Importance of the surveillance method: national prevalence studies on nosocomial infections and the limits of comparison.
OBJECTIVE
To demonstrate the limits of comparison of national prevalence rates of nosocomial infections.


METHODS
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.
Institute of Hygiene, Free University, Berlin, Germany. pgastmei@charite.de
P
P
Gastmeier
G
G
Kampf
N
N
Wischnewski
M
M
Schumacher
F
F
Daschner
H
H
Rüden
D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D003430:Cross-Sectional Studies; D005060:Europe / Q000453:epidemiology; D006276:Health Facility Size / Q000706:statistics & numerical data; D006801:Humans; D017053:Infection Control / Q000379:methods*; D007755:Laboratories, Hospital / Q000706:statistics & numerical data; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence; D015203:Reproducibility of Results; D012107:Research Design / Q000592:standards*