Does catheter-associated urinary tract infection increase mortality in critically ill patients?

OBJECTIVE To produce an accurate estimate of the association between catheter-associated urinary tract infection (UTI) and intensive care unit (ICU) and hospital mortality, controlling for major confounding factors. DESIGN Nested case-control study in a multicenter cohort (the OutcomeRea database). SETTING Twelve French medical or surgical ICUs. METHODS All patients admitted between January 1997 and August 2005 who required the insertion of an indwelling urinary catheter. Patients who developed catheter-associated UTI (ie, case patients) were matched to control patients on the basis of the following criteria: sex, age (+/- 10 years), SAPS (Simplified Acute Physiology Score) II score (+/- 10 points), duration of urinary tract catheterization, and presence or absence of diabetes mellitus. The association of catheter-associated UTI with ICU and hospital mortality was assessed by use of conditional logistic regression. RESULTS Of the 3,281 patients who had an indwelling urinary catheter, 298 (9%) developed at least 1 episode of catheter-associated UTI. The incidence density of catheter-associated UTI was 12.9 infections per 1,000 catheterization-days. Crude ICU mortality rates were higher among patients with catheter-associated UTI, compared with those without catheter-associated UTI (32% vs 25%, P=.02); the same was true for crude hospital mortality rates (43% vs 30%, P<.01). After matching and adjustment, catheter-associated UTI was no longer associated with increased mortality (ICU mortality: odds ratio [OR], 0.846 [95% confidence interval {CI}, 0.659-1.086]; P=.19 and hospital mortality: OR, 0.949 [95% CI, 0.763-1.181]; P=.64). CONCLUSION After carefully controlling for confounding factors, catheter-associated UTI was not found to be associated with excess mortality among our population of critically ill patients in either the ICU or the hospital.