Importance of the Surveillance Method: National Prevalence Studies on Nosocomial Infections and the Limits of Comparison

Abstract

Objective: To demonstrate the limits of comparison of national prevalence rates of nosocomial infections. Design and setting: Critical analysis of prevalence rates and methods of the Nosocomial Infections in Germany (NIDEP) study and other prevalence surveys with particular attention to the selection of patients, the qualification and training of the investigators, and the methods of identifying nosocomial infections. Results: The lowest prevalence rate was found in Germany (3.5 %), the highest in Belgium (9.3 %). These differences may not be accurate, because variations in methods allow for differing explanations. Conclusions: Because of numerous methodological factors, comparison of infection rates between countries should be avoided. In contrast to other prevalence studies, the methodology of the German-NIDEP study permits registration of only certain infections, which is the main reason for the low rate.