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Quantifying Sources of Bias in National Healthcare Safety Network Laboratory-Identified Clostridium difficile Infection Rates

Published online by Cambridge University Press:  10 May 2016

Valerie B. Haley*
Affiliation:
Bureau of Healthcare-Associated Infections, New York State Department of Health, Albany, New York
A. Gregory DiRienzo
Affiliation:
Department of Epidemiology and Biostatistics, State University of New York at Albany, New York
Emily C. Lutterloh
Affiliation:
Bureau of Healthcare-Associated Infections, New York State Department of Health, Albany, New York Department of Epidemiology and Biostatistics, State University of New York at Albany, New York
Rachel L. Stricof
Affiliation:
Council of State and Territorial Epidemiologists, Atlanta, Georgia
*
Bureau of Healthcare-Associated Infections, New York State Department of Health, Corning Tower, Room 523, Albany, NY 12237 (vbh03@health.ny.gov)

Abstract

Objective.

To assess the effect of multiple sources of bias on state- and hospital-specific National Healthcare Safety Network (NHSN) laboratory-identified Clostridium difficile infection (CDI) rates.

Design.

Sensitivity analysis.

Setting.

A total of 124 New York hospitals in 2010.

Methods.

New York NHSN CDI events from audited hospitals were matched to New York hospital discharge billing records to obtain additional information on patient age, length of stay, and previous hospital discharges. “Corrected” hospital-onset (HO) CDI rates were calculated after (1) correcting inaccurate case reporting found during audits, (2) incorporating knowledge of laboratory results from outside hospitals, (3) excluding days when patients were not at risk from the denominator of the rates, and (4) adjusting for patient age. Data sets were simulated with each of these sources of bias reintroduced individually and combined. The simulated rates were compared with the corrected rates. Performance (ie, better, worse, or average compared with the state average) was categorized, and misclassification compared with the corrected data set was measured.

Results.

Counting days patients were not at risk in the denominator reduced the state HO rate by 45% and resulted in 8% misclassification. Age adjustment and reporting errors also shifted rates (7% and 6% misclassification, respectively).

Conclusions.

Changing the NHSN protocol to require reporting of age-stratified patient-days and adjusting for patient-days at risk would improve comparability of rates across hospitals. Further research is needed to validate the risk-adjustment model before these data should be used as hospital performance measures.

Type
Original Article
Copyright
Copyright © The Society for Healthcare Epidemiology of America 2014

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References

1. Johnson, S, Gerding, DN. Clostridium difficile. In: Mayhall, CG, ed. Hospital Epidemiology and Infection Control. 3rd ed. Philadelphia: Lippincott Williams & Wilkins, 2005:623634.Google Scholar
2. Lucado, J, Gould, C, Elixhauser, A. Clostridium difficile infections (CDI) in hospital stays, 2009. Statistical brief 124. Healthcare Cost and Utilization Project (HCUP) Statistical Briefs. Rockville, MD: US Agency for Health Care Policy and Research, 2012.Google Scholar
3. National Healthcare Safety Network (NHSN) manual: patient safety component protocol. Centers for Disease Control and Prevention website, http://www.cdc.gov/nhsn/. Accessed April 23, 2013.Google Scholar
4. Centers for Medicare and Medicaid Services. Acute Inpatient Prospective Payment System. http://www.cms.gov/Medicare /Medicare-Fee-for-Service-Payment/AcutelnpatientPPS/index.html. Accessed August 18, 2013.Google Scholar
5. Statewide Planning and Research Cooperative System (SPARCS) overview. New York State Department of Health website. http://www.health.ny.gov/statistics/sparcs/. Accessed February 18, 2013.Google Scholar
6. Whalen, D, Pepitene, A, Graver, L, Busch, JD. Linking client records from substance abuse, mental health and Medicaid state agencies. Technical monograph. Rockville, MD: US Department of Health and Human Services Substance Abuse and Mental Health Services Administration, 2001.Google Scholar
7. Campbell, KM. Rule your data with the Link King° (a SAS/AF® application for record linkage and unduplication). In: Proceedings of SAS Users Group International. April 10-13, 2005, Philadelphia, PA. Paper 020-30.Google Scholar
8. Dudeck, MA, Weiner, LM, Malpied, PJ, Edwards, JR, Peterson, KD, Sievert, DM. Risk adjustment for healthcare facility-onset C. difficile and MRSA bacteremia laboratory-identified event reporting in NHSN. National Healthcare Safety Network website. http://www.cdc.gov/nhsn/PDFs/mrsa-cdi/RiskAdjustment-MRSA-CDI.pdf. Accessed April 23, 2013.Google Scholar
9. Simor, AE. Diagnosis, management, and prevention of Clostridium difficile infection in long-term care facilities: a review. J Am Geriatr Soc 2010;58:15561564.Google Scholar
10. Zilderberg, MD, Tillotson, GS, McDonald, LC. Clostridium difficile infections among hospitalized children, United States, 1997-2006. Emerg Infect Dis 2010;16:604609.Google Scholar
11. Huang, SS, Avery, TR, Song, Y, et al. Quantifying interhospital patient sharing as a mechanism for infectious disease spread. Infect Control Hosp Epidemiol 2010;31:11601169.Google Scholar
12. Hospital-acquired infections—New York State 2011. New York State Department of Health website. http://www.health.state.ny.us/statistics/facilities/hospital/hospital_acquired_infections/. Published 2012. Accessed February 18, 2012.Google Scholar