Use of multiple antimicrobial drugs by clinical patients: a prognostic index of hospital mortality?

PURPOSE To quantify the use of multiple and prolonged antibiotics and anti-infective drug therapy in clinical patients in a 144-bed hospital. METHODS Adult patients (2,790 patients with 3,706 admissions over a period of 19 months) were investigated prospectively regarding treatment with anti-infective agents. The mean age was 57.4 (range, 18.8-97 years), and 54.3% were females (2012). RESULTS Hospital stay was 5.5 (6.7 days (range, 2-226 days), with duration up to 10 days for 91.9% of the subjects. Antibiotics or other agents were administered to 1,166 subjects (31.5%), 325 (8.8%) required assistance in the ICU, and a total of 141 (3.8%) died. The association between anti-infective drug therapy and hospital mortality was statistically significant (P < .01) with a strong linear correlation (r = 0.902, P = .014). The quantity of prescribed antimicrobial drugs, age, and need for ICU assistance were independent variables for death by logistic regression analysis. The odds ratio for anti-infective drug therapy was 1.341 (1.043 to 1.725); for age, 1.042 ( 1.026 to 1.058); and for stay in the ICU, 11.226 ( 6.648 to 18.957). CONCLUSIONS 1) The use of large amounts of anti-infective drug therapy was associated with higher hospital mortality according to both univariate and logistic regression analysis; 2) The adverse influence was less marked than that of hospitalization in ICU but of a similar order of magnitude as age; 3) Further studies should elucidate whether infectious foci, noninfectious morbidity, or drug effects underlie this undesirable concurrence.