Intensive care acquired infection is an independent risk factor for hospital mortality: a prospective cohort study

Introduction The aim of this study was to elucidate the impact of intensive care unit (ICU)-acquired infection on hospital mortality. Methods Patients with a longer than 48 hour stay in a mixed 10 bed ICU in a tertiary-level teaching hospital were prospectively enrolled between May 2002 and June 2003. Risk factors for hospital mortality were analyzed with a logistic regression model. Results Of 335 patients, 80 developed ICU-acquired infection. Among the patients with ICU-acquired infections, hospital mortality was always higher, regardless of whether or not the patients had had infection on admission ( infection on admission group (IAG), 35.6% versus 17%, p = 0.008; and no-IAG, 25.7% versus 6.1%, p = 0.023). In IAG ( n = 251), hospital stay was also longer in the presence of ICU-acquired infection ( median 31 versus 16 days, p < 0.001), whereas in no-IAG ( n = 84), hospital stay was almost identical with and without the presence of ICU-acquired infection ( 18 versus 17 days). In univariate analysis, the significant risk factors for hospital mortality were: Acute Physiology and Chronic Health Evaluation (APACHE) II score > 20, sequential organ failure assessment ( SOFA) score > 8, ICU-acquired infection, age >= 65, community-acquired pneumonia, malignancy or immunosuppressive medication, and ICU length of stay > 5 days. In multivariate logistic regression analysis, ICU-acquired infection remained an independent risk factor for hospital mortality after adjustment for APACHE II score and age ( odds ratio ( OR) 4.0 (95% confidence interval (CI): 2.0 - 7.9)) and SOFA score and age ( OR 2.7 ( 95% CI: 2.9 - 7.6)). Conclusion ICU-acquired infection was an independent risk factor for hospital mortality even after adjustment for the APACHE II or SOFA scores and age.