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Denominator Doesn’t Matter: Standardizing Healthcare-Associated Infection Rates by Bed Days or Device Days

Published online by Cambridge University Press:  18 March 2015

Molly J. Horstman*
Affiliation:
Center for Innovations in Quality, Effectiveness, and Safety (IQuESt); Michael E. DeBakey VA Medical Center, Houston, TexasSection of General Internal Medicine, Department of Medicine, Baylor College of Medicine, Houston, Texas
Yu-Fang Li
Affiliation:
Operational Analytics and Reporting, Office of Informatics and Analytics, Veterans Health Administration, Department of Veterans Affairs, Washington, DCBehavioral Nursing and Health Systems, University of Washington, Seattle, Washington
Peter L. Almenoff
Affiliation:
Operational Analytics and Reporting, Office of Informatics and Analytics, Veterans Health Administration, Department of Veterans Affairs, Washington, DCOffice of the Secretary, Department of Veterans Affairs, Washington, DCCenter for Innovation, Department of Veterans Affairs, Washington, DCDepartment of Biomedical and Health Informatics and Department of Medicine, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri
Ron W. Freyberg
Affiliation:
Operational Analytics and Reporting, Office of Informatics and Analytics, Veterans Health Administration, Department of Veterans Affairs, Washington, DC
Barbara W. Trautner
Affiliation:
Center for Innovations in Quality, Effectiveness, and Safety (IQuESt); Michael E. DeBakey VA Medical Center, Houston, TexasSection of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, TexasDepartment of Surgery, Baylor College of Medicine, Houston, Texas
*
Address all correspondence to Molly J. Horstman, MD, 2002 Holcombe Boulevard, Center for Innovations in Quality, Effectiveness, and Safety, Houston, Texas 77030 (molly.horstman@bcm.edu).
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Abstract

OBJECTIVE

To examine the impact on infection rates and hospital rank for catheter-associated urinary tract infection (CAUTI), central line-associated bloodstream infection (CLABSI), and ventilator-associated pneumonia (VAP) using device days and bed days as the denominator

DESIGN

Retrospective survey from October 2010 to July 2013

SETTING

Veterans Health Administration medical centers providing acute medical and surgical care

PATIENTS

Patients admitted to 120 Veterans Health Administration medical centers reporting healthcare-associated infections

METHODS

We examined the importance of using device days and bed days as the denominator between infection rates and hospital rank for CAUTI, CLABSI, and VAP for each medical center. The relationship between device days and bed days as the denominator was assessed using a Pearson correlation, and changes in infection rates and device utilization were evaluated by an analysis of variance.

RESULTS

A total of 7.9 million bed days were included. From 2011 to 2013, CAUTI decreased whether measured by device days (2.32 to 1.64, P=.001) or bed days (4.21 to 3.02, P=.006). CLABSI decreased when measured by bed days (1.67 to 1.19, P=.04). VAP rates and device utilization ratios for CAUTI, CLABSI, and VAP were not statistically different across time. Infection rates calculated with device days were strongly correlated with infection rates calculated with bed days (r=0.79–0.94, P<.001). Hospital relative performance measured by ordered rank was also strongly correlated for both denominators (r=0.82–0.96, P<.001).

CONCLUSIONS

These findings suggest that device days and bed days are equally effective adjustment metrics for comparing healthcare-associated infection rates between hospitals in the setting of stable device utilization.

Infect Control Hosp Epidemiol 2015;00(0): 1–7

Information

Type
Original Articles
Copyright
© 2015 by The Society for Healthcare Epidemiology of America. All rights reserved 
Figure 0

TABLE 1Total number of Infections, Device Days, and Bed Days Stratified by Year and Hospital Complexity

Figure 1

FIGURE 1Infection rates and device utilization ratio by complexity level and year. NOTE. Complexity level 3 facilities were not shown in graphs for VAP due to the small number of facilities in this category in this study.

Figure 2

TABLE 2Hospital-Level Infection Rate and Device Utilization Ratio

Figure 3

TABLE 3Pearson Correlation Coefficients for Infection Rates and Hospital Rankings Derived Using Device Days Versus Bed Days as the Denominator