Nosocomial infections and outcome of critically ill elderly patients after surgery

Background: The relation between older age and nosocomial infection and mortality in the intensive care unit (ICU) is still a controversial issue. Methods: The authors prospectively studied 406 patients admitted to a surgical ICU, 106 of whom were more than 75 yr old. Information concerning ICU-acquired nosocomial infections, severity of illness, therapeutic activity, and hospital outcome was collected. A Cox proportional hazard analysis was used to evaluate potential risk factors for ICU-acquired nosocomial infections, ICU, and hospital death. Results: During their ICU stay, 23 elderly patients experienced 40 nosocomial infections, 28 "young" patients (< 60 yr) experienced 54 nosocomial infections, and 52 "intermediate age" patients (60-75 yr) experienced 98 nosocomial infections. Incidence density of nosocomial infections was 4.9% patient days for elderly patients, 4.7% for young patients, and 6.0% for Intermediate age patients (no significance). The frequency distribution of the various microorganisms isolated was similar between the three groups. Compared with younger patients, elderly patients had a higher Acute Physiology and Chronic Health Evaluation II score and a higher ICU and hospital mortality rate. Despite a higher level of severity of illness, elderly patients had a reduction of therapeutic activity. However, Cox proportional hazard analysis showed that age more than 75 yr was not a risk factor for ICU-acquired nosocomial infection, ICU, or hospital death. Conclusions: In patients referred to a surgical ICU after a surgical procedure, age more than 75 yr by itself does not appear to he a significant predictor of ICU-acquired nosocomial infection or mortality rate during the ICU stay. However, it appears that patients more than 60 yr have a higher incidence of nosocomial infection in ICU.