Clostridium difficile in the intensive care unit: epidemiology, costs, and colonization pressure.

OBJECTIVE: To evaluate the epidemiology, outcomes, and importance of Clostridium difficile colonization pressure (CCP) as a risk factor for C. difficile-associated disease (CDAD) acquisition in intensive care unit (ICU) patients. DESIGN: Secondary analysis of data from a 30-month retrospective cohort study. SETTING: A 19-bed medical ICU in a midwestern tertiary care referral center. PATIENTS: Consecutive sample of adult patients with a length of stay of 24 hours or more between July 1, 1997, and December 31, 1999. RESULTS: Seventy-six (4%) of 1,872 patients were identified with CDAD; 40 (53%) acquired CDAD in the ICU, for an incidence of 3.2 cases per 1,000 patient-days. Antimicrobial therapy, enteral feeding, mechanical ventilation, vancomycin-resistant enterococci (VRE) colonization or infection, and CCP (5.5 vs 2.0 CDAD case-days of exposure for patients with acquired CDAD vs no CDAD; P=.001) were associated with CDAD acquisition in the univariate analysis. Only VRE colonization or infection (45% of patients with acquired CDAD vs 16% of patients without CDAD; adjusted odds ratio, 2.76 95% confidence interval, 1.36-5.59]) and a CCP of more than 30 case-days of exposure (20% with acquired CDAD vs 2% with no CDAD; adjusted odds ratio, 3.77 95% confidence interval, 1.14-12.49]) remained statistically significant in the multivariable analysis. Lengths of stay (6.1 vs 3.0 days; P<.001 by univariate analysis) and ICU costs ($11,353 vs $6,028; P<.001 by univariate analysis) were higher for patients with any CDAD than for patients with no CDAD. CONCLUSIONS: In this nonoutbreak setting, the CCP was an independent risk factor for acquisition of CDAD in the ICU at the upper range of exposure duration. Having CDAD in the ICU was a marker of excess healthcare use.