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.