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Which Comorbid Conditions Should We Be Analyzing as Risk Factors for Healthcare-Associated Infections?

Published online by Cambridge University Press:  29 December 2016

Anthony D. Harris*
University of Maryland School of Medicine, Baltimore, Maryland
Lisa Pineles
University of Maryland School of Medicine, Baltimore, Maryland
Deverick Anderson
Duke University Medical Center, Department of Medicine, Division of Infectious Diseases, Durham, North Carolina Duke Center for Antimicrobial Stewardship and Infection Prevention, Durham, North Carolina
Keith F. Woeltje
Department of Medicine, Washington University Medical Center, St Louis, Missouri BJC HealthCare, St Louis, Missouri
William E. Trick
Rush University Medical Center, Chicago, Illinois Cook County Health and Hospitals System, Chicago, Illinois
Keith S. Kaye
Division of Infectious Diseases, Detroit Medical Center, Wayne State University, Detroit, Michigan
Deborah S. Yokoe
Department of Medicine, Brigham & Women’s Hospital, Boston, Massachusetts
Ann-Christine Nyquist
Children’s Hospital Colorado, Aurora, Colorado
David P. Calfee
Weill Cornell Medicine, New York, New York
Surbhi Leekha
University of Maryland School of Medicine, Baltimore, Maryland
Address correspondence to Anthony D. Harris, MD MPH, 10 S. Pine St, MSTF 330, Baltimore, MD 21201 (



To determine which comorbid conditions are considered causally related to central-line associated bloodstream infection (CLABSI) and surgical-site infection (SSI) based on expert consensus.


Using the Delphi method, we administered an iterative, 2-round survey to 9 infectious disease and infection control experts from the United States.


Based on our selection of components from the Charlson and Elixhauser comorbidity indices, 35 different comorbid conditions were rated from 1 (not at all related) to 5 (strongly related) by each expert separately for CLABSI and SSI, based on perceived relatedness to the outcome. To assign expert consensus on causal relatedness for each comorbid condition, all 3 of the following criteria had to be met at the end of the second round: (1) a majority (>50%) of experts rating the condition at 3 (somewhat related) or higher, (2) interquartile range (IQR)≤1, and (3) standard deviation (SD)≤1.


From round 1 to round 2, the IQR and SD, respectively, decreased for ratings of 21 of 35 (60%) and 33 of 35 (94%) comorbid conditions for CLABSI, and for 17 of 35 (49%) and 32 of 35 (91%) comorbid conditions for SSI, suggesting improvement in consensus among this group of experts. At the end of round 2, 13 of 35 (37%) and 17 of 35 (49%) comorbid conditions were perceived as causally related to CLABSI and SSI, respectively.


Our results have produced a list of comorbid conditions that should be analyzed as risk factors for and further explored for risk adjustment of CLABSI and SSI.

Infect Control Hosp Epidemiol 2017;38:449–454

Original Articles
© 2017 by The Society for Healthcare Epidemiology of America. All rights reserved 

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