Understanding Surveillance Data and NHSN Basics final · 11/10/2014 · Understanding Surveillance...

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Understanding Surveillance

Data and NHSN Basics

Module 2

Joan N. Hebden MS, RN, CIC

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Learning Objectives

• State three differences between clinical and surveillance definitions of infection

• Explain the data on the device-associated NHSN output table

• Define the value of presenting both device-associated infection rates and device utilization ratios when providing feedback to bedside providers

• Define the value of calculating both incidence and prevalence rates for trending multi-drug resistant organisms

• Define the importance of an epidemic curve during an outbreak investigation

• Understand how to use the NHSN analytic tools for identifying events and the significance of differences in data

Current State of HAI Surveillance

Courtesy of Daniel Pollock, MD: NHSN -Changing Purposes March 12, 2014

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Competency in Infection Prevention

IPC Domain: Novice IP

• Epidemiology and

Surveillance

– Conducts surveillance:

standardized , basic case finding

methods and application of HAI

definitions

– Is learning to use NHSN

– Performs manual chart review,

data abstraction and data

collection

Defining HAI Surveillance

• SHEA Consensus Panel on essential activities of IPC

programs in hospitals -1998)

– HAI surveillance most important data management activity

– Surveillance process to include: standardized definitions of

numerators and denominators, identification and description of data

sources and data collection personnel and selection of appropriate

methods of measurement (Category I recommendation)

– Additional Category I recommendation emphasized the need for

appropriate data analysis to monitor and improve HAI outcomes

Scheckler WE, Brimhall D, Buck AS, et al. Requirements for infrastructure and essential activities of infection

control and epidemiology in hospitals: a consensus panel report. Am J Infect Control 26(1):47-60

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Source: Stone, P.W., Dick A., Pogorzelska, M., Horan, T.C., Furuya, E.Y., Larson, E. Staffing and Structure of Infection Prevention and Control Programs. American Journal of Infection Control, Volume 37, Issue 5, June 2009, Pages 351-357. Note: Data total does not equal 100 due to rounding.

Data-Related

Activities

How IPs Spend Their Time

Prevention

Activities

44.5

15

12.9

13

8.86.1

Collecting, Analyzing & Interpreting Data on the Occurrence of Infections

Policy Development & Meetings

Daily Isolation Issues

Teaching Infection Prevention & Control Policies and Procedures

Other (e.g., Product Evaluation, Employee Health & Emergency Preparedness)

Activities Related to Outbreaks

Understanding Surveillance Data

Surveillance Definitions

• Identify trends within a

population for the purpose

of prevention and research

• Comply to limited, pre-

determined data components

• Objective: clinical judgment

introduces potential bias

Clinical Diagnoses

• Identify disease in, and

treatment needs for,

individual patients

• All diagnostic information is

used for decision making

• Subjective: clinical

judgment is valued

Adapted from Bridson, KA NHSN Patient Safety Component Manual

2014

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• Essential elements of surveillance• Assess the patient population and identify those at greatest risk

for the outcome and process measures of interest: outcome =

HAI; process = practices aimed at HAI prevention

• Select the outcome and process measures

• Determine the surveillance time period

• Choose the surveillance methodology

• Monitor the selected measure using standardized definitions

• Collect denominator data for rate calculation

• Analyze the data

• Report the data in a timely manner

HAI Surveillance Overview

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• Surveillance methodology

• CDC recommends active, prospective, targeted

surveillance that yields risk-adjusted incidence rates

• ACTIVE: trained personnel (IP) vigorously look for HAIs

using a variety of data sources

• PROSPECTIVE: during the patients’ hospitalization and for

SSIs post-discharge for the defined surveillance period

• TARGETED: surveillance objectives defined with focus on

specific events, organisms, procedures

• RISK-ADJUSTED: variations in the distribution of major

risk factors associated with the occurrence of an event are

controlled – allows for inter-and intra-hospital comparisons


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• INCIDENCE: count only new events during the defined time

period; PREVALENCE: count all events -new and previously

existing

• Numerator data collection

� What to collect

�Demographic: name, gender, admit date, medical record

number, medicare beneficiary number: REGISTRATION

(ADT)

� Infection data: onset date, site of infection, location of HAI

onset

�Risk factors: devices, procedures, comorbidities e.g. diabetes,

obesity

�Laboratory and microbiology data

�Radiology


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� How to collect

�Screen ADT data for high-risk patient admissions and

patients admitted with infection – recent discharge?

�Reviews lab and microbiology data – positive cultures,

unusual organisms e.g Legionella pneumophila

�Ward rounds

�Reviews disparate data of patients suspected to have an HAI

– physician and nursing notes, radiology, surgery reports, lab

• Denominator data collection

• Device days

• Patient admissions/days

• Surgical procedures


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� Complete

� Accurate

� Timely

High Quality Surveillance Data

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High Quality Surveillance Data

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HAI Type Step 1 Step 2

CLABSIReview every positive blood

cultureReview for presence of central line

SSIIdentify and review all post-

op patients and

readmissions (30d or 90d)

• Review readmission reports; ICD-9 DC

coding

• Review reoperation reports

CAUTIReview every positive urine

cultureReview for presence of a urinary catheter

LabID

Review all final test results

for specific events e.g

MRSA bloods, C. diff toxin

assays

• If positive in ED, review for admission

to inpatient unit on same day

• Review length of time between positives

on the same patient

Review of a minimum clinical dataset for all patients up to the

point where the HAI is ruled out

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CDC/NHSN Surveillance Definitions

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http://www.cdc.gov/nhsn/PDFs/pscManual/17pscNosInfDef_current.pdf

Device-Associated (DA) Infection Rates

• Calculated as an incidence density rate (IDR)

• To calculate the IDR, you need:

– Numerator: # of new cases for a time period

– Denominator: person-time during the same period

– A multiplier for interpretation

• NHSN DA rates:

– Central Line-Associated BSI

– Catheter-associated UTI

– Ventilator-associated pneumonia

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Calculating a DA rate for CAUTI

• What measure of person-time is used in the

calculation of CAUTI rates in NHSN?

1. Patient days

2. Patient admissions

3. Catheter insertions

4. Catheter days

Calculating a DA rate for CAUTI

• ANSWER: 4. Catheter days

• Calculation is based on person-time for those at

risk of infection for that HAI type

• Example:

# of CAUTIs in the MICU for a specific month x 1000

# of catheter days for that same month

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Interpreting DA Rates

• How would you

interpret the MICU’s

CAUTI rate of 1.827?

1. 1.8 per 1000 catheter

days

2. 1.8%

3. 1.8 per 1000 pt. days

4. 1.8 times higher than

the national

Interpreting DA Rates

• How would you

interpret the MICU’s

CAUTI rate of 1.827?

1. 1.8 per 1000 catheter

days

2. 1.8%

3. 1.8 per 1000 pt. days

4. 1.8 times higher than

the national

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Interpreting DA Rates: The p-value

Determining with 95% probability that your outcome did

not occur by chance: p = <0.05; very small probability that

it occurred by chance – 5%


The p-value is included in the DA rates output in NHSN:

What is compared? Your facility’s location DA rate to the

pooled mean for the same location

Is the CAUTI rate for the MICU significantly different

from the NHSN pooled mean based on the p-value?

1. Yes

2. No

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Is the CAUTI rate for the MICU significantly different

from the NHSN pooled mean based on the p-value?

1. Yes

2. No The p-value is > 0.05

How well are we doing?

• External Benchmarking

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NHSN Data Summary

• Aggregated report of HAI surveillance data

• Purposes:– Allow for trend recognition

– Provide risk-adjusted metrics for inter-facility comparisons and local QI

– Assist facilities in developing surveillance and analysis methods that permit timely recognition of patient safety issues and prompt intervention

NHSN Data Summary: Pooled Mean

(265/78,825) x 1000 = 3.4

Pooled mean is not an “average” –

weighted mean that pools the data within

the strata

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Interpreting DA Rates: Percentiles

• Percentile provides a value at which a percentage of the

distribution falls at or below; the NHSN output data table includes

the exact percentile of where your rate falls on the published

Distribution

• The 25th percentile, 25% of the facilities had lower rates and 75%

had higher rates

Interpreting DA Rates: Percentiles

• Why use percentiles?

– Provide the full range of rates in the location type

– “Where do we fall in that range?”

– Assists with establishing an external benchmark

other than the NHSN pooled mean

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NHSN Source of Aggregate Data Used for Comparisons

( pooled means/percentiles)

Use of DU Ratios

• Device Utilization (DU)

Ratios

• A measure of the use

of invasive devices

which constitutes an

extrinsic risk factor for

HAI

• May serve as a

marker of severity of

illness of the patient

population

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DU Ratios

0.32 = 32% of the patient-days were also central-line days

29% of the reporting MICUs had a DU at or lower than the MICU’s DU ratio

Turning Data into Knowledge!

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0

2

4

6

8

10

12

14

CCU MICU CSICU SICU NCICU PICU NICU NTCC MTCC T6CC

Above NHSN Target �At NHSN Target �Less than NHSN Target �

NHSN pooled mean comparison

Above NHSN Target �At NHSN Target �Less than NHSN Target �

NHSN pooled mean comparison

Rate

per

1,0

00 C

L D

ays

ICU Location

ICU Central Line-Associated BSI Rates -

By Quarter

Quarterly Data – 3 Quarters of 2009

Horizontal Bar = NHSN Target by ICU

Type

0

0

Surveillance for MDROs

• Rationale:

– Detect newly emerging antimicrobial resistance

patterns

– Identify vulnerable patient populations

– Assess the need for and effectiveness of interventions

• Why?

– Increasing incidence

– Severity of infections

– Changing in reporting requirements

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• Estimating infection burden:

– Overall burden of MDROs in the facility

– Incidence of HA-MDRO bacteremia; + BC are easy to track, highly likely to represent infection; shown to decrease in response to interventions

– Specific organism device- or procedure-associated incidence e.g CRE infections among catheterized patients, MRSA sternal wound infections in CABG pts.

Cohen et al. SHEA/HICPAC Position Paper. Recommendations for MDRO Metrics

Oct. 2008; 29(10).


• Estimating exposure burden

– “colonization pressure” – the amount of exposure of

patients to MDRO colonized or infected pts. who

could potentially transmit the organism to them

– Overall prevalence of MDRO clinical cultures: newly

identified and historical

– MDRO prevalence based on clinical cultures alone

underestimates the full reservoir; if facility is

performing active surveillance screening, should be

included

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– The proportion of persons in a population with a particular disease at a:

• specific point in time (point prevalence)

• Over a specified time period (period prevalence)

– Point prevalence surveys assist with identification

of areas with high endemicity where enhanced

surveillance may be useful

– Admission prevalence: the magnitude of MDRO

importation into the facility

An Outbreak of A. baumannii

• Clonal outbreak of MDR-AB in a SICU; no environmental source identified

• Baseline mean attack rate 3/100 pts./month; from Feb 1-Mar 22, attack rate rose to 16/100 pts/month ( 18 infections): dropped to 4/100 pts./month after educational intervention

• Case-control study ( 36 non-infected): only independent risk factor was the prevalence of pts. with MDR-AB infections

• “Colonization pressure” increased the likelihood of cross -transmission

D’Agata EMC, et al. ICHE 2000; 21:588-

91

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Assessment of the Prevalence of MDR-AB in Maryland

• Purpose: to assess the state-wide prevalence of MDR-AB

among mechanically-ventilated patients

• Define the burden of MDR-AB in both acute-care and LTAC

patients

• 2-week period prevalence

• The high prevalence of AB and the molecular findings with

evidence of a highly endemic process and patient-to-patient

transmission defined a need to increase interventions aimed at

reducing AB acquisition and spread

Thom KA, et. al. ICHE September 2012; 33(9)


Is there a statistically significant difference in the proportion of

acute vs. LTC facilities with A. baumannii?

1. Yes

2. No

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Is there a statistically significant difference in the

proportion of acute vs. LTC facilities with A. baumannii?

1. Yes. P-value is <0.05

2. No

NHSN Surveillance and

Analysis Tools

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Ventilator-Associated Event (VAE) Surveillance Tool

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• http://www.cdc.gov/nhsn/labid-

calculator/index.html#

MDRO & CDI LabID Event Calculator

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MDRO & CDI LabID Event Calculator

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NHSN Statistics Calculator

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NHSN Statistics Calculator – Compare

Two Proportions

• Publicly reported HAI surveillance data should be defined by standardized case-finding and consistently applied objective criteria

• Statistical data provided through NHSN output tables and the published data summary allows for benchmarking of rates which are risk-adjusted and can be used for inter-facility comparisons

• Incidence rates are valuable for estimating infection burden

• Prevalence rates are valuable for evaluating MDRO exposure burden and for assessment of targeted interventions

• An epidemic curve is an essential tool for detecting and tracking infection occurrences which exceed endemic levels

Summary

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Understanding Surveillance Data and NHSN Basics final · 11/10/2014 · Understanding Surveillance...

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