[Influence of nosocomial infection on mortality in an intensive care unit].

OBJECTIVE

To evaluate the association between nosocomial infections (NI) and the mortality of Intensive Care Unit (ICU) patients, adjusting for the effect on mortality of other predictive variables.

METHODS

Prospective study on 944 concurrent patients admitted for at least 24 hours in the ICU of a tertiary level hospital between February and November of 1994. The association between NI (diagnosed using CDC criteria) and mortality was studied using multivariable logistic regression.

RESULTS

The cummulative incidence of mortality in the ICU was 11.2% (CI95% = 9.9-12.5). This incidence was significantly higher in infected patients with a crude mortality relative risk of 2.2 (CI95% = 1.5-3.1). In the multivariable analysis, the effect of NI (global, pneumonias, of the urinary tract and bacteriemias) on adjusted mortality depended on the patient's Acute Pysiology and Chronic Health Evaluation II (APACHE II) score. With low APACHE II scores, NI was associated with an increased mortality risk. Conversely, with higher APACHE II scores, the relevance of NI as a determinant of mortality decreased and prognosis was mainly associated with the patient's severity of illness.

CONCLUSIONS

The association between NI and mortality, adjusting for other prognostic factors for mortality, is confirmed.