OBJECTIVES: To report the pooled results of seven prevalence surveys of hospital-acquired infections conducted between

OBJECTIVE:To model the economic costs of hospitalacquired infections (HAIs) in New Zealand, by type of HAL DESIGN: Monte Carlo simulation model. SETTING: Auckland District Health Board Hospitals (DHBH), the largest publicly funded hospital group in New Zealand supplying secondary and tertiary services. Costs are also estimated for predicted HAIs in admissions to all hospitals in New Zealand.PATIENTS: All adults admitted to general medical and general surgical services.METHOD: Data on the number of cases of HAI were combined with data on the estimated prolongation of hospital stay due to HAI to produce an estimate of the number of bed days attributable to HAI. A cost per bed day value was applied to provide an estimate of the economic cost. Costs were estimated for predicted infections of the urinary tract, surgical wounds, the lower and upper respiratory tracts, the bloodstream, and other sites, and for cases of multiple sites of infection. Sensitivity analyses were undertaken for input variables. RESULTS:The estimated costs of predicted HAIs in medical and surgical admissions to Auckland DHBH were $10.12 (US $4.56) million and $8.64 (US $3.90) million, respectively. They were $51.35 (US $23.16) million and $85.26 (US $38.47) million, respectively, for medical and surgical admissions to all hospitals in New Zealand.CONCLUSIONS: The method used produces results that are less precise than those of a specifically designed study using primary data collection, but has been applied at a lower cost. The estimated cost of HAIs is substantial, but only a proportion of infections can be avoided. Further work is required to identify the most cost-effective strategies for the prevention of HAI (Infect Control Hosp Epidemiol 2003;24:214-223 27 Israel, 28 and France. 29 The findings illustrate the impact of the disease on the acute and the community healthcare sectors, patients, caregivers, and the wider economy. These data have been used to raise the profile of hospital-acquired infection among policy makers 30 and, if appropriately derived, they proxy the value of the potential economic benefits that result from programs that prevent hospitalacquired infection. 31 Although the prevalence of hospital-acquired infections in New Zealand hospitals and estimates of the cumulative incidence have been reported, 3233 no estimates of the economic cost of these infections have been published. The purpose of this article is to model the cost attributable to hospital-acquired infections occurring among adult patients admitted to the general medical and surgical services of Auckland District Health Board Hospitals for calendar year 1999 and patients admitted to all hospitals in New Zealand for the 1998-1999 financial year.The cost analysis includes only hospital costs because recent work has shown that 93.4% of the total costs of hospital-acquired infection fall on the hospital sector 34 and assessing the remaining costs, those that fall on primary and community care services and the patients themselves, would involve extensi...