title: The effect of hospital-acquired infection with Clostridium difficile on length of stay in hospital.
abstract: BACKGROUND
  The effect of hospital-acquired infection with Clostridium difficile on length of stay in hospital is not yet fully understood. We determined the independent impact of hospital-acquired infection with C. difficile on length of stay in hospital.
  
  
  METHODS
  We conducted a retrospective observational cohort study of admissions to hospital between July 1, 2002, and Mar. 31, 2009, at a single academic hospital. We measured the association between infection with hospital-acquired C. difficile and time to discharge from hospital using Kaplan-Meier methods and a Cox multivariable proportional hazards regression model. We controlled for baseline risk of death and accounted for C. difficile as a time-varying effect.
  
  
  RESULTS
  Hospital-acquired infection with C. difficile was identified in 1393 of 136,877 admissions to hospital (overall risk 1.02%, 95% confidence interval [CI] 0.97%-1.06%). The crude median length of stay in hospital was greater for patients with hospital-acquired C. difficile (34 d) than for those without C. difficile (8 d). Survival analysis showed that hospital-acquired infection with C. difficile increased the median length of stay in hospital by six days. In adjusted analyses, hospital-acquired C. difficile was significantly associated with time to discharge, modified by baseline risk of death and time to acquisition of C. difficile. The hazard ratio for discharge by day 7 among patients with hospital-acquired C. difficile was 0.55 (95% CI 0.39-0.70) for patients in the lowest decile of baseline risk of death and 0.45 (95% CI 0.32-0.58) for those in the highest decile; for discharge by day 28, the corresponding hazard ratios were 0.74 (95% CI 0.60-0.87) and 0.61 (95% CI 0.53-0.68).
  
  
  CONCLUSIONS
  Hospital-acquired infection with C. difficile significantly prolonged length of stay in hospital independent of baseline risk of death.
authors.affiliation: Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ont. aforster@ohri.ca
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Forster
authors.forename: Monica
authors.initials: M
authors.lastname: Taljaard
authors.forename: Natalie
authors.initials: N
authors.lastname: Oake
authors.forename: Kumanan
authors.initials: K
authors.lastname: Wilson
authors.forename: Virginia
authors.initials: V
authors.lastname: Roth
authors.forename: Carl
authors.initials: C
authors.lastname: van Walraven
mesh_terms: D000368:Aged; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D005260:Female; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D015994:Incidence; D007902:Length of Stay / Q000639:trends*; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors