The inter-relationship between length-of-stay, readmission and death: impact on hospital

outcomes

P.J. Marang-van de Mheen, H.F. Lingsma, A. Bottle, S. Middleton,

J. Kievit, E.W. Steyerberg

Disclosures

• No funding for this research

• No pay for talks, advice or conference attendence

Background

• Hospital mortality, readmission & Length-of-Stay (LOS)

commonly used outcomes to measure quality of care

• Problem: interrelation between outcomes affecting

interpretatation

• Deaths included in LOS models

• Deaths not included in readmission models

• Mortality models not adjusted for

readmission and LOS

Purpose of the study

1. Disentangle the relationship between mortality, readmission

and LOS, on patient and hospital level

2. Propose new measure to jointly report these 3 outcome

measures to facilitate insight and evaluation of quality of

care -> less ambiguous interpretation of hospital specific

outcomes

Patients and outcomes

Patients

• Global Comparators Project, 26 hospitals in 6 countries

• Patients discharged between 2007-2012

• All patients, stroke, heart failure and colorectal patients

Outcomes:

Mortality, readmission and prolonged LOS (>75 percentile)

Results: descriptives

All patients Stroke Heart Failure Colorectal

Number 4,327,105 83,163 85,024 35,537

Mortality rate 3.1% 13.6% 6.7% 5.0%

Readmission (survivors)

7.8% 7.3% 16.9% 10.6%

Long LOS 20.8% 20.7% 20.7% 22.6%

Range of standardized outcomes at hospital level:• Mortality: 55-146 • Readmission: 57-124• Long LOS: 51-170

Results: relationships at patient level

Mortality Readmission

All patients

Long LOS 1.45 (1.43-1.47) 1.37 (1.35-1.38)

Stroke patients

Long LOS 0.46 (0.43-0.49) 1.16 (1.08-1.25)

Heart Failure patients

Long LOS 1.38 (1.29-1.47) 1.17 (1.11-1.23)

Colorectal patients

Long LOS 1.31 (1.16-1.47) 1.34 (1.23-1.45)

Odds Ratios adjusted for case-mix & center

Results: correlations at hospital level

• Mortality – readmission:

r= -0.06 p=0.76

• Mortality – long LOS

survivors: r=0.79 p<0.01

• Readmission – long LOS

survivors: r= -0.20 p=0.33

• Long LOS (survivors) – long

LOS (deaths): r=0.77 p<0.01Similar results for upper decile LOS

Composite measure based on 3 outcomes, 5 levels

1. Survivors, no readmission, normal LOS (best)

2. Survivors, no readmission, long LOS

3. Survivors, readmission, normal LOS

4. Survivors, readmission, long LOS

5. Deaths (worst)

• Literature evidence suggests that patients consider

readmission as worse quality of care than long LOS

• Presented at expert meeting (N≈ 100) for agreement

• Analysed using ordinal regression – single standardized rate

to compare hospitals

Variation in composite measure

All patients: 44-172

Stroke: 33-168

Colorectal: 30-246

HF: 30-246

Upper decile LOS: similar, smaller variation

Results: correlation composite with individual outcomes

• Mortality: r=0.78 p<0.01

• Readmission: r= -0.07

p=0.72

• Long LOS: r=0.98 p<0.01

Similar results when constructed with upper decile LOS

Composite measure versus individual outcomes

• Composite measure has

similar or better efficiency to

estimate hospital effect

• Rankability: reliability of

ranking hospitals

• Rankability of composite

measure is similar or better

than individual measures

Conclusions and discussion

• Three outcomes: better total picture of quality of care

• Summary measure:

• Ordering based on content

• Good statistical properties to discriminate between hospitals

• Large influence of LOS? Similar results for upper decile LOS

• No weighting applied, but is possible

• Direction where to improve

Did we improve?

• More patients alive, without

readmission & normal LOS

=> on average better care

• Smaller variance between

hospitals => more uniform

better care

Similar for upper decile LOS