Risk factors for death due to nosocomial infection in intensive care unit patients:: Findings from the krankenhaus infektions surveillance system

Objective. To determine risk factors for death among patients with nosocomial pneumonia and patients with primary bloodstream infections ( BSI) in intensive care units ( ICUs). Design. Prospective cohort study. Setting. Data collected from January 1997 through June 2003 from ICUs registered with the Krankenhaus Infektions Surveillance System in Germany. Patients. A total of 8,432 patients with nosocomial pneumonia from 202 ICUs and 2,759 patients with nosocomial primary BSI from 190 ICUs. Methods. The following risk factors were considered in the analysis: age, sex, time in the ICU before onset of infection, type of ICU, type and size of hospital, intubation, central venous catheter use, total parenteral nutrition, and type of pathogen. Results. A total of 750 patients ( 8.9%) with nosocomial pneumonia and 302 patients ( 10.9%) with nosocomial primary BSI died. Multiple logistic regression analysis identified treatment in a medical or surgical ICU ( odds ratio [ OR], 1.55 [ 95% confidence interval {CI}, 1.32-1.82]) or a hospital with more than 1,000 beds ( OR, 2.14 [ 95% CI, 1.81-2.56]), age older than 65 years ( OR, 1.54 [ 95% CI, 1.31-1.81]), and infection with methicillin-resistant Staphylococcus aureus ( OR, 2.39 [ 95% CI, 1.81-3.12]) or multidrug-resistant Pseudomonas aeruginosa ( OR, 3.00 [ 95% CI, 1.90-4.63]) as independent determinants of death from nosocomial pneumonia. Age older than the median of 63 years ( OR, 1.44 [ 95% CI, 1.12-1.86]) and methicillin-resistant S. aureus as the causative agent ( OR, 2.98 [ 95% CI, 1.81-5.82]) were both associated with increased mortality from primary BSI. The types of infecting pathogens, particularly those resistant to multiple drugs, were also strong outcome predictors among ICU patients. Conclusions. The study results underline the need for further investigations of the role of antimicrobial resistance in the outcome of patients with nosocomial pneumonia and patients with primary BSI.