospitals 84790 87744 172534 19.16K121 Regional hospitals level 3 68738 81796 150534 16.72K122 Regional hospitals level 4 76776 87833 164609 18.28K123 Regional hospitals level 5 12705 12928 25633 2.85K232 Special gyn./neonat. clinics 2874 3039 5913 0.66sum 70319 56949 404447 368757 900472 100.00in % 7.81 6.32 44.92 40.95 100.00

• The case figures between medical and administrative statistics differ by no morethan 5 %.

• More than an average of 2.2 diagnoses per case are available.

The number of hospitals involved cannot be detected from thedata supplied.The mean length of stay was 8.2 days. The median was located at6 days, the first

quartile at 3, the third quartile at 10 days.15

In the SFSO data, the main procedure was already encoded as such. Since this was notSelection of the mainprocedure the case with the data from the Swiss APDRG Association, Guillain and Doung from

the CHUV determined the hospital cases for the main procedure as follows:16

1. That code was selected from among the procedure codes which would be recog-nised as an surgical code by the DRG grouper and which influences DRG assign-ment.

2. Failing that, that code was selected from the procedure codes which influencesDRG assignment.

3. Failing that, that code was selected from the procedure codes which would berecognised as an surgical code by the DRG grouper.

4. Failing that, the first existing procedure code was selected.

15 In Switzerland, length of stay is calculated by counting both the day of admission and the day of dis-charge.

16 According to an e-mail from Hervé Guillain, CHUV, dated 20 April 2005.

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4 Methods

4.1 The Definition of "base DRGs"

Base DRGs (base groups, adjacent DRGs) result from the combination of the adja-cent DRGs without splits by complications and comorbidities and/or age groups.17

The following definition would be more differentiated: in a DRG system, those pa- Proposed definitiontient groups are labelled "base DRGs" which can be distinguished according to maindiagnoses and procedures but not according to any of the following split criteria:

• CC (comorbidities and complications).

• Age.

• Type "complicating diagnosis".

• Type "complicating procedure".

• With/without death during hospital stay.

• Reason for discharge: against medical advice.

• Transfer within a given period of time.

• Possibly certain procedures (such as AP-DRG 411/422 with/without endoscopy).

• AP-MDC 15: possibly birth weight and/or significant procedures.

• AP-MDC 24: possibly with/without tuberculosis (DRGs for HIV patients).

• AP-MDC 24: possibly type of associated diagnoses.

Annotations:

• In the AR-DRG system, the base DRGs are known and can be encoded. (The firstthree characters of the code designate the base AR-DRG.) In the RDRG, APR-DRG, IR-DRG, LDF, EfP (from GHM), as well as in SQLape, the base DRGsare also designated and encoded. In these systems, it would have to be examinedwhether and to what extent the predefined base DRGs fit the above definition.

• In the G-DRG system 2005, the concept of base DRGs initiallytaken over fromthe AR-DRG system was broken up for the purpose of avoiding a conflict withprocedure hierarchy.18 The base G-DRGs can still be determined; however, thisis no longer done on the strength of the G-DRG codes but on the basis of ananalysis of the G-DRG label.

• Draft lists of AP-DRGs and base AR-DRGs can be found in Fischer [DRG+Pflege,2002].19

With one single exception, the DRG systems analysed in this study already had base For this study: adoptionof the manufacturers’base DRG definitions

groups labelled by the manufacturer. For financial reasons,these base groups wereadopted without any further analysis.

Only the AP-DRG system was not equipped with a labelled list of base groups. Forthe determination of the base AP-DRGs, the data were only grouped according to maindiagnosis and main procedure. To identify the base AP-DRGs,the AP-DRG codes werepreceded by an "A-" (for "adjacent").

In order to be able to conduct 1:1 comparisons between SQLapecategories and DRGs, Determination of theSQLape category of themain treatment: "SQp"

the SQLape procedure category that the system returned whenonly the main diagno-sis and the main procedure were grouped, was used as the base group; if no SQLape

17 Fischer [DRG-Systeme, 2000]: 27, on the basis of the "adjacent DRGs" ("ADRGs") defined in the RDRGand APR-DRG systems. – Cf. Freeman JL et al. [1991]: 63 ff.

18 Cf. among others the example in Roeder et al. [G-DRG 2005 (II), 2004]: 1022 f.19 AP-DRG: Fischer [DRG+Pflege, 2002]: 327-367. AR-DRG: Fischer [DRG+Pflege, 2002]: 368-423.

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procedure category existed, use was made of the SQLape diagnosis category returned.This patient category was called "SQLape main treatment category". The abbreviation"SQp" was used.

In the course of the work done on the study, the manufacturer defined the firstPrimary SQLapecategory: "SQ1" SQLape category as the primary SQLape category, which also increased comparability

with DRG systems. It must be borne in mind, however, that in approximately 20 % of allhospital cases20, further SQLape categories are assigned besides this primary SQLapecategory. (DRG systems utilise a ranking according to degrees of severity [CC cate-gories], which is less differentiated.)

4.2 Standardisation of the major diagnostic categories

In order to have a common classification for the system comparisons, the majorCommon base of MDCsTable 2 diagnostic categories of the individual patient classification systems were numbered and

designated in a standardised manner. The major AP-DRG diagnostic categories served

20 In the data used, 18.7 % of the hospital cases were grouped with more than one SQLape category: 13.4 %of the cases were encoded with two SQLape categories, 3.1 % with three, and the remaining 1.1 % withmore than three.

Table 2:Standardised majordiagnostic categories

Code Short Label Label00’ Outpat. Outpatient Treatments01’ Nerves Nervous System02’ Eye Eye03’ ENT Ear, Nose, Mouth, and Throat04’ Respir. Respiratory System05’ Circul. Circulatory System06’ Digest. Digestive System07’ Hep+P Hepatobiliary System and Pancreas08’ MuscTs Musculoskeletal System and Connective Tissue09’ Skin Skin, Subcutaneous Tissue, and Breast10’ Endocr. Endocrine, Nutritional, and Metabolic Diseases and Disorders11’ Kidney Kidney and Urinary Tract12’ Male Male Reproductive System13’ Female Female Reproductive System14’ Birth Pregnancy, Childbirth, and Puerperium15’ Neonat. Newborns and Other Neonates16’ Blood Blood and Blood Forming Organs and Immunological Disorders17’ Neopl. Myeloproliferative Diseases and Disorders, andPoorly

Diffenerentiatad Neoplasms18’ Infect. Infectious and Parasitic Diseases19’ Mental Mental Diseases and Disorders20’ Drug Alcohol/Drug Use and Alcohol/Drug Induced OrganicMental

Disorders21’ Trauma Injuries, Poisoning, and Toxic Effect of Drugs22’ Burns Burns23’ Div.Fac Factors Influencing Health Status and Other Contacts with Health

Services24’ HIV Human Immunodeficiency Virus (HIV) Infections25’ Polytr. Multiple Significant Trauma91’ Trp+Trc Transplantations and Tracheostomies92’ Day1 Death and Transfer Within One Day99’ Error Unclassifiable

30.09.2005 (v1.2) 7


for the reference classification. The groups additionally defined by the Swiss APDRGAssociation and the groups of exceptional and unclassifiable cases were renumbered.For purposes of identification, an apostrophe (’) was placedbehind each code numberof the standardised system.

In the AR-DRG system, three major diagnostic subcategory types are defined: "sur- AR subcategory typesgical", "medical" and "others". The subcategory type "others" contains the AR-DRGswhich are derived from non operating room procedures. With regard to the commonanalysis, these AR-DRGs have been merged with the "surgical" subcategory type.

4.3 Fractionation coefficient

By way of measurement for the assessment of the fragmentation of the base groups Assessment of thefragmentation of a baseDRG

within a DRG system, a so-called "fractionation coefficient" was developed. The higherthe fractionation coefficient, the more strongly a base DRG of the "original" systemto be assessed is divided up among different base groups of the reference system. Tocompute the fractionation coefficient for each base DRGg of the original system, theproportional distribution of the cases among the base DRGsh of the reference system isdetermined. The greater these proportions, the less they contribute towards the fragmen-tation. For this reason, the differences between these proportions and 1 were calculated.These differences were then weighted and summed up. The weights used were the pro-portions themselves since the more cases were assigned to anidentical base DRGh, thehigher the relative influence of these cases on the measure offragmentation.

In mathematical terms, this looks as follows: A base DRGg from the original system fg : fractionationcoefficient per baseDRG

G is represented in the h-indexed base DRGs of the reference system H.pgh designatesthe proportion of the cases from base DRGg which were classed in base DRGsh of thereference system. The fractionation coefficient is calculated as follows:

fg|H =∑

h∈H

(1 − pgh)pgh with∑

h∈H

pgh = 1

or more simply:fg|H = 1 −

∑

h∈H

(pgh)2

A few examples may serve as explanations: ExamplesTable 3

• First example: all the cases that have been assigned to a certain base DRGg of theoriginal system are represented in one single base DRGh in the reference system.Such a 1:1 representation results in a fractionation coefficient of:f = 1 – 12 = 0.

• Second example: the cases that have been assigned to a base DRGg are repre-sented in two different base DRGsh in the reference system in proportions of90 % and 10 %. This results in a fractionation coefficient of:f = 1 – ( 0.92 + 0.12 ) = 0.18.

Distribution Nb. of groups Result Distribution Nb. of groups Result100 % 1 0.000 67, 22, 11 % 3 0.49099, 1 % 2 0.020 50, 50 % 2 0.50098, 1, 1 % 3 0.039 50, 33, 17 % 3 0.61290, 10 % 2 0.180 33, 33, 33 % 3 0.66780, 20 % 2 0.320 10, . . ., 10 % 10 0.90080, 13, 7 % 3 0.338 1, . . ., 1 % 100 0.99067, 33 % 2 0.442 0.1, . . ., 0.1 % 1000 0.999

Table 3:Calculation examplesfor fractionationcoefficients

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• Third example: the cases that have been assigned to a base DRGg are representedin three different base DRGsh in the reference system in proportions of 80 %,13 % and 7 %. This results in a fractionation coefficient of:f = 1 – ( 0.82 + 0.132 + 0.072 ) = 0.34.

• Fourth example: the cases that have been assigned to a base DRGg are representedin two different base DRGsh in the reference at a ratio of 50:50. This results in afractionation coefficient of:f = 1 – ( 0.52 + 0.52 ) = 0.5.

To assess the correspondence between the representation ofall the cases from a originalFG : Averagefractionation coefficientof a DRG system

system G and in a reference system H, a weighted average fractionation coefficient wascomputed. The case numbers n per base DRGg served as weights:

FG|H =

∑g∈G(ngfg|H)∑

g∈G ng

4.4 Treemaps

By means of the treemaps21 generated in this study, all the base DRGs of a DRGTreemaps for therepresentation of entireDRG systems

system are printed on one single page. Each box represents one base DRG. The sizeof the boxes reflects the proportion of cases it represents. In this way, it points out thequantitative relevance of the base DRGs depicted.

The first treemap variant shows the fractionation coefficient of the representation of↑ Example: Table 13 (p. 22)

each base DRG of the original system in the reference system by means of the valuesindicated and the colours of the boxes.

A second treemap variant was developed which has higher degree of differentiation:↑ Example: Table 15 (p. 25)

In the case of each base DRG, it can be seen now to which alternative base DRGs of areference classification system it has been assigned.

21 Cf. Fischer [KH-Vergleiche, 2005]: 113 ff; Shneiderman [Treemaps, 1992].

30.09.2005 (v1.2) 9


5 Results

5.1 Number of base groups and number of case groups

To compare the number of groups, the major diagnostic categories of the individual Standardisation of themajor diagnosticcategories of DRGs↑ p. 7

DRG systems were numbered and labelled in a standardised manner.

SUM

99’ Error92’ Day1

91’ Trp+Trc25’ Polytr.

24’ HIV23’ Div.Fac

22’ Burns21’ Trauma

20’ Drug19’ Mental18’ Infect.17’ Neopl.16’ Blood

15’ Neonat.14’ Birth

13’ Female12’ Male

11’ Kidney10’ Endocr.

09’ Skin08’ MuscTs07’ Hep+P06’ Digest.05’ Circul.

04’ Respir.03’ ENT02’ Eye

01’ Nerves00’ Outpat.

surgical/proc. medical

12 194 39 63 15

21 1810 11

5 521 12

5 66 58 95 29 35 77 282 54 52 51 11

73 64 11 34 52 2

3 2

156 201

48 7616 1236 2412 6084 7240 4420 2084 4820 2424 2032 3620 836 1220 2828 112

8 2016 20

8 204 44

2812 2416 4

4 1216 20

8 8

12 2

624 798357 Base groups

1422 Groups

APR15

SUM

99’ Error92’ Day191’ Trp+Trc25’ Polytr.24’ HIV23’ Div.Fac22’ Burns21’ Trauma20’ Drug19’ Mental18’ Infect.17’ Neopl.16’ Blood15’ Neonat.14’ Birth13’ Female12’ Male11’ Kidney10’ Endocr.09’ Skin08’ MuscTs07’ Hep+P06’ Digest.05’ Circul.04’ Respir.03’ ENT02’ Eye01’ Nerves00’ Outpat. surgical/proc. medical

9 2212 413 8

4 1624 1617 11

9 528 1810 710 511 8

7 511 3

5 56 82 34 51 51 9

55 53 32 6

24 29

3 3

210 189

15 3814 616 12

7 3537 3034 1818 1140 3916 1310 921 1611 815 5

8 97 183 78 103 101 12

88 104 43 10

44 2

12

3 3


665 Groups

AR5

SUM












surgical/proc. medical35

19 1716 328 618 1237 1530 914 541 1216 5

7 422 715 221 8

6 28 169 5

14 56

1 172 3

8

21 3

14

345 219

3533 5120 944 1828 3671 4548 2726 1567 3624 1513 1234 2127 635 2412 424 3215 1514 15

181 374 9

24

21 9

14


1088 Groups

IR2005

SUM


98

229

1932

933

4

13

17

3

1944

121816101311

28

10

1418

5

13

178 177

98

229

1932

933

4

13

17

3

1944

121816101311

28

10

1418

5

13


SQ2005

−50 0 50

SUM













20 347 8

14 195 12

27 181111 1927 8

2 910

14 95 5

10 10728

3813

8 17

16

1 61

8

209 230

34 7315 1630 33

8 3055 432224 4366 17

8 2215

31 219 9

18 1684

1768

198 46

35

1 91

9


883 Groups

LDF2005

−50 0 50

SUM


5 176 4

14 103 17

18 1512 10

9 522 16

9 78 67 88 5

11 35 75 102 64 71 61 8

35 63 32 73 13 29

23 2

178 193

12 308 7

20 166 37

30 2727 2016 836 2415 1610 1114 2013 814 5

9 98 264 87 152 101 8

97 143 32 105 125 3

122

3 2


649 Groups

APCH

Z I M − v1.2[DRG.AGRP.054.nGrps:c−059S]

Database: System manuals

Table 4:Number of DRGs andbase DRGs according tomajor diagnosticcategories andsubcategory types

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Table 5: Number of DRGs and base DRGs of each major diagnostic category according to the DRG system andsubcategory types

APCHLDF2005SQ2005IR2005

AR5APR15


35 35

00’ Outpat.surgical/proc. medical12 19

9 2219 17

9 1920 34

5 17

48 7615 3833 51

9 1934 7312 30

01’ Nerves

APCHLDF2005SQ2005IR2005AR5APR15 surgical/proc. medical

4 312 416 3

8 47 86 4

16 1214 620 9

8 415 16

8 7

02’ Eye


AR5APR15

surgical/proc. medical9 6

13 828 622 414 1914 10

36 2416 1244 1822 430 3320 16

03’ ENTsurgical/proc. medical

3 154 16

18 129 125 123 17

12 607 35

28 369 128 306 37

04’ Respir.


21 1824 1637 1519 1827 1818 15

84 7237 3071 4519 1855 4330 27

05’ Circul.


AR5APR15

surgical/proc. medical10 1117 1130 932 161112 10

40 4434 1848 2732 162227 20

06’ Digest.surgical/proc. medical

5 59 5

14 59 10

11 199 5

20 2018 1126 15

9 1024 4316 8

07’ Hep+P


21 1228 1841 1233 1327 822 16

84 4840 3967 3633 1366 1736 24

08’ MuscTs


AR5APR15


10 716 5

4 112 99 7

20 2416 1324 15

4 118 22

15 16

09’ Skinsurgical/proc. medical

6 510 5

7 42

108 6

24 2010 913 12

215

10 11

10’ Endocr.


8 911 822 713 814 9

7 8

32 3621 1634 2113 831 2114 20

11’ Kidney


AR5APR15

surgical/proc. medical5 27 5

15 2

5 58 5

20 811 827 6

9 913 8

12’ Malesurgical/proc. medical

9 311 321 817 1010 1011 3

36 1215 535 2417 1018 1614 5

13’ Female


5 75 56 2

75 7

20 288 9

12 4

89 9

14’ Birth


AR5APR15

surgical/proc. medical7 286 88 16

142

5 10

28 1127 18

24 3214

48 26

15’ Neonat.surgical/proc. medical

2 52 39 53 18

82 6

8 203 7

15 153 18

174 8

16’ Blood


4 54 5

14 5

384 7

16 208 10

14 15

687 15

17’ Neopl.


AR5APR15


6

131 6

8 203 10

18

192 10

18’ Infect.surgical/proc. medical

1 111 91 17

58 171 8

4 441 121 37

58 461 8

19’ Mental


75

2 3

3

288

4 9

9

20’ Drug


AR5APR15


8

165 6

12 248 10

24

357 14

21’ Traumasurgical/proc. medical

4 13 3

3 3

16 44 4

3 3

22’ Burns


1 32 6

21 313

1 62 7

4 123 10

21 913

1 92 10

23’ Div.Fac


AR5APR15


2

13 1

16 204

15 12

24’ HIVsurgical/proc. medical

2 24 2

3 2

8 84 2

5 3

25’ Polytr.


9

89

12

912

91’ Trp+Trc

−50 0 50


AR5APR15


2 2

92’ Day1

−50 0 50


3 23 3

14

3 2

12 23 3

14

3 2

99’ Error

Z I M − v1.2[DRG.AGRP.054.nGrps:s−059S]

Database: System manuals

30.09.2005 (v1.2) 11


The graphic representation of the count of DRGs and base DRGswas effected in Key to the graphsTables 4 and 5two different ways: once according to DRG systems, and once according to the DRG’s

major diagnostic categories. For the rest, both graphs havethe same structure: the lefthalf of the graph – i. e. that half in which the yellow bars are located – refers to surgi-cal/procedural DRGs, whilst the right half – that with the green bars – refers to medicalDRGs. The outer figures indicate the number of DRGs per major diagnostic subcate-gory, the inner figures the number of base DRGs. The four figures per line have beenvisualised by the bars.

A scrutiny of the graphs reveals the following striking features: Commentary

• The number of base groups differs. It ranges from approximately 360 base groups Table 4

in APR and SQLape to approximately 560 base groups in IR.

• Both the surgical and the medical subcategories within onesystem contain verydifferent numbers of patient categories.

• The number of patient categories per major diagnostic category varies greatly Table 5

among DRG systems. At least at first sight, hardly any regularities can be madeout. (One such observation would be, for instance, that: allDRG systems havemore medical than surgical DRGs within the respiratory system [04’]. But evenwhen we look at the number of base DRGs in this major diagnostic category, theIR-DRG system proves to be an exception of this rule . . . At anyrate, concerningthe musculoskeletal system [08’] there are more surgical DRGs and also morebase DRGs throughout this major diagnostic category.)

System 2 −> 1

Sys

tem

1 −

> 2

0.2 0.4 0.6 0.8

0.2

0.4

0.6

0.8

APR:AR

APR:IR

AR:IR

APR:CCS

AR:CCSIR:CCS

APR:SQp

AR:SQpIR:SQp

SQp:CCS

APR:SQ1

AR:SQ1IR:SQ1

SQ1:CCS

APR:AP

AR:AP

IR:AP

AP:SQp

AP:SQ1

AP:CCS

Z I M − v1.2[DRG.AGRP.054.plot.fraccoefs−059S]

Database: SwissDRG / Swiss Federal Statistical Office

Table 6:Map of the weightedaverage fractionationcoefficients of paircomparisons of DRGsystems

12 30.09.2005 (v1.2)

www.fischer-zim.ch

5.2 Fractionation coefficients in pair comparisons of DRG systems

The "fractionation coefficient" was developed in order to measure the extent of frag-Fractionation coefficient↑ p. 8 mentation that occurs when hospital stays are classed according to two different DRGs.

In short: a fractionation coefficient of 0 indicates a 1:1 representation. The coefficientincreases with the number of different base DRGs of the reference system that are usedto represent the cases of a base DRG of the original system to be assessed. However, itnever exceeds 1.

Table 6 illustrates fractionation coefficients for pairs ofDRG systems. A value ofTable 6

0.23 for "APR:AR" on the vertical axis, which is labelled "System 1 -> 2", meansthat when the original system 1 (here: APR) was represented in the reference system 2(here: AR), a fractionation coefficient of 0.23 was calculated for the cases contained inthe database. The assignment of DRGs corresponds better, the further to the bottom lefta pair of patient classification systems is placed.

An alternative depiction of these values is represented in Table 7, where the valuesTable 7

of the fractionation coefficients are actually printed out.In addition, these values werecoloured according to their height: blue points to low (corresponding) values, orange tohigh (diverging) values. The size of the rectangles is proportionate to the fractionationcoefficient: the smaller the symbol, the better the value.

The evaluation of the fractionation coefficients reveals that the APR and AP systemsAPR and APdisplay the highest degree of correspondence; in Table 6, the pair is placed bottom left.The comparison resulted in average fractionation coefficients of 0.1 or less. This meansthat there are many cases in DRGs that have a similar concept in both cases.

The comparison between APR and IR also yielded low fractionation coefficients.APR and IR

Table 7:Weighted averagefractionation coefficientof pair comparisons ofDRG systems

Original system

Fra

ctio

natio

n co

effic

ient

Ref

eren

ce s

yste

m

AP APR AR IR LDF SQ1 SQp

AP

APR

AR

IR

LDF

SQ1

SQp

CCS

0.23

0.15

0.12

0.1

0.26

0.32

0.51 0.46 0.43

0.6

0.49

0.56

0.51

0.56

0.42

0.24

0.73

0.67

0.68

0.67

0.7

0.59

0.64

0.55

0.48

0.5

0.52

0.53

0.48

0.57

0.53

0.75

0.70.51

0.53

0.35

0.1

0.04

0.19

0.18

0.27

0.18

0.56

0.51

0.71

0.66

0.45

0.0

0.2

0.4

0.6

0.8

1.0

Z I M − v1.2[DRG.AGRP.054.catlevelplot.fraccoefs:s:0:0−059S]


30.09.2005 (v1.2) 13


The average fractionation coefficients are below 0.12. Thismeans that here, too, thereare many cases with similar concepts in both the APR and the IRsystem.

The next pairs we look at are APR and AR, and AR and IR. Both entries are at a AR compared with APRand IRdistinctive distance from the diagonal. This means that fractionation weighs differently

depending on the direction of the representation. In concrete terms, for instance, therepresentation of APR in AR (with a value of 0.23) is worse than the representation ofAR in APR (with a value of 0.15). It is striking that the representation of IR in AR, witha value of 0.32, is the most problematic of the representations within the DRG pairs.This figure makes it evident that IR and AR are based on quite different concepts.

In the comparisons with the SQLape system, which is based on adifferent concept, SQLapethe SQLape procedure category that the system returned whenonly the main diagnosisand the main procedure were grouped, was used as the base group; if no SQLape proce-dure category existed, use was made of the SQLape diagnosis category returned. Thiscode was called "SQp". The different classification approach of the SQLape system isreflected in relatively high fractionation coefficients. They all exceed 0.42. This showsthat correspondence with conventional DRG systems is relatively small.

Even greater divergences occur when the primary SQLape categories ("SQ1") arecompared with the base DRGs of the various DRG systems. Here,the fractionationcoefficients even exceed 0.59.

The fractionation coefficients of the representation of themedical base DRGs in the CCSCCS diagnosis categories, and of the surgical base DRGs in the CCS procedure cate-gories appear in the line labelled "CCS" in Table 7. The values are high throughout;they range from 0.43 to 0.51, i. e. all the DRG systems are relatively inhomogeneouswith regard to the CCS categories. With 0.35, the LDF system does not possess a sub-stantially better value. The conspicuous exception is the representation of SQp in CCS,where the fractionation coefficient is only 0.24.

Table 8: Weighted average fractionation coefficient of pair comparisons of DRG systems according to majordiagnostic subcategory types

Original system

Fra

ctio

natio

n co

effic

ient

Ref

eren

ce s

yste

m


AP

APR

AR

IR

LDF

SQ1

SQp

CCS

0.28

0.17

0.35

0.37

0.4

0.43

0.59 0.56 0.49

0.63

0.55

0.6

0.58

0.58

0.42

0.21

0.62

0.56

0.58

0.6

0.49

0.36

0.5

0.64

0.44

0.57

0.5

0.61

0.33

0.5

0.64

0.48

0.650.58

0.49

0.46

0.09

0.03

0.23

0.21

0.37

0.35

0.59

0.56

0.58

0.58

0.55

C : surgical / proc.


AP

APR

AR

IR

LDF

SQ1

SQp

CCS

0.21

0.12

0.06

0.03

0.18

0.24

0.430.3 0.34

0.58

0.43

0.54

0.42

0.56

0.43

0.37

0.81

0.77

0.81

0.76

0.82

0.75

0.79

0.5

0.5

0.44

0.53

0.48

0.51

0.63

0.48

0.83

0.740.45

0.53

0.32

0.1

0.04

0.17

0.18

0.19

0.12

0.54

0.45

0.82

0.78

0.33

M : medical

0.0

0.2

0.4

0.6

0.8

1.0



14 30.09.2005 (v1.2)

www.fischer-zim.ch

5.3 Fractionation coefficients according to major diagnosic subcategory types

The fractionation coefficients can also be computed for subsystems of DRG systems.Below, the fractionation coefficients for surgical and medical base DRGs will be con-sidered separately since it is known that the representation quality for medical cases inDRG systems is markedly worse than that for surgical cases.

When we look at Table 8, it is immediately apparent that the DRG systems differMedical DRGs show ahigher degree ofcorrespondence thansurgical DRGs

Table 8

more strongly from each other in the surgical field than they do in the medical field. Avery high degree of correspondence occurs for the medical cases grouped according toAPR-DRG when the IR-DRG system is used as the reference classification (F.medAPR|IR

= 0.06). On the other hand, he high values of the representation of the surgical base IR-DRGs both in AR and in APR are particularly striking (F.chirIR|AR = 0.43; F.chirIR|APR

= 0.37).The representation of the DRG systems in the SQLape code for main procedure orSQLape

main diagnosis (SQp) results in poor fractionation coefficients for both major diagnos-tic subcategory types. In the medical sphere they are slightly better than in the surgicalsphere, unless they are compared with the base IR-DRGs. Whatis interesting is the factthat SQp and SQ1 differ only slightly in relation to the surgical base DRGs. In the med-ical sphere, however, the primary SQLape categories "SQ1" differ much more stronglyfrom the medical base DRGs than the SQLape main treatment categories "SQp".

It is striking that the fractionation coefficient of the representation of the surgicalSQp in the CCS procedures is comparably low: F.chirSQp|CCSis 0.21.

All in all, it appears that the medical base DRGs come somewhat closer to the CCSCCSdiagnosis classification than the surgical base DRGs come tothe CCS procedure clas-sification; however, fragmentation is high in both areas. The representation of APR inCCS is distinctly worse that the representation of IR in CCS,with regard to both diag-noses and procedures (F.chirAPR|CCS= 0.59 in comparison with F.chirIR|CCS = 0.49 andF.medAPR|CCS= 0.43 in comparison with F.medIR|CCS= 0.34).

5.4 Fractionation coefficients according to major diagnosic subcategories

In the next step of the analysis, the fractionation coefficients are computed for eachTables 9 and 10

major diagnosis subcategory.In this instance, comparisons were limited to DRG systems proper. Naturally, a com-Here: DRG systems

only parison with SQLape, LDF and CCS would also be of interest since it would reveal theareas in which similarities might be found despite the overall great divergences notedin the last chapter. In the basic study22, these comparisons were made. For reasons ofspace and clarity, they will not be repeated here.

Large and yellowy-orange symbols indicate great discrepancies between the systemsLarge symbols= great divergence concerned. Columns with a majority of small rectangles show that the cases from the

major diagnosis subcategory type described above them (C: "surgical/procedural" or M:"medical") of the original system were grouped into relatively similar base groups ofthe reference system named below the column.

Areas with high degrees of correspondence exist, for example, between AP and APRAPin the surgical subcategories Eyes [02’C], Circulatory system [05’C], Digestive system[06’C], Hepatobiliary system and pancreas [07’C], Skin [09’C], Glands, metabolism[10’C], Male [12’C], Female [13’C], Birth [14’C] and HIV [24’C]. For all these surgi-cal subcategories, the fractionation coefficient is below 0.05. The Respiratory System[04’C] is a striking exception to this rule.

It is striking in the comparison of the IR system with the other DRG systems, thatIRthere is distinctly more similarity in the medical sphere than in the surgical sphere. It

22 Fischer [Basis-DRG-Vergleiche, 2005].

30.09.2005 (v1.2) 15


must be assumed that this is linked to the fact that a new concept was developed for thesurgical sphere and that hospital cases – unlike in the otherDRG systems – are assignedto a surgical IR-DRG independently of the main diagnosis.

Table 9: Weighted average fractionation coefficient of pair comparisons of DRG systems per system according tomajor diagnosis subcategories (Part 1)

Reference system

Fra

ctio

natio

n co

effic

ient

Sub

cate

gorie

s of

the

orig

inal

sys

tem

AP APR AR IR

01’ Nerves02’ Eye03’ ENT

04’ Respir.05’ Circul.

06’ Digest.07’ Hep+P

08’ MuscTs09’ Skin

10’ Endocr.11’ Kidney

12’ Male13’ Female

14’ Birth15’ Neonat.

16’ Blood17’ Neopl.18’ Infect.19’ Mental

20’ Drug21’ Trauma

22’ Burns23’ Div.Fac

24’ HIV25’ Polytr.

91’ Trp+Trc92’ Day199’ Error

19

950

201

172

5002

437

4547

10

515

24

366

28

31334048

1955

3322

1763

1724

946

880

505053

578

9

64

454

4167

1315211719

5249

4144

662

32859496

6430

9667

606

96

AP : C

AP APR AR IR













2200

90

2617

300

2

4251

1224

6667

162

46

971

198

38

2157

2216

79

2176

20814

88

4849

201921

079

9731

251246

3239

35

2520

545

3919

1112

3943

3133

168

88

9750

AP : M

AP APR AR IR













2957

418

217

2029

5142

298

2233

126139

80

754652

6485

54

359

3353

1016

98

5559

114244

1048

32869396

7744

968781

96

63

325842

2223

58

211

331

38

6118

2765

33

27

APR : C

AP APR AR IR













201

102019

6723

3444

1234

428

8322

5252

2236

2654

80

52

4127533313816

346

313910

11214

816

8887

68

731189

274

2749

332

32389

3828

3937

68

8740

41

APR : M

0.0

0.2

0.4

0.6

0.8

1.0



16 30.09.2005 (v1.2)

www.fischer-zim.ch

Table 10: Weighted average fractionation coefficient of pair comparisons of DRG systems per system according tomajor diagnosis subcategories (Part 2)

Reference system

Fra

ctio

natio

n co

effic

ient

Sub

cate

gorie

s of

the

orig

inal

sys

tem

AP APR AR IR













44910

6917

931

2427

114

420

3364

2424

47

6520

13

347

27

5212

3559

1916

5221

5324

4843

535256

398594

7160

54

811

95

3416

2632

237

342835

291416

934

2335

4

702

39

335

26

AR : C

AP APR AR IR













2730

10914

216

4322

1214

5378

24945

1010

478

51

41

2941

129

20817

45

1822

1547

407

1811

4947

332018

8091

70

2726

51015

85

237714

313

3618

173946

2545

1517

7857

50

AR : M

AP APR AR IR













3346

2777

3652

1545

588

582128

14176

79

3474

5325

3568

2948

7217

6820

611418

75

75

3251

4387

4163

2440

7917

64232937

75

56

IR : C

AP APR AR IR













14263107107

1228

3933

2517

348

1

1

204

1314

2859

223947

2721

3520

1139

212

5065

33

27

13

8712129

344

3121

164

345

362

1310

29404342

8

36

IR : M

0.0

0.2

0.4

0.6

0.8

1.0



30.09.2005 (v1.2) 17


Table 11: Weighted average fractionation coefficient of pair comparisons of DRG systems according to surgicalsubcategories

Original system

Fra

ctio

natio

n co

effic

ient

Ref

eren

ce s

yste

m

AP APR AR IR

AP

APR

AR

IR

29

44

35

33

52

34

6

19

34

31

32

45

C : 01’ Nerves

AP APR AR IR

AP

APR

AR

IR

57

9

9

46

12

74

3 16

33

51

4

C : 02’ Eye

AP APR AR IR

AP

APR

AR

IR

41

10

33

27

35

53

32

9

26

40

43

41

C : 03’ ENT

AP APR AR IR

AP

APR

AR

IR

8

69

53

77

59

25

5

50

32

48

87

67

C : 04’ Respir.

AP APR AR IR

AP

APR

AR

IR

21

17

10

36

19

35

8

2

23

19

41

13

C : 05’ Circul.

AP APR AR IR

AP

APR

AR

IR

7

9

16

52

16

68

4

0

7

5

63

15

C : 06’ Digest.

AP APR AR IR

AP

APR

AR

IR

20

31

9

15

52

29

2

1

34

5

24

21

C : 07’ Hep+P

AP APR AR IR

AP

APR

AR

IR

29

24

8

45

21

48

22

17

28

33

40

17

C : 08’ MuscTs

AP APR AR IR

AP

APR

AR

IR

51

27

55

58

53

72

23

2

35

22

79

19

C : 09’ Skin

AP APR AR IR

AP

APR

AR

IR

42

1

59

8

24

17

2

17

17

52

C : 10’ Endocr.

AP APR AR IR

AP

APR

AR

IR

29

14

11

58

48

68

5

5

9

6

64

49

C : 11’ Kidney

AP APR AR IR

AP

APR

AR

IR

8

4

42

21

43

20

8

0

14

3

23

41

C : 12’ Male

AP APR AR IR

AP

APR

AR

IR

22

20

44

28

53

61

2

0

16

17

29

44

C : 13’ Female

AP APR AR IR

AP

APR

AR

IR

33

33

10

14

52

14

11

2

9

24

37

6

C : 14’ Birth

AP APR AR IR

AP

APR

AR

IR

12

64

48

1

56

18

43

34

62

C : 15’ Neonat.

AP APR AR IR

AP

APR

AR

IR

6

24

32

76

39

75

3

7

23

9

75

32

C : 16’ Blood

AP APR AR IR

AP

APR

AR

IR

13

24

86 85

31

45

35

46

85

C : 17’ Neopl.

AP APR AR IR

AP

APR

AR

IR

9

47

93 94

3

47

4

8

94

C : 18’ Infect.

AP APR AR IR

AP

APR

AR

IR

80

96

8

10

80

96

C : 19’ Mental

AP APR AR IR

AP

APR

AR

IR

79

75

56

C : 20’ Drug

AP APR AR IR

AP

APR

AR

IR

75

65

77 71

61

5

70

50

64

C : 21’ Trauma

AP APR AR IR

AP

APR

AR

IR

46

20

44 60

18

15

2

50

30

C : 22’ Burns

AP APR AR IR

AP

APR

AR

IR

52

13

96 54

27

24

39

53

96

C : 23’ Div.Fac

AP APR AR IR

AP

APR

AR

IR

64

87

65

5

67

C : 24’ HIV

AP APR AR IR

AP

APR

AR

IR

85

34

81 81

33

36

33

78

60

C : 25’ Polytr.

AP APR AR IR

AP

APR

AR

IR

7

1

6

5

9

6

C : 91’ Trp+Trc

AP APR AR IR

AP

APR

AR

IR

54

27

96 95

27

28

26

64

96

C : 99’ Error

0.0

0.2

0.4

0.6

0.8

1.0

Z I M − v1.2 / 1[DRG.AGRP.054.catlevelplot.fraccoefs:c:0:1−059S]


18 30.09.2005 (v1.2)

www.fischer-zim.ch

Table 12: Weighted average fractionation coefficient of pair comparisons of DRG systems according to medicalsubcategories

Original system

Fra

ctio

natio

n co

effic

ient

Ref

eren

ce s

yste

m

AP APR AR IR

AP

APR

AR

IR

20

27

4

1

29

20

7

22

27

19

8

25

M : 01’ Nerves

AP APR AR IR

AP

APR

AR

IR

1

3

1

4

4

4

3

0

26

8

7

1

M : 02’ Eye

AP APR AR IR

AP

APR

AR

IR

10

0

2

2

1

13

11

0

5

3

12

2

M : 03’ ENT

AP APR AR IR

AP

APR

AR

IR

20

10

7

6

12

14

8

9

10

8

12

4

M : 04’ Respir.

AP APR AR IR

AP

APR

AR

IR

19

9

5

3

9

28

9

0

15

21

9

6

M : 05’ Circul.

AP APR AR IR

AP

APR

AR

IR

67

14

3

1

20

59

27

26

8

57

34

32

M : 06’ Digest.

AP APR AR IR

AP

APR

AR

IR

23

2

3

0

8

22

4

1

5

22

4

3

M : 07’ Hep+P

AP APR AR IR

AP

APR

AR

IR

34

16

3

7

17

39

27

7

23

16

31

9

M : 08’ MuscTs

AP APR AR IR

AP

APR

AR

IR

4

4

1

10

4

47

4

3

7

7

21

3

M : 09’ Skin

AP APR AR IR

AP

APR

AR

IR

4

3

3

7

5

27

9

0

7

9

16

5

M : 10’ Endocr.

AP APR AR IR

AP

APR

AR

IR

12

2

8

1

18

21

3

0

14

21

4

25

M : 11’ Kidney

AP APR AR IR

AP

APR

AR

IR

34

2

16

2

22

35

323

7

34

20

M : 12’ Male

AP APR AR IR

AP

APR

AR

IR

4

12

3

2

15

20

3

2

13

6

5

5

M : 13’ Female

AP APR AR IR

AP

APR

AR

IR

28

14

46

8

47

11

236

20

36

45

M : 14’ Birth

AP APR AR IR

AP

APR

AR

IR

8

53

31

39

40

3

3

42

1

8

2

39

M : 15’ Neonat.

AP APR AR IR

AP

APR

AR

IR

3

7

3

3

7

9

8

5

8

14

13

19

M : 16’ Blood

AP APR AR IR

AP

APR

AR

IR

2

8

9

3

18

2

9

1

17

8

10

11

M : 17’ Neopl.

AP APR AR IR

AP

APR

AR

IR

2

2

10

25

11

12

38

12

39

8

29

12

M : 18’ Infect.

AP APR AR IR

AP

APR

AR

IR

52

49

1

17

49

50

28

24

46

48

40

39

M : 19’ Mental

AP APR AR IR

AP

APR

AR

IR

52

45

12

34

47

65

39

66

25

49

43

43

M : 20’ Drug

AP APR AR IR

AP

APR

AR

IR

22

10

14

8

33

33

37

6

45

20

42

31

M : 21’ Trauma

AP APR AR IR

AP

APR

AR

IR

36

10

8 20

6

7

15

19

33

M : 22’ Burns

AP APR AR IR

AP

APR

AR

IR

26

4

16

1

18

27

8

1

17

21

8

16

M : 23’ Div.Fac

AP APR AR IR

AP

APR

AR

IR

54

78

88 80

87

62

78

0

8

M : 24’ HIV

AP APR AR IR

AP

APR

AR

IR

80

51

87 91

40

46

57

79

88

M : 25’ Polytr.

AP APR AR IR

AP

APR

AR

IR

97

97

97

M : 92’ Day1

AP APR AR IR

AP

APR

AR

IR

52

41

68

1

70

13

41

1

50

31

36

50

M : 99’ Error

0.0

0.2

0.4

0.6

0.8

1.0

Z I M − v1.2 / 2[DRG.AGRP.054.catlevelplot.fraccoefs:c:0:1−059S]


30.09.2005 (v1.2) 19


5.5 Major diagnostic subcategories with more problems and with fewer problems

Tables 11 and 12 help find those subcategories which categorise hospital cases in a Tables 11 and 12

relatively similar manner and those with greatly differentgrouping concepts.In the following, those subcategories for which all the representations in other DRG "no problems"

systems resulted in fractionation coefficients of less than0.15 will be regarded as pre-senting "no problems" (at first sight).

In the following, those subcategories for which at least oneof the representations "problematic"in another DRG system among all the DRG systems under scrutiny resulted in an av-erage fractionation coefficient of more than 0.5 will be considered to be (potentially)"problematic".

Among the surgical subcategories, there is only one single subcategory for which all Surgical subcategories↑ Table 11 (p. 18)the comparisons yielded low fractionation coefficients, namely the category with the

transplantations and tracheostomies [91’C].All the other subcategories have fractionation coefficients in excess of 0.4. Only in

three of these subcategories does none of the fractionationcoefficients exceed 0.5.23

Among the medical subcategories, too, there is only one subcategory for which all Medical subcategories↑ Table 12 (p. 19)the comparisons resulted in low fractionation coefficients: ENT [03’M].

The following medical subcategories display problematic differences:

• 06’M: Digestive system

• 15’M: Newborns

• 19’M: Mental diseases

• 20’M: Drugs

• 24’M: HIV

• 25’M: Multiple significant trauma

• 99’M: Not groupable

There is an amazing number of subcategories with differing grouping concepts. In all Commentarythese cases, a closer look is necessary to find the base DRGs that have been subjectedto particularly different treatment.

23 At least one fractionation coefficient is above 0.4 but below0.5 in the subcategories Circulary system[05’C]; Musculoskeletal system [08’C]; Male reproductivesystem [12’C].

20 30.09.2005 (v1.2)

www.fischer-zim.ch

5.6 Example of a treemap for the display of fractionation coefficients

Each of the following treemaps contains all the base DRGs of aDRG system. The↑ Treemaps: p. 9

colours represent the values of the fractionation coefficients per base DRG of the origi-nal system mapped to the reference system.

The graphs are hierarchically divided up according to:Hierarchical structuring

1. major diagnostic subcategory types (vertical main subdivision according to "sur-gical/procedural" and "medical";

2. standardised major diagnostic subcategories (such as "01’M Nerves"; horizontalfields with black frames);

3. base DRGs of the original classification with a white frame, sorted by the valuesof the fractionation coefficient.

The codes for the original classification have been entered at the centre of each white-Codesframed cell. Possibly it is followed by the label of the base DRG (or a short version ofit) and the fractionation coefficient if space is available.The major diagnostic subcate-gories have been entered in italics on the left of each black-framed cell, turned around90° counter-clockwise.

The size of the rectangles reflects the proportion of cases they represents. With theSurface divisionhelp of the vertical subdivision, which separates the casesaccording to major diagnos-tic subcategory types, it can be seen that all in all, the database used contains fewersurgical/procedural cases (on the left) than medical cases(on the right).

The colours correspond to the values of the fractionation coefficients. Low coeffi-Colourscients are shown in a bluish colour, high coefficients in a reddish colour.

The bluer a white-framed cell, the less fragmentated the representation of the dis-played base DRGs of the original system in the base DRGs of thereference system.

The overall number of cases represented from the database isindicated in the centreNumber of cases in thedatabase below the graph.

The first of the two following treemaps displays the fractionation coefficients of all baseIR -> APRTable 13 IR-DRGs split into base APR-DRGs. It is striking immediatlythat there are much more

reddish and red boxes on the left with the surgical base IR-DRGs than on the rightwith the medical base IR-DRGs. A quite great number of medical base IR-DRGs withfractionation coefficients of zero or nearly zero can be seenon the right half. (They arecoloured in a bluish colour.) This means that this graphic tells us, too, that the medicalbase IR-DRGs are less fragmentated into APR-DRGs than the surgical base IR-DRGs:the fractionation coefficient (F.medIR|APR) of the medical base IR-DRGs only amounts↑ Table 8 (p. 14)

to 0.03, whilst the fractionation coefficient of the surgical base IR-DRGs (F.chirIR|APR)is at 0.37.

In the next graphic, also the medical field is now coloured with a more intensiveIR -> ARTable 14 red, but it is still less red than the surgical field. Yet the latter appears to be even more

fragmentated than in the previous graph for IR to APR. A look at the fractionationcoefficients of both fields shows likewise that, though they are higher, they differ less:F.medIR|AR = 0.24, F.chirIR|AR = 0.43.↑ Table 8 (p. 14)

30.09.2005 (v1.2) 21


Table 13: Fractionation coefficients of base IR2005-DRGs divided according to base APR15-DRGs

The size of the boxes corresponds to the number of cases (n_total = 900472).Main division according to subcategory types: C, M (from left to right).

Col

ours

acc

ordi

ng to

val

ues

of fr

actio

natio

n co

effic

ient

s

. .01130x

0.25. .

01110x0.57

01120x0.8101

’ N

erve

s

02120x0.4

02130x0.51

02’

Eye

03115x0.07

.

0311

2x

0313

0x 03120x0.51

0311

1x

03’

EN

T

. 04110x 04130x 0.77 . 04120x 0.9704’

Res

pir.

0511

7x0.

02 .

0510

4x 0

.04

. . .

0514

0x 0

.44

0512

0xIP

Oth

rCrc

lSP

.0.

46 . . . .

0510

6x 0

.75

05115xIPCrdcCthtrz.

0.77

05’

Circ

ul.

0611

4xIP

Ingn

l&F

mH

P.

0.03 06113x

0.04

0611

2x 0

.1

0615

0x0.

21

0612

0xIP

Cm

plxI

ntsP

.0.

52 .

0611

1x 0

.73

.

0614

0xIP

Oth

rDgs

tSP

.0.

9

06’

Dig

est.

07114x 0.01 . . 07113x .07’

Hep

+P08

170x

0.05 ..

0810

4xIP

MjrL

wrE

xtrm

tyJn

t&Lm

bRttc

hmnt

Pr.

0.34

0812

0x IP

Hp&

Fm

rPE

MJ.

0.4

1

0813

0x IP

Foo

t Pro

cedu

res

0.4

1

0818

0x0.

45 . . .

0814

0x0.

7

0816

0xIP

Oth

rMsc

lskl

tlSys

tm&

Cnn

ctvT

ssP

r.0.

77

0815

0x IP

Sof

tTis

suP

roce

dure

s. 0

.81

08’

Mus

cTs

.09150x

0.4309140x

0.7209130x

0.81

09’

Ski

n

.

.

. .11140x

0.54. .

11120x0.6611

’ K

idne

y . . 12114x 0.15 12112x . .12’

Mal

e 1311

0x 13120xIPUtrn&AdnxP.

0.28

13111x0.58

13130xIPVgn,Crv&VP.

0.82

13’

Fem

ale

14612xIPVDWPES&D&C.

0.13 1461

1x 14610xIP Cesarean Delivery

0.36

14’

Birt

h

.

. . . .

. .

.

0141

3x 0

0141

4x0

0141

5x 0

0141

6x 0

0142

3x 0

.. .

0142

2x0.

01

0142

6x0.

01

0142

5xIM

Con

cuss

ion

0.02

0141

7x 0

.17

.

0141

1x0.

47

0142

4x 0

.51

01’

Ner

ves

. .

.

03411x 0 . . . 03413x 0.04 03415x03’

EN

T

04417x0.01

0441

8x 0

.01

.04416x

0.04

0441

4x0.

05

0442

0x 0

.05

0441

5x 0

.07

.

0441

3x 0

.11

.

0441

2x0.

21 04421x0.23

04’

Res

pir.

0541

0x0 .

0541

7x 0

0542

1x0

0541

9x0.

01 .

0541

8x 0

.02

0541

2xIM

Hea

rt F

ailu

re0.

03

0542

4x 0

.03

0541

5x0.

11

0541

6x 0

.13

.. .

0542

0xIM

Ang

nPct

&C

P.

0.49

05’

Circ

ul.

0641

0x 0

0641

1x0 .

0641

5x 0 06417x

IMOthrGst&AP.0.01

.06418x

0.0606

413x

0.33

0641

2x 0

.36

06’

Dig

est.

. 07411x 0 07412x 0 07414x 0 07413x07’

Hep

+P 0841

8x

0841

3x 08417xIMMdclBckPrb.

0.03

08412x0.04

0841

0x

0841

6x

0842

0x

0841

9x 0

.1

.

0842

1x

0841

1x

08’

Mus

cTs

.09414x

0.0909413x

0.109412x

0.23.

09’

Ski

n

10411x 0.02 10413x 10410x 0.4110’

End

ocr.

11412x0

11413x0

. . . .11410x

0.4211’

Kid

ney

. .

.

. . . . . 13416x 0.38 13414x 0.4113’

Fem

ale

14613xIM Vaginal Delivery

0.08

14’

Birt

h

. . .15817x

IMNnt,Brthwt>2499GrmsWthtMjrPrcd.0.39

1581

3x 0

.57

1581

0x 0

.84

15’

Neo

nat.

16411x 16413x 0.03 16410x 16414x16’

Blo

od

17413x0

.17411x

0.0317412x

0.04.

17’

Neo

pl.

18410x 0.05 18412x . 18413x 18411x .18’

Infe

ct.

19411x 0 . . . . . 19416x . 19415x19’

Men

tal

. .

.

. 21412x 0.01 21413x 0.14 . . .21’

Tra

uma

. 22411x 0.01 22412x IMOthrFctrsInflncngHS. 0.0723’

Div

.Fac

. .

.

0.0

0.2

0.4

0.6

0.8

1.0

Z I M − v1.2[DRG.AGRP.059.treemap.fc:IR2005:APR15−059S]


22 30.09.2005 (v1.2)

www.fischer-zim.ch

Table 14: Fractionation coefficients of base IR2005-DRGs divided according to base AR5-DRGs

The size of the boxes corresponds to the number of cases (n_total = 900472).Main division according to subcategory types: C, M (from left to right).

Col

ours

acc

ordi

ng to

val

ues

of fr

actio

natio

n co

effic

ient

s

. .01110x

0.34.

01130x0.35

.01120x

0.8701’

Ner

ves

02130x0.62

02120x0.85

02’

Eye

03115x0.08

0311

2x

0313

0x

.03120x

0.72

0311

1x

03’

EN

T

. 04110x . 04130x 0.86 04120x 0.9604’

Res

pir.

0511

7x0.

02 . .

0510

4x 0

.2

. . . . .05115x

IPCrdcCthtrz.0.68

.

0510

6x 0

.77

0514

0x 0

.77

0512

0xIP

Oth

rCrc

lSP

.0.

84

05’

Circ

ul.

06113x0.03

0611

4xIP

Ingn

l&F

mH

P.

0.05

0611

2x 0

.11

0615

0x0.

19

0612

0xIP

Cm

plxI

ntsP

.0.

68 .

0611

1x 0

.81

.

0614

0xIP

Oth

rDgs

tSP

.0.

92

06’

Dig

est.

07114x 0.02 . 07113x . .07’

Hep

+P

.

0812

0x IP

Hp&

Fm

rPE

MJ.

0.1

4

0817

0x0.

32 . .

0810

4xIP

MjrL

wrE

xtrm

tyJn

t&Lm

bRttc

hmnt

Pr.

0.43

0813

0x IP

Foo

t Pro

cedu

res

0.4

8

..

0814

0x0.

68

0818

0x0.

75

0815

0x IP

Sof

tTis

suP

roce

dure

s. 0

.78

0816

0xIP

Oth

rMsc

lskl

tlSys

tm&

Cnn

ctvT

ssP

r.0.

88

08’

Mus

cTs

.09150x

0.5609130x

0.8809140x

0.89

09’

Ski

n

.

.

.11140x

0.6611120x

0.67. . .

11’

Kid

ney . 12114x 0.07 . 12112x . .12

’ M

ale 13

110x 13111x

0.58

13120xIPUtrn&AdnxP.

0.72

13130xIPVgn,Crv&VP.

0.76

13’

Fem

ale

14610xIP Cesarean Delivery

0.06

14612xIPVDWPES&D&C.

0.14 1461

1x

14’

Birt

h

.

. . . .

. .

0141

6x 0

0141

4x0.

01

0141

3x 0

.02

0142

5xIM

Con

cuss

ion

0.02 .

0142

3x 0

.08

0141

7x 0

.1

.

0142

2x0.

2

0141

5x 0

.21

.

0142

4x 0

.53

0141

1x0.

6 . .

0142

6x0.

79

01’

Ner

ves

. .

.

. 03411x . 03413x 0.2 . 03415x03’

EN

T04

412x

0.02

0441

4x0.

05 04416x0.05

.04417x

0.07

0441

5x 0

.12

0441

3x 0

.15

.

0441

8x 0

.26

.

0442

0x 0

.52

04421x0.78

04’

Res

pir.

0541

7x 0

0542

1x0

0541

0x0.

01

0541

2xIM

Hea

rt F

ailu

re0.

01 . . .

0541

8x 0

.28

0541

9x0.

29 .

0541

5x0.

46

0542

4x 0

.48

0541

6x 0

.49

.

0542

0xIM

Ang

nPct

&C

P.

0.62

05’

Circ

ul.

0641

5x 0

.19

.

0641

0x 0

.39

0641

3x0.

48 .06417x

IMOthrGst&AP.0.69 06

411x

0.78

0641

2x 0

.79

06418x0.82

06’

Dig

est.

. 07411x 07412x 07414x 0.46 07413x07’

Hep

+P

08417xIMMdclBckPrb.

0.08.

0841

9x

0841

8x

0841

6x 08412x0.4

0841

0x

0841

1x

0842

0x

0841

3x

0842

1x

08’

Mus

cTs

.09412x

0.2409413x

0.47.

09414x0.609

’ S

kin

10411x 0.05 10413x 10410x 0.4410’

End

ocr.

11412x0.07

11413x0.12

. . . .11410x

0.5511’

Kid

ney

. .

.

. . . . . 13416x 0.37 13414x 0.4213’

Fem

ale

14613xIM Vaginal Delivery

0.11

14’

Birt

h15

813x

0.0

2

.15817x

IMNnt,Brthwt>2499GrmsWthtMjrPrcd.0.02

. .

1581

0x 0

.69

15’

Neo

nat.

16410x 16411x 16414x 16413x 0.1416’

Blo

od

.17411x

0.0217413x

0.0217412x

0.06.

17’

Neo

pl.

. 18412x 18410x 0.07 . 18413x 18411x18’

Infe

ct.

. . 19416x . 19411x 0.49 . . . 19415x19’

Men

tal

. .

.

. 21412x 0.01 21413x 0.32 . . .21’

Tra

uma

. 22411x 0.27 22412x IMOthrFctrsInflncngHS. 0.7623’

Div

.Fac

. .

.

0.0

0.2

0.4

0.6

0.8

1.0

Z I M − v1.2[DRG.AGRP.059.treemap.fc:IR2005:AR5−059S]


30.09.2005 (v1.2) 23


5.7 Example of a treemap for the comparison of two DRG systems

The next treemap below shows all the base DRGs of the originalsystem again (black- ↑ Treemaps: p. 9

framed), yet this time divided up into the base DRGs of the reference system (white-framed).

These treemaps are hierarchically divided up according to: Hierarchical structuring

1. major diagnostic subcategory types (main subdivision according to "surgi-cal/procedural" and "medical");

2. standardised major diagnostic subcategories (such as "01’M Nerves"; with a finegrey frame at a right angle to the main subdivision);

3. base DRGs of the original classification (with a black frame);

4. base DRGs of the reference classification (with a white frame).

The codes for the original classification have been entered in italics at the bottom of each Codesblack-framed cell, while the codes for the reference classification occupy the centre ofthe white-framed cells. The major diagnostic subcategories have also been entered initalics, but the letters have been turned around 90° counter-clockwise.

The size of the rectangles reflects the proportion of cases they represents. The main Surface divisionsubdivision distinguishes between the surgical/procedural cases and the medical cases.

The colours were determined on the basis of the (sequential)code numbers of the Coloursreference classification. White rectangles indicate a combination of base DRGs andreference base DRGs with fewer than three cases.

The fewer stripes and the fewer colours the field of a base DRG contains, the better Correspondence ofclassificationsthe base DRG in question corresponds to the group structure of the reference classifica-

tion.The overall number of cases represented from the database isindicated in the centre Number of cases in the

databasebelow the graph (or, in the portrait format print-out, to theleft of the graph).

The treemaps below can be interpreted as follows: Notes concerninginterpretation

• Large rectanglesrefer to frequent codings or coding combinations.

• The smaller thenumberof white-framed base DRGs of the reference systemwithin a base DRG of the original system, the more similar thegrouping conceptused for these base DRGs in both systems.

• The more uniform thecolour gradient, the more base DRGs of the original sys-tem are represented in base DRGs of the reference system whose codes are as-signed to similar thematic areas.

• Conspicuous colourspoint to the fact that the same hospital cases are encoded indifferent thematic areas.

• An in-depth analysis should not only compare the colours but also thelabelsof the base DRGs of the original system and the assigned base DRGs of thereference system.

• If the reference classification has a goodclinical homogeneity, then the graphmay serve as a basis for an estimate of the clinical homogeneity of the originalclassification.

24 30.09.2005 (v1.2)

www.fischer-zim.ch

Table 15: Base IR2005-DRGs divided according to base AR5-DRGs

The area corresponds to the proportions of cases related to the IR

2005 subcategory.n_total =

900472

01.B02

... ....

01.B02: Craniotomy

.........................

01110x: IP C

raniotomy

....B

02.....

. ..01.B04

.........01112x

..01.B

05...

01113x

.......

01.B06...........................................

01120x

.......

08.I10: OthrBckAndNP.

.......

01130x: IPS

pinPrcdrs.

01’ Nerves

.........

02.C1002.C1102.C12..............

02120x

......

02.C03: Retinal Procedures...

02.C15: Glaucoma And Complex Cataract Procedures

02.C16: Lens Procedures

......

02130x: IP Intraocular &

Lens Procedures

02’ Eye

..

...

. ....

D02

.........R02

.. ...

03.D06

......03112x

.03.D05

03.D14

.... .

.....

. ...

03.D11: TnsllctmyAnd/rAdndctm.

......

03115x: IPT

onsil&A

denodPrcdrs.

............

03.D06: Sns,MstdAndCmplxMddEP.

03.D09: MscllnsEr,Ns,Mth&ThrP.

03.D10: Nasal Procedures

........................

03120x: IPO

thrEr,N

s,Mth&

ThrtP

.

......03.D

14........

.03’ ENT

.A

06....

04101x

.

PRE.A06

....

04102x

.......04.E01...........

04110x

....................................................................................................................

04120x: IPN

n−Cm

plRS

P.

........

04.E01: Major Chest Procedures.....................................

04130x: IPM

drtlyCm

plxRsprtrS

P.

04’ Respir.

..

..

..

..

..

...

..

....

..

.. ...

05.F04: C

rdcVlvP

rcWC

PB

PW

/OIC

I..

F07... .

05.F05: C

rnryBypssW

InvsvCrdcI.

05105x

.......................05.F

06

05.F07.

05.F09......

05.F19....................................................................05106x: IP

OtherC

rdthrccPrcdrs.

..05.F

06: CrnryB

ypssW/O

InvsvCrI.

.05107x

....

......

. .......

..

...

. .......05.F

08: MjrR

cnstrctVsclrP

rcdr.............

. ..05.F

12: CardiacP

acmkrIm

plnttn..

.... .....................

05.F10: PrctnsCrnryIntrvnWAMI.

05.F15: PrctnsCrnryIW/OAMIWSI.

05.F16: PrctnsCrnIW/OAMIW/OSI.....

05.F42: CircultryDsrdrsW/OAMI.

.................................

05115x: IP C

ardiac Catheterization

..

..

... .

05.F20: V

ein Ligation And S

tripping....

05117x: IP V

ein Ligation & S

tripping

.................

05.F08

...05.F14

..

05.F19........05.F

65....................................................................

05120x: IPO

thrCrcltryS

ystmP

rc.

.........

05.F17: C

rdcPcm

krRpl.

..05130x

...05.F10

05.F15

F16..05.F

21F

42.

05140x: IPP

rctnsCrdvsclrP

rcdr.

05’ Circul.

...

.G

02.

.06.G

05...G

11....................

. .........06.G

04...H

08.........

N04

N05.

N07...

N11........... .....

06.G08: A

bdmnlA

ndOthrH

rnPrcdr.

.......06112x: IP

HrnP

rcdrsExcptIng&

F.

..06.G

07: Appendicectom

y.....

06113x: IP A

ppendiceal Procedures

.....06.G

09: IngnlAndF

mrlH

rnPrA

g>0.

........

06114x: IPIngnl&

Fm

rlHrnP

rcdrs.

........

06.G01

06.G02

06.G03................

10.K04.............................

06120x: IP C

omplex Intestinal P

rocedures

.....06.G

03.....

G12

.........10.K

04.........

..

.06130x

..........

06.G0406.G07.06.G09.06.G12................................

13.N0413.N05.

13.N07

13.N08

.......

14.O66...........

06140x: IPO

thrDgstvS

ystmP

rcdr.

......06.G

11: Anal A

nd Stom

al Procedures

................

06150x: IP A

nal Procedures

06’ Digest.

.. .......

07.H01

..............

07110x

....H

02...

. .....07.H07

...

07112x

......07.H08.........

07113x

..

07.H08: Laparoscopic Cholecystectomy

....

07114x: IP Laparoscopic C

holecystectomy

07’ Hep+P

..

...

.....

...

..

..

.........

. ...

.B

03.

...

08.I09: Spinal F

usion..........

. ......08.I03: H

ip Replacem

ent Or R

evision08.I04

...........

08104x: IPM

ajorLowerE

xtremityJoint&

LimbR

eattachmentP

rocedures.

...

...

..

..

..

....

. ........08.I08: O

ther Hip A

nd Fem

ur Procedures

..................08120x: IP

Hip &

Fem

ur Procedures E

xcept Major Joint

.......05.F13.....

08.I12

08.I13...

08.I20: Other F

oot Procedures

...................08130x: IP

Foot P

rocedures

................

08.I12

08.I13

...08.I18

08.I1908.I2108.I23: LclE

xcsn&R

mvlO

IFD

EH

AF

.....................

08140x: IP Local E

xcision & R

emoval O

f Internal Fixation D

evice

....................

08.I13.

08.I16.

08.I18.

08.I24.08.I27: S

oft Tissue P

rocedures

08.I29

.......

09.J08

09.J11...............

X06...08150x: IP

Soft T

issue Procedures

............

03.D04.....08.I10

.

08.I13

08.I16

.08.I18

..08.I24.

08.I28

08.I29

........................

08160x: IPO

therMusculoskeletelS

ystem&

ConnectiveT

issueProcedures.

........08.I13: H

umerus, T

ibia, Fibula A

nd Ankle P

rocedures

08.I18

.

08.I29

...........

08170x: IP K

nee & Low

er Leg Procedures E

xcept Foot

...........08.I13

08.I16.

08.I19: OthrE

lbwO

rFP

....

08.I30................

08180x: IP U

pper Extrem

ity Procedures

08’ MuscTs

961...

22.Y02

. .........................

08.I02......

09.J0809.J12....................

09130x

................................................................

09.J09: PerianlAndPlndlPrcdrs.

.

09.J11: OthrSkn,SbctnsTssAnBP..........................................................

09140x: IPO

thrSkn,S

bctnsTs&

BP

.

....

09.J06: MjrPrcdrsFrBrstCndtns.

09.J07: MnrPrcdrsFrBrstCndtns.

................

09150x: IP B

reast Procedures

09’ Skin

.

10.K02. ... ......

10.K06: Thyroid Procedures......

10120x

..P

RE

.A09

. ..L03

............ ....F

21.....

L09....

11112x

......

11.L03: Kdny,UAMBPFN.

11.L04: Kd,UAMBPFN−N........

11.L42: ESWLthtrpFUS.

.................

11120x: IPU

pprUrnryT

rctPrcdrs.

.....

11.L06

...............11130x

...................................................

11.L07: TransurethrlPrcdrsExcptPrsttctmy.

...........................................

11140x: IP U

rethral & T

ransurethral Procedures

11’ Kidney

...12.M

01

12110x

.....12.M03

.... ..........12.M

04.....

12112x

..........

12.M04

.

12.M06..........

12113x

....

12.M02: Transurethral Prostatectomy

....

12114x: IP T

ransurethral Prostatectom

y

..12.M

05.

.12’ Male

..

..

...

.. .961

...14.O

05..

13110x

........13.N

10....14.O

05.....

13111x

..

...

..

. ........

13.N04: HystrctFNn−M.

13.N05: Op&CFTPFNn−M..

13.N07: OthU&APFNn−M.

.............

13120x: IPU

trn&A

dnxP.

..............

13.N04: HystrctmyFrNn−Mlgnncy.

13.N06: FmlRprdctvSystmRcnstP...

13.N09: Cnstn,Vgn,CrvxAndVlvP.

...............

13130x: IPV

agn,Crvx&

VlvP

rcdrs.

13’ Female

.......

14.O01: Caesarean Delivery

......

14610x: IP C

esarean Delivery

.14.O

02.

O60.14611x

...

14.O60: Vaginal Delivery

..

14612x: IPV

gnlDlvryW

PE

S&

/OD

&C

.

14’ Birth

. ... . .... . .. .. . ... .... ..

PRE.A08........

. ................

. ........................................16120x

. ................ .

C

..

..

. ......

01.B63

01.B66

01.B67

..

01411x: IMN

rvsSyM

&D

D.

..

01.B68: M

ltplSclrA

CA

.. .

01.B70: S

troke01413x: IM

Nn−T

rmtcIH

.

..01.B

70: Stroke

01414x: IMC

rbrvscAW

I.

.

B69

01.B70: S

troke01415x: IM

N−S

C&

P−O

WI.

.01.B

69: TIA

AndP

rcrbO.

01416x: IM T

ransient Ischemia

........01.B

71: CrnlA

ndPrpN

D.

...01417x: IM

Crnl&

PrpN

D.

..

..

. ..B

7101.B

72.

01419x.

..

. ..01.B

7001.B

74B

81.

. ....

01.B75

01.B76: S

eizure

01422x: IM S

eizure

..01.B

77: Headache

.. ...01.B

78: IntrcrnlInjr.

01.B79

....

X60

01424x: IM H

ead Traum

a

....01.B

80: Other H

ead Injury..

01425x: IM C

oncussion

........

01.B6601.B67

01.B70..01.B

8104.E

63....

01426x: IMO

thrNrvsS

D.

01’ Nerves

.

C60. 02.C61. ............ ..03.D60

03410x

.

03.D61: Dysequilibrium

.

03411x

03.D62

03412x

...

03.D63: Otitis Media And URI

....

03413x: IME

pglttts,OM

d,UR

TI&

L.

...

03.D67

..

03414x

......

03.D66

....

03415x

03’ ENT

..

04.E60: C

ystic Fibrosis

. ..

04.E64

E75

. ..04.E

61: Plm

nryEm

blsm.

04412x: IMP

lmnryE

mbl.

..04.E

66: MajorC

hstTrm

....

. ...04.E

71: RsprtryN

plsm.

04414x: IMR

sprtryMlg.

....04.E

62: RspInfctns/I.

....04415x: IM

RsprtryI&

I.

...

04.E62: RsprtryInfctns/Inflmm.

...

04416x: IMS

mplP

nm&

WC

.

...04.E

65: ChrncO

bstrAD

.

04417x: IMC

hrncObsP

D.

.04.E

69: BrnchtsA

ndAs.

E70.

04418x: IMA

sthm&

Brnc.

...

. ....04.E

6804.E

73..

. .......

04.E64

04.E67

04.E69

....

04.E75

..........

04421x: IMR

SS

gn,S&

OD

.

04’ Respir.

..05.F

60: CirculatoryD

srdrsWA

MI.

05410x: IMA

cutMyocardlInfrctn.

..

. ...05.F

62: Heart F

ailure And S

hock

05412x: IM H

eart Failure

.05.F

63: Venous T

hrombosis

..

...

. ...

05.F6305.F64

05.F65: P

rphrlVsclrD

.....

05415x: IMP

rphrl&O

thrVsclrD

sr.

..05.F

6605.F

7505416x: IM

Atherosclerosis

.05.F

67: Hypertension

05417x: IM H

ypertension

..F68

05.F69: V

alvular Disorders

... ..

05.F70

05.F71: N

n−M

jrArrA

CD

..

05419x: IMC

rdcArr&

CD

.

.

05.F66

05.F72

05.F74

05420x: IMA

nginPectors&

ChstP

n.

.05.F

73: Syncope A

nd Collapse

05421x: IM S

yncope & C

ollapse

.05.F

75: OthrC

rcltrySystm

Dgnss.

. ....

.. ....

F60F66F74

05.F75: O

thrCrcltrS

D.

..05424x: IM

OthrC

rcltrySystm

Dgn.

05’ Circul.

...

06.G42..

06.G46

06.G60

06410x: IMD

gstvMlgnn.

..06.G

42.

06.G4506.G46

06.G61.

06.G63

06.G67

.

06411x: IMP

ptcUlcr&

G.

..

G42.06.G45

G46G61.06.G

67

G69..06412x: IM

EsphglD

srd.

...

06.G44.06.G

61

06.G64

06413x: IMD

vrt,D&

IBD

.

..

..

. .....06.G

65: GI O

bstruction

06415x: IMG

strntstnO.

.......

. .....

06.G66: AbdmnlPnOrMsntrcAdnts.

06.G67: Osphgts,Gstrnt&MscDSD.

06.G68: Gastroenteritis.....

06417x: IMO

thrGstrntrts&

Abdm

P.

........

06.G44: Other Colonoscopy.

06.G46: CmplxGstrscp..

06.G61: GI Haemorrhage..

06.G67: Osphg,G&MDSD.

..

06.G70: OthrDgstvSyD.

........

06418x: IMO

thrDgstS

D.

06’ Digest.

.07.H60

07410x

....07.H61

07411x

..07.H62.

07412x

.....

07.H60.

07.H63

......

07413x

..

07.H42: ERCPOtherTherptcPrcdr.

07.H64: DisordersOfThBlryTrct.

07414x: IMO

therBlryT

rctDsrdrs.

07’ Hep+P

.

I60I61.08.I78

.. .

08.I63

08.I76

08.I77..

08411x

...

08.I74

08.I75....

08412x: IMF

rctOD

EF

&P

.

....08.I65

.08.I69

08413x

...

....

.. ......

08.I66.

08.I69..08416x: IM

CnnctvT

ssD.

........

08.I68: Non−surgical Spinal Disorders

...

08417x: IM M

edical Back P

roblems

..08.I69

08.I70.08418x: IM

OthrB

n&JnD

.

..08.I73

I76

08419x

........08.I71

..

08.I75

...08420x

..........08.I72

08.I73..

08.I76

......

21B.X60.

08421x

08’ MuscTs

....

09.J60

09.J68.

09410x

..09.J62

09411x

....

09.J64: Cellulitis

...

09412x: IM C

ellulitis

.....

09.J65: TrmTThSkn,SbctnsTssAB.

...

21B.X60: Injuries

09413x: IMT

rmT

ThS

kn,SbctnsT

&B

.

..........09.J67

09.J68

...

09414x

09’ Skin

.....

10.K60: Diabetes...

10410x

...

10.K62: MscllnsMtblD.

..

. .....

.. ...

10.K64: EndcrnDsrdrs.

.

.10’ Endocr.

...11.L60

11.L62

.

11410x

.11.L67

. ....

11.L63: KdnyAndUrnryTrctInfct.

...

11412x: IMK

dny&U

rnryTrctInfct.

....

11.L64: UrinryStnsAndObstrctn.

11413x: IM U

rinary Stones

..11.L67

..11414x

....11.L65

...11415x

..............11.L67

...

11416x

11’ Kidney

...

12.M60: Malignancy, Male Reproductive System. ...........12411x

. .13.N

60.

13410x

.13.N

6113411x

...13.N62

13412x

...14.O63

13413x

..

14.O64: False Labour

14.O66: Antntl&OthOA.

13414x: IMT

hrtndAbrt.

.14.O

64. ....

14.O66: Antenatal & Other Obstetric Admission

13416x: IM A

ntepartum D

isorders

.14.O

61.13’ Female

.

14.O60: Vaginal Delivery

..

14613x: IM V

aginal Delivery

14’ Birth

.

961.

P01.....15.P

60....

P65.15.P

6715810x

..

...

.. ..

15.P66: N

,AW

2000−2499G

W/O

SO

.P.

15813x

.15.P

67: Nnt,A

W>

2499GW

/OS

O.R

.P.

15814x.

...

. ...

15.P67: Neonate, AdmWt > 2499 G W/O Significant O.R. Proc

15817x: IM N

eonate, Birthw

t >2499 Gram

s Without M

ajor Procedure

15’ Neonat.

16.Q60.

. .

16.Q62.

. .. . ..

16.Q61: Red Blood Cell Disorders..

16413x

.

16.Q60...

16414x

.

.17.R

6017410x

...17.R

61.

17411x

...

17.R64: Radiotherapy

17412x: IM R

adiotherapy

..

17.R63: Chemotherapy

.

17413x: IM C

hemotherapy

....

17.R61

17.R62

17414x

17’ Neopl.

....

18B.T60: Septicaemia

.

18410x: IM S

epticemia

..

18B.T61

.

18411x

...

18B.T62

18412x: IM F

ever

...

18B.T63: Viral Illness

.

18413x: IMN

n−BctrlIn.

.....

18B.T64

18414x

.S

65.18’ Infect.

.

U61

... ..

19.U63: MajorAffectivDisordrs.

19.U64: OthrAffctASD.

19411x: IM M

ajor Depression

...

U65U67

. ...U

63. ...

19.U67

19414x

.....

19.U65: AnxityDsrdrs....

19415x

..

01.B63

01.B64: Delirium....

19416x

..

.. .U

66. ..

19.U65

..19419x

19’ Mental

....... .......

20411x

.

20.V64

.. ......

X60

21410x

X61

. ..

21B.X62: Psnng/TxcEffctsOfDrgs&OthrSbstnc.

21412x: IM P

oisoning & T

oxic Effects O

f Drugs

....

21B.X63: SeqlOfTrtmnt.

21413x: IMC

mplctnsO

T.

..

...

... ....

Y62

. .....X64

21417x

21’ Trauma

.

23.Z60

22410x

.......

23.Z61: Signs And Symptoms

22411x: IM S

igns & S

ymptom

s

.................

23.Z64: Other Factors Influencing Health Status

22412x: IM O

ther Factors Influencing H

ealth Status

23’ Div.Fac

......................

990029

ERR.960: Ungroupable

. . ...... .. .. . ....

M

Z I M

− v1.1 / 1

[DR

G.A

GR

P.054.treem

ap.IR..A

R−

059RD

atabase: S

wissD

RG

/ Sw

iss Federal S

tatistical Office

30.09.2005 (v1.2) 25


Basically, the colour pattern looks rather calm. This meansthat the classifications IR -> ARTable 15have a similar overall structure: the hospital cases are classified into similar "coding

zones" by both DRG systems.A detailed observation reveals that there is a considerablenumber of base IR-DRGs

that are represented in several base AR-DRGs: this is the case wherever a black-framedfield is divided up into several white-framed subsections.

The most striking are base IR-DRG fields that bear several colours: in this case, thebase AR-DRGs into which this base IR-DRG is divided also belong to subcategoriesthat are "further distant". The most conspicuous example ofthis kind is base IR-DRG06140x (IP Other Digestive System Procedures) almost in thecentre of the graph. Thesize of the field shows that a relatively high number of hospital cases have been assignedto this collective base IR-DRG. In the AR-DRG system, the same cases can be foundboth in the subcategory "Digestive system" [06’C] and under"Female reproductivesystem" [13’C].

Another example that is plain to see is provided by the strongfragmentation of thebase IR-DRGs of procedures on the musculoskeletal system [subcategory 08’C]. Theprevalent yellow colour shows that the base AR-DRGs according to which these caseswere grouped are frequently to be found in the same subcategory.

5.8 Examples of individual DRG-related evaluations

In the following, the fragmentation of the base APR-DRG 313 (Knee & lower legprocedures except foot) will be shown through its representation in the AR-DRG sys-tem, in the IR-DRG system and in the AP-DRG system. The fractionation coefficient isrelatively high for all three representations, namely approximatelyf = 0.6.

When the hospital cases from base APR-DRG 313 are represented in the AR-DRG APR 313 -> ARTable 16system, it becomes evident that these cases are mainly assigned to three base AR-DRGs,

namely: base AR-DRG I13 (Humerus, Tibia, Fibula and Ankle Procedures), base AR-DRG I18 (Other Knee Procedures) and base AR-DRG I29 (Knee Reconstruction OrRevision). As in APR, foot procedures are also represented in a separate DRG.24 Nev-

24 Foot procedures : base APR-DRG 314 (Foot procedures); base AR-DRG I20 (Other Foot Procedures).

Table 16: Example: APR 313 according to AR (f=0.61, n=21378): Knee & lower leg procedures except foot

APR Cases%APR %AR Type MDC AR AR-DRG label313 11204 52.4 74.7 C 08 I13 Humerus, Tibia, Fibula and Ankle Procedures313 6804 31.8 99.5 C 08 I18 Other Knee Procedures313 2549 11.9 98.9 C 08 I29 Knee Reconstruction Or Revision313 254 1.2 16.8 C 08 I12 Infect/Inflam Bone & Joint313 90 0.4 7.4 C 08 I21 Local Excision & Removal of Internal Fixation Devices of Hip and Femur313 88 0.4 1.5 M ERR 961 Unacceptable Principal Diagnosis313 74 0.3 1.3 M 08 I75 Injury to Shoulder, Arm, Elbow, Knee, Leg or Ankle313 47 0.2 1.5 C 08 I28 Other Connective Tissue Procedures313 43 0.2 0.8 C 08 I20 Other Foot Procedures313 35 0.2 1.0 M 08 I69 Bone Diseases & Spec Arthropathies313 25 0.1 0.3 C 08 I08 Other Hip and Femur Procedures313 23 0.1 4.2 C 21B X04 Other Procedures for Injuries to LowerLimb313 21 0.1 42.0 C 08 I11 Limb Lengthening Procedures313 18 0.1 0.4 C 08 I04 Knee Replacement and Reattachment313 17 0.1 0.5 C 08 I30 Hand Procedures313 16 0.1 1.0 M 08 I76 Other Musculoskeletal Disorders313 11 0.1 0.5 M 01 B60 Established Paraplegia/Quadriplegia

26 30.09.2005 (v1.2)

www.fischer-zim.ch

ertheless, only half of the APR-313 cases come into the nominally comparable baseAR-DRG I13 (cf. column marked "%APR"). On the strength of thelabel of AR-DRGI13 it becomes clear that this also includes procedures on the humerus (i. e. not onlyon the lower but also on the upper extremity). This explains why only three quartersof this base AR-DRG contains cases from base APR-DRG 313 (cf.column marked"%AR"). Evidently, the APR-DRGs in this context are less differentiated at the level ofbase DRGs than AR-DRGs; part of this might be compensated forby the four severitycategories that are systematically available in the APR-DRG system. However, it turnsout that in the AR-DRG system, I13, too, has three severity categories whereas I18 andI20 have no further subdivisions.25

When the hospital cases from base APR-DRG 313 were represented in the IR-DRGAPR 313 -> IRTable 17 system, they were mainly positioned in five base IR-DRGs, namely: base IR-DRG

08170x (IP Knee & Lower Leg Procedures Except Foot), base IR-DRG 08160x (IPOther Musculoskeletel System & Connective Tissue Procedures), base IR-DRG 08140x(IP Local Excision & Removal Of Internal Fixation Device), base IR-DRG 08150x (IPSoft Tissue Procedures) and, interestingly, 3.9 % of the cases also in base IR-DRG08130x (IP Foot Procedures), even though the label of APR-DRG 313 should reallyexclude any procedures on the foot. What is particularly confusing, however, is the factthat the labels of base APR-DRG 313 and base IR-DRG 08170x areidentical26, and yetnot even half of the APR-313 cases are assigned to base IR-DRG08170x (cf. columnmarked "%APR"). At any rate, almost all the cases to be found in base IR-DRG 08170x,namely 97.6 %, are assigned to base APR-DRG 313 (cf. column marked "%IR").

When the hospital cases from base APR-DRG 313 were represented in the AP-DRGAPR 313 -> APTable 18

25 There are separate DRGs in both systems for replantations and prostheses: base APR-DRG 301 (Majorjoint & limb reattach proc of lower extremity for trauma) undbase APR-DRG 302 (Major joint & limbreattach proc of lower extrem exc for trauma); base AR-DRG I04 (Knee Replacement and Reattachment).

26 Base IR-DRG 08170x is solely preceded by "IP". In the IR-DRG system, "IP" identifies all stationaryprocedures (I = inpatient, P = procedure).

Table 17: Example: APR 313 according to IR (f=0.65, n=21378): Knee & lower leg procedures except foot

APR Cases%APR %IR Type MDC IR IR-DRG label313 10484 49.0 97.6 C 08 08170x IP Knee & Lower Leg Procedures Except Foot313 6364 29.8 36.5 C 08 08160x IP Other Musculoskeletel System & Connective Tissue Procedures313 2482 11.6 19.2 C 08 08140x IP Local Excision & Removal Of Internal Fixation Device313 1100 5.1 15.2 C 08 08150x IP Soft Tissue Procedures313 831 3.9 10.6 C 08 08130x IP Foot Procedures313 46 0.2 1.9 C 01 01120x IP Cranial & Peripheral Nerve Procedures313 18 0.1 0.4 C 04 04130x IP Moderately Complex Respiratory System Procedures313 13 0.1 0.1 C 05 05120x IP Other Circulatory System Procedures313 12 0.1 0.3 C 05 05106x IP Other Cardiothoracic Procedures

Table 18: Example: APR 313 according to AP (f=0.59, n=21378): Knee & lower leg procedures except foot

APR Cases%APR %AP Type MDC AP AP-DRG label313 11486 53.7 76.0 C 08 A-218 Lower Extremity & Humerus Procedures Except Hip, Foot, Femur313 7306 34.2 99.4 C 08 A-221 Knee Procedures313 1510 7.1 13.3 C 08 A-231 Local Excision & Removal Of Int FixDevices Except Hip & Femur313 814 3.8 14.4 C 08 A-226 Soft Tissue Procedures313 110 0.5 8.3 C 08 A-230 Local Excision & Removal Of Int Fix Devices Of Hip & Femur313 63 0.3 2.4 C 23 A-461 O.R. Procedures W Diagnoses Of Other Contact W Health Services313 62 0.3 6.2 C 25 A-732 Other O.R. Procedures For Multiple Significant Trauma313 15 0.1 0.1 M 27 A-901 Transfer Within One Day

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system, they were mainly positioned in five base AP-DRGs, namely base AP-DRG A-218 (Lower Extremity & Humerus Procedures Except Hip, Foot,Femur), base AP-DRGA-221 (Knee Procedures), base AP-DRG A-231 (Local Excision& Removal Of Int FixDevices Except Hip & Femur) and base AP-DRG A-226 (Soft Tissue Procedures). Thislast base AP-DRG has a counterpart in the APR-DRG system, namely base APR-DRG317 (Soft tissue procedures). This raises the question as towhether it is a positioning inAPR-DRG 313 or an assignment to base AP-DRG A-226 that fits thesituation better.

A complementary example to be shown is the representation ofthe hospital cases from AR I13 -> APTable 19base AR-DRG I13 (Humerus, Tibia, Fibula and Ankle Procedures) in the AP-DRG

system. This is a relatively homogeneous representation: 96.9 % of the hospital casesin AR-DRG I13 will be found again in base AP-DRG A-218 (Lower Extremity &Humerus Procedures Except Hip, Foot, Femur). The representation also works wellin the opposite direction: 96.2 % of the hospital cases in base AP-DRG A-218 are as-signed to base AR-DRG I13. This relatively good correspondence is also indicated by Table 20

the fractionation coefficients off = 0.06 andf = 0.07, respectively.In this case, the different natures of AR and AP become evident only at the next lower

level. Base AR-DRG I13 is divided up into three severity categories: I13A applies tocases with severe or catastrophic comorbidities or complications; all other cases areassigned to I13B if patients are over 59 years of age, whilst I13C is for patients under60. In contrast, there is AP-DRG 218 for "Lower Extremity & Humerus ProceduresExcept Hip, Foot, Femur, Age > 17, with CC"; AP-DRG 219, the same, but withoutCC; and AP-DRG 220 for patients below 18 years.

Table 19: Example: AR I13 according to AP (f=0.06, n=14999): Humerus, Tibia, Fibula and Ankle Procedures

AR Cases %AR %AP Type MDC AP AP-DRG labelI13 14538 96.9 96.2 C 08 A-218 Lower Extremity & Humerus Procedures Except Hip, Foot, FemurI13 220 1.5 22.0 C 25 A-732 Other O.R. Procedures For MultipleSignificant TraumaI13 101 0.7 7.0 C 08 A-217 Wound Debridements & Skin GraftsI13 75 0.5 2.8 C 23 A-461 O.R. Procedures W Diagnoses Of Other Contact W Health ServicesI13 27 0.2 1.1 C 21 A-442 Other O.R. Procedures For InjuriesI13 15 0.1 0.1 M 27 A-901 Transfer Within One Day

Table 20: Example: AP A-218 according to AR (f=0.07, n=15115): Lower Extremity & Humerus ProceduresExcept Hip, Foot, Femur

AP Cases %AP %AR Type MDC AR AR-DRG labelA-218 14538 96.2 96.9 C 08 I13 Humerus, Tibia, Fibula and Ankle ProceduresA-218 155 1.0 10.3 C 08 I12 Infect/Inflam Bone & JointA-218 82 0.5 2.6 C 08 I28 Other Connective Tissue ProceduresA-218 59 0.4 1.1 M 08 I75 Injury to Shoulder, Arm, Elbow, Knee,Leg or AnkleA-218 51 0.3 0.8 M ERR 961 Unacceptable Principal DiagnosisA-218 33 0.2 0.4 C 08 I08 Other Hip and Femur ProceduresA-218 31 0.2 1.7 M 08 I74 Injury to Forearm, Wrist, Hand or FootA-218 24 0.2 48.0 C 08 I11 Limb Lengthening ProceduresA-218 21 0.1 0.6 M 08 I69 Bone Diseases & Spec ArthropathiesA-218 20 0.1 1.2 M 08 I76 Other Musculoskeletal DisordersA-218 15 0.1 0.3 C 08 I10 Other Back and Neck ProceduresA-218 11 0.1 0.5 M 01 B60 Established Paraplegia/Quadriplegia

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The representation of the hospital cases of base APR-DRG 313within the referenceAPR 313 -> SQpTable 21 classification of SQLape main treatment categories (SQp) reveals that main treatments

comprise mainly procedures on the leg ("CRU"), especially on the knee ("GEN") andalso – inspite of the exclusion done by the APR-DRG label – on the foot ("PED2" and"PED3").

The representation of the hospital cases of base APR-DRG 313within the referenceAPR 313 -> SQ1Table 22 classification of primary SQLape categories (SQ1) is even more interesting. They mir-

ror the main treatments or diagnoses determined by the SQLape system based on theevaluation of all diagnoses and procedure codes. The fragmentation is slightly smaller.The first three SQ1 categories cover approximately 80 % of thehospital cases. Thefirst seven SQ1 categories concern the legs ("CRU"), the knees ("GEN") and the foots("PED"). It would be worthwhile to take a look at the case datain order to judge ifSQLape or APR did the groupings of the "PED" cases and of the hospital cases leftover in a more adequate manner.

Table 21: Example: APR 313 according to SQp (f=0.77, n=21378): Knee & lower leg procedures except foot

APR Cases %APR %SQp Type MDC SQp SQp label313 8372 39.2 96.4 C L CRU3 Major operation on leg313 4279 20.0 89.6 C L GEN2 Excision of knee structures313 2590 12.1 33.9 C L GEN4 Open operation on knee313 2350 11.0 41.4 C L ART1 Arthroscopy or traction313 1133 5.3 65.3 C L CRU2 Minor operation on leg313 697 3.3 14.6 C L PED2 Minor operation on foot313 512 2.4 86.9 C L GEN3 Other arthroscopic operation on knee313 425 2.0 21.4 C L PED3 Major operation on foot313 225 1.1 2.5 C L OSS2 Removal of internal fixation device313 109 0.5 3.7 C L OSS4 Other operation on unspecified bone313 101 0.5 6.6 M L L-tZ Other severe injury313 93 0.4 13.9 C L ART3 Major operation on joint313 64 0.3 3.4 M L L-iO Musculoskeletal system inflammation313 53 0.2 1.8 C L MUS3 Other operation on muscle313 47 0.2 7.9 M L L-dG Degenerative disease of knee313 43 0.2 10.1 C L OSS3 Excision of unspecified bone313 40 0.2 1.0 M L L-tC Fracture of pelvis313 37 0.2 2.2 M L L-tJ Leg injury313 37 0.2 1.2 M L L-tL Other musculoskeletal injury313 30 0.1 0.1 M Z Z-zZ Other disorders313 20 0.1 1.3 C L ART2 Minor operation on joint313 19 0.1 1.2 C L MUS2 Excision or suture of muscle313 17 0.1 0.1 C T CUT1 Minor operation on tegument313 15 0.1 0.3 C L BRA4 Forearm minor operation

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Table 22: Example: APR 313 according to SQ1 (f=0.74, n=21378): Knee & lower leg procedures except foot

APR Cases %APR %SQ1 Type MDC SQ1 SQ1 label313 9003 42.1 94.7 C L CRU3 Major operation on leg313 4647 21.7 88.1 C L GEN2 Excision of knee structures313 3803 17.8 42.6 C L GEN4 Open operation on knee313 713 3.3 91.2 C L GEN3 Other arthroscopic operation on knee313 621 2.9 59.3 C L CRU2 Minor operation on leg313 608 2.8 23.0 C L PED3 Major operation on foot313 591 2.8 14.5 C L PED2 Minor operation on foot313 177 0.8 3.6 M Z Z-zM Without valid information313 161 0.8 4.3 C L MUS3 Other operation on muscle313 148 0.7 1.8 C L OSS2 Removal of internal fixation device313 146 0.7 15.4 C L ART3 Major operation on joint313 113 0.5 6.8 C L ART2 Minor operation on joint313 62 0.3 11.4 C L OSS3 Excision of unspecified bone313 48 0.2 1.3 M L L-iO Musculoskeletal system inflammation313 39 0.2 0.5 C L COX4 Other major operation on hip313 38 0.2 1.3 C L OSS4 Other operation on unspecified bone313 33 0.2 0.4 M N N-fC Epilepsy313 32 0.1 12.5 C L COX3 Minor operation on hip313 24 0.1 1.3 C N NER3 Operation on nerves313 23 0.1 0.2 M U U-iU Urinary infection313 22 0.1 2.1 M L L-tZ Other severe injury313 21 0.1 0.6 C L SCA3 Other major operation of shoulder313 15 0.1 0.2 C C COR2 Heart operation without circulatory assistance313 15 0.1 0.1 M S S-mS Lymphoma, other leukemia or hematopoetic malignat neoplasm without

complication313 13 0.1 0.1 C D ABD3 Unilateral repair other hernia313 12 0.1 0.4 M P P+xS Chronic substance abuse313 11 0.1 0.5 M C C-zC Other cardiac disease313 11 0.1 0.3 M L L-tC Fracture of pelvis313 10 0.0 0.2 C C VAS2 Operation on varicose limb veins

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6 Discussion and prospects

It has been revealed that the fractionation coefficient is basically an interesting mea-sure to describe the relative difference in the nature of patient classification systems.

In the following, a number of discussion points are listed, which at the same timeserve as suggestions for further work.

Standardisation of the major diagnostic categories:↑ p. 7

• Following the example of the IR-DRG system, major diagnostic categories withfew groups and hospital cases could be subsumed. This would concern HIV, forinstance, which would be assigned to infections, or polytraumata, which wouldbe divided up among various major diagnostic categories.

• The DRGs of the former major diagnostic category of transplantations and tra-cheostomies was dispersed within the IR-DRG system. In analogy, the baseDRGs in other DRG systems could be removed from this major diagnostic cate-gory and assigned to the main categories of the organ systemsconcerned.

• Besides major diagnostic categories, "DRG-Klassen" could be introduced as anadditional hierarchical level, which would serve to unite similar base DRGs in atighter structure.27

Base DRGs:↑ p. 6

• The definition of base DRGs could be made more precise. In this manner, addi-tional individual DRGs could be subsumed even though the manufacturer definedthem as separate DRGs.

fractionation coefficient:↑ p. 8

• In the weighting process, a distinction could be introduced between groups of thereference system that are positioned within the same DRG subcategory (or withinthe same DRG-Klasse; cf. above) and others.

• In the aggregation of the fractionation coefficients at thelevel of subcategorytypes and at system level, the error groups could be excludedor given specialtreatment. (In particular, this is necessary where the nature of the system results inmany false classifications, as for instance with LDF, where transcoding obviouslystill has many deficiencies.)

Treemaps:↑ p. ??

• At present, the colouring of the base DRGs of the reference system is baseddirectly on their code numbers. This will yield acceptable results particularly ifthe system under scrutiny is structured according to a hierarchy that is similar tothat of the reference system. It would be better, however, tocolour base DRGs onthe basis of a common logical order that would still have to bedefined.

Pair analysis of patient classification systems:↑ p. 24

• So far, a detailed view of individual base DRGs of a originalsystem and theirbreakdown according to basic case groups of the reference classification has onlybeen provided by means of examples. This should be systematised.

27 Base DRGs can be subsumed in a "DRG-Klassen", i. e. a kind of "product group" or "product line",according to thematic resemblance. Cf. among others Krüger/Lenz [2004]; http:// www.adimehp.com /G-GHM.htm; Buronfosse et al. [OAP manuel 3.0, 2003]; Buronfosse et al. [OAP court séjour, 2002];Ruiz [GA+GF, 1999], as well as the "product lines" in the PMC system: PRI [PMC-Rel.5, 1993].

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• Some information could be added about the proportions of the cost weights.

• A way of representing the breakdown of a base DRG into several selected refer-ence classifications should be developed.

• Comparisons between DRGs and SQLape categories still require further devel-opment.

Thematic comparisons: ↑ p. 26

• DRG systems could be compared with each other in thematic terms, as someexamples adduced in this text have shown.

Further fields of application:

• The fractionation coefficient can be used to analyse the correspondence betweena DRG system and an alternative patient classification system (such as the »mipp›system28 used by individual hospitals in the Swiss Canton of Aargau).

• The fractionation coefficient and treemaps in particular could be used to detectcoding differences within individual DRGs.

• The fractionation coefficient and treemaps could be used tovisualise differencesof versions of a single DRG system from year to year.

28 Cf. Rieben et al. [Pfadkostenrechnung, 2003]: 29 ff.

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7 Appendix

7.1 Table of abbreviations

Table 23: Abbreviations and LinksAbbreviation Designation Links and referencesAP-DRG All Patient Diagnosis Related Groups http:// www.fischer-zim.ch / text-pcssa /

t-ga-E4-System-AP-0003.htmAPR-DRG All Patient Refined Diagnosis Related Groups http:// www.fischer-zim.ch / text-pcssa /

t-ga-E5-System-APR-0003.htmAR-DRG Australian Refined Diagnosis Related Groups http://www.fischer-zim.ch / artikel /

ARDRG-0105-SGMI.htmCCS Clinical Classification Software http:// www.ahrq.gov/ data / hcup / ccsicd10.htmCC Comorbidity or ComplicationCHUV Centre hospitalier universitaire vaudois http:// www.hospvd.ch / public / chuv /DRG Diagnosis Related Groups http:// www.fischer-zim.ch / streiflicht /

DRG-Familie-9512.htmD.S. Disease Staging http:// www.fischer-zim.ch / streiflicht /

Disease-Staging-9603.htmEfP Effeuillage Progressif http:// www.fischer-zim.ch / text-pcssa /

t-ga-E8-System-GHM-0003.htm#zimEfPG-DRG German Diagnosis Related Groups http:// www.g-drg.de /G-GHM Groupements de Groupes Homogènes de

Maladeshttp:// www.adimehp.com / G-GHM.htm

GHM Groupes homogènes de malades http:// www.atih.sante.fr /LDF Leistungsbezogene Diagnosen-Fallgruppen http:// www.bmgf.gv.at / cms / site / themen.htm ?

channel=CH0005IR-DRG International Refined Diagnosis Related

Groupshttp:// www.3m.com / us / healthcare / his / pdf / reports /ir_drg_whitepaper_09_02.pdf

MCC Major Comorbidity or ComplicationMDC Major Diagnostic Category»mipp› Modell integrierter Patientenpfade http:// www.mipp.ch /OAP Outil d’Analyse PMSI http:// membres.lycos.fr / pradeau / PMSI /

telechargements / OAP_acceuil.htmPMC Patient Management Categories http:// www.fischer-zim.ch / streiflicht / PMC-9511.htmPMSI Programme de médicalisation des systèmes

d’informationhttp:// www.le-pmsi.org / index.html

RDRG Refined Diagnosis Related Groups http:// www.fischer-zim.ch / text-pcssa /t-ga-E3-System-RDRG-0003.htm

SFSO Swiss Federal Statistical Office http:// www.bfs.admin.ch /SQ1 Primary SQLape category (For this study only)SQLape Striving for Quality Level and Analysis of

Patient Expenditureshttp:// www.sqlape.com /

SQp SQLape main treatment category (For this study only)SwissDRG Swiss Diagnosis Related Groups http:// www.swissdrg.org /ZIM Zentrum für Informatik und wirtschaftliche

Medizinhttp:// www.fischer-zim.ch /

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7.2 References

3M (1998) AP-DRG-CH3M Health Information Systems.AP-DRGs All Patient Diagnosis Related Groups Version 12.0.Adapted for Switzerland 1.0, Definitions Manual. Wallingford Borken 1998: 1408 pp.

APDRG-CH (2003) CW 4.1APDRG Schweiz.Kostengewichte Version 4.1. Prilly (ISE) 2003. Internet: http:// www.isesuisse.ch /de / apdrg / o_rapport_cw_v41_d.pdf.

BFS-CH (1997) Medizinische StatistikBundesamt für Statistik.Statistik der stationären Betriebe des Gesundheitswesens. MedizinischeStatistik. Detailkonzept 20.5.97, Bern 1997.

BMGF-A (2004) LKF05-ModellBundesministerium für Gesundheit und Frauen [Hrsg.].Leistungsorientierte Krankenanstaltenfi-nanzierung – LKF. Modell 2005. Wien (BMGF) 2004: 42 pp. Internet: http:// bmgf.cms.apa.at / cms/ site / attachments / 4 / 6 / 6 / CH0036 / CMS1039004330660 / modell_2005.pdf.

Buronfosse et al. (2002) OAP court séjourBuronfosse A, Duportail P, Delhommeau A, Martin S, Lepage E.Utilisation de l’outil d’analysePMSI (OAP) court séjour. In: Info en santé 2002/1: 3–5. Internet: http:// fhf.ecritel.net / fhf / docs /lettreinfo / infosante1.pdf.

Buronfosse et al. (2003) OAP manuel 3.0Buronfosse A, Discazeaux, Echard, Lellouch, Vollaire.Classification OAP: version 3.0 (Analyse desdonnées PMSI 2002). Manuel d’utilisation. (Assistance Publique Hôpitaux de Paris) 2003: 6 pp. In-ternet: http:// gimep.free.fr / oap_v30.zip.

Fetter et al. (1991) DRGsFetter RB, Brand A, Dianne G [Hrsg.].DRGs, Their Design and Development. Ann Arbor (HealthAdministration Press) 1991: 341 pp.

Fischer (1997) PCSFischer W.Patientenklassifikationssysteme zur Bildung von Behandlungsfallgruppen im stationärenBereich. Prinzipien und Beispiele. Bern und Wolfertswil (BSV+ZIM)1997: 514 pp. Auszüge: http://www.fischer-zim.ch / studien / PCS-Buch-9701-Info.htm.

Fischer (2002) DRG+PflegeFischer W.Diagnosis Related Groups (DRGs) und Pflege. Grundlagen, Codierungssysteme, Inte-grationsmöglichkeiten. Bern (Huber) 2002: 472 pp. Auszüge: http:// www.fischer-zim.ch / studien /DRG-Pflege-0112-Info.htm.

Fischer (2005) Basis-DRG-VergleicheFischer W.Vergleich von Basis-DRGs verschiedener DRG-Systeme. Auswertungen zur klinischenHomogenität der Systeme: APR-DRG 15, AR-DRG 5, IR-DRG 2005,SQLape 2005. Wolfertswil(Z I M) 2005: 114 pp. Internet: http:// www.fischer-zim.ch / studien / Basis-DRG-Vergleich-0507-Info.htm.

Fischer (2005) KH-VergleicheFischer W.Neue Methoden für Krankenhaus-Betriebsvergleiche. Ein Werkstattbuch zur Visual-isierung DRG-basierter Daten. Wolfertswil (Z I M) 2005: 160pp. Auszüge: http:// www.fischer-zim.ch / studien / KBV-0506-Info.htm.

Freeman JL et al. (1991)Freeman JL, Fetter RB, Park H, Schneider KC, et al.Refinement. In: Fetter et al. [DRGs, 1991] 1991:57–78.

Krüger/Lenz (2004)Krüger R, Lenz MJ.G-APDRG: Ein synthetisches Beschreibungsmodell der Krankenhausleistungen,entwickelt auf der Grundlage der G-GHM. In: 5. Deutsche Casemix-Konferenz, Konferenzdokumen-tation 2004: 257–264.

Mullin et al. (2002) IR-DRGMullin R, Vertrees J, Freedman R, Castion R, Tinker A.Case-Mix Analysis Across Patient Populationsand Boundaries. A Refined Classification System Designed Specifically for International Use. 2002: 6pp. Internet: http:// www.3m.com / us / healthcare / his / pdf/ reports / ir_drg_whitepaper_09_02.pdf.

PRI (1993) PMC-Rel.5PRI (The Pittsburgh Research Institute).Patient Management Categories. A ComprehensiveOverview. Pittsburgh (The Pittsburgh Research Institute)1993: approx. 65 pp.

Rieben et al. (2003) PfadkostenrechnungRieben E, Müller HP, Holler T, Ruflin G.Pfadkostenrechnung als Kostenträgerrechnung. Kalkulationund Anwendung von Patientenpfaden. Landsberg (ecomed) 2003: 279 pp.

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Roeder et al. (2004) G-DRG 2005 (II)Roeder N, Fiori W, Bunzemeier H, Fürstenberg T, Hensen P, Loskamp N, Franz D, Glocker S, WenkeA, Reinecke H, Irps S, Rochell B, Borchelt M.G-DRG-System 2005: Was hat sich geändert? (II).Spezifische Änderungen in medizinischen Leistungsbereichen. In: Das Krankenhaus 2004/12: 1022–1039. Internet: http:// www.drg-research.de / de / downloads / literatur / kh1204_drg2005_teil_2.zip.

Ruiz (1999) GA+GFRuiz J.PMSI et Groupes de produits. Exemple: Groupes fonctionnels, Groupes d’activités. 1999: 4pp. Download unter: http:// www.adimehp.com / GAGF.htm.

Schwab/Meister (2004) CMISchwab P, Meister A.Der Case Mix Index – ein Mass für den durchschnittlichen Schweregrad derKrankenhausfälle. Neuchâtel (Bundesamt für Statistik) 2004: 33 pp.

Shneiderman (1992) TreemapsShneiderman B.Tree visualization with tree-maps. 2-d space-filling approach. In: ACM Transactionson Graphics (TOG) 1992(11)1: 92–99.

Zahnd (2003) CCSZahnd D.Medizinischen Statistik der Krankenhäuser: Clinical Classification System (CSS). Ein Hilf-smittel für die Auswertung der Medizinischen Statistik. In: CodeInfo (2/03) 2003/14: 5–11. Internet:http:// www.bfs.admin.ch / bfs / portal / de / index / themen /gesundheit / uebersicht / blank / pub-likationen.Document.48977.html.

Zahnd (2004) CCSZahnd D.Die Analyse von Diagnose- und Behandlungsdaten mit dem CCS System. Eine «zweiteSicht» auf DRGs. In: 5. Deutsche Casemix-Konferenz, Konferenzdokumentation 2004: 38–41.

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