Case-mix adjustment approach to benchmarking prevalence rates of nosocomial infection in hospitals in Cyprus and Greece.
OBJECTIVE
To examine the effect of heterogeneous case mix for a benchmarking analysis and interhospital comparison of the prevalence rates of nosocomial infection.


METHODS
Cross-sectional survey.


METHODS
Eleven hospitals located in Cyprus and in the region of Crete in Greece.


METHODS
The survey included all inpatients in the medical, surgical, pediatric, and gynecology-obstetrics wards, as well as those in intensive care units. Centers for Disease Control and Prevention criteria were used to define nosocomial infection. The information collected for all patients included demographic characteristics, primary admission diagnosis, Karnofsky functional status index, Charlson comorbidity index, McCabe-Jackson severity of illness classification, use of antibiotics, and prior exposures to medical and surgical risk factors. Outcome data were also recorded for all patients. Case mix-adjusted rates were calculated by using a multivariate logistic regression model for nosocomial infection risk and an indirect standardization method.Results. The overall prevalence rate of nosocomial infection was 7.0% (95% confidence interval, 5.9%-8.3%) among 1,832 screened patients. Significant variation in nosocomial infection rates was observed across hospitals (range, 2.2%-9.6%). Logistic regression analysis indicated that the mean predicted risk of nosocomial infection across hospitals ranged from 3.7% to 10.3%, suggesting considerable variation in patient risk. Case mix-adjusted rates ranged from 2.6% to 12.4%, and the relative ranking of hospitals was affected by case-mix adjustment in 8 cases (72.8%). Nosocomial infection was significantly and independently associated with mortality (adjusted odds ratio, 3.6 [95% confidence interval, 2.1-6.1]).


CONCLUSIONS
The first attempt to rank the risk of nosocomial infection in these regions demonstrated the importance of accounting for heterogeneous case mix before attempting interhospital comparisons.
Kritsotakis
Evangelos I
EI
Laboratory of Clinical Bacteriology, Parasitology, Zoonoses, and Geographical Medicine, University of Crete, Greece.
Dimitriadis
Ioannis
I
Roumbelaki
Maria
M
Vounou
Emelia
E
Kontou
Maria
M
Papakyriakou
Panikos
P
Koliou-Mazeri
Maria
M
Varthalitis
Ioannis
I
Vrouchos
George
G
Troulakis
George
G
Gikas
Achilleas
A
D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D003535:Cyprus / Q000453:epidemiology; D005260:Female; D006115:Greece / Q000453:epidemiology; D006742:Hospital Bed Capacity; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015995:Prevalence; D020379:Risk Adjustment; D012307:Risk Factors
D000900:Anti-Bacterial Agents