title: Excess Length of Stay Attributable to Clostridium difficile Infection (CDI) in the Acute Care Setting: A Multistate Model.
abstract: BACKGROUND
  Standard estimates of the impact of Clostridium difficile infections (CDI) on inpatient lengths of stay (LOS) may overstate inpatient care costs attributable to CDI. In this study, we used multistate modeling (MSM) of CDI timing to reduce bias in estimates of excess LOS.
  
  
  METHODS
  A retrospective cohort study of all hospitalizations at any of 120 acute care facilities within the US Department of Veterans Affairs (VA) between 2005 and 2012 was conducted. We estimated the excess LOS attributable to CDI using an MSM to address time-dependent bias. Bootstrapping was used to generate 95% confidence intervals (CI). These estimates were compared to unadjusted differences in mean LOS for hospitalizations with and without CDI.
  
  
  RESULTS
  During the study period, there were 3.96 million hospitalizations and 43,540 CDIs. A comparison of unadjusted means suggested an excess LOS of 14.0 days (19.4 vs 5.4 days). In contrast, the MSM estimated an attributable LOS of only 2.27 days (95% CI, 2.14-2.40). The excess LOS for mild-to-moderate CDI was 0.75 days (95% CI, 0.59-0.89), and for severe CDI, it was 4.11 days (95% CI, 3.90-4.32). Substantial variation across the Veteran Integrated Services Networks (VISN) was observed.
  
  
  CONCLUSIONS
  CDI significantly contributes to LOS, but the magnitude of its estimated impact is smaller when methods are used that account for the time-varying nature of infection. The greatest impact on LOS occurred among patients with severe CDI. Significant geographic variability was observed. MSM is a useful tool for obtaining more accurate estimates of the inpatient care costs of CDI.
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Vanessa W
authors.initials: VW
authors.lastname: Stevens
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Karim
authors.initials: K
authors.lastname: Khader
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Nelson
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Makoto
authors.initials: M
authors.lastname: Jones
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Rubin
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Brown
authors.affiliation: 4Veterans Health Administration,Methicillin-ResistantStaphylococcus aureus/Multidrug-Resistant Organisms Prevention Office,National Infectious Diseases Service,Lexington,Kentucky.
authors.forename: Martin E
authors.initials: ME
authors.lastname: Evans
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Tom
authors.initials: T
authors.lastname: Greene
authors.affiliation: 5Mental Illness Resource Education and Clinical Center (MIRECC),VA Capitol Health Care System,Baltimore,Maryland.
authors.forename: Eric
authors.initials: E
authors.lastname: Slade
authors.affiliation: 1VA Salt Lake City Health Care System,Salt Lake City,Utah.
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Samore
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015982:Bias; D016360:Clostridioides difficile; D004761:Enterocolitis, Pseudomembranous / Q000191:economics / Q000453:epidemiology*; D005260:Female; D006787:Hospitals, Veterans / Q000706:statistics & numerical data*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014481:United States