Quantification of risk factors in hospital infection at a surgical service.

In this paper we have analyzed several risk factors for developing nosocomial infections at a Surgical Service of the Hospital Clinico Universitario "San Cecilio", based on a retrospective follow-up program designed specifically for this study. Of all patients admitted to the Service from January 1 to June 17, 1987, we examined the following variables: age, sex, cause of admission, emergency or non-emergency admission, operation and related variables. The overall rate of nosocomial infections was 16.46%. The most significant risk factors we found were "operation", which had a linear correlation coefficient of 0.929 (p less than 0.01) with hospital infection when stratified by its length, "advanced age" (greater than 60 years old), especially in non-operated patients, and chemoprophylaxis. Such risk factors were ascertained taking into account the confounding effect produced by the variables studied in this survey.