The impact of methicillin-resistant S. aureus on length of stay, readmissions and costs: a register based case-control study of patients hospitalized in Norway

A. Elizabeth S. Andreassen, Caroline M. Jacobsen, BirgitteFreiesleben de Blasio, Richard White, Ivar Sønbø Kristiansen, Petter Elstrøm

Patients with methicillin-resistant S. aureus (MRSA) are thought to incur additional costs for hospitals due to longer stay and contact isolation. The aim of this study was to assess the costs associated with MRSA in Norwegian hospitals. Analyses were based on data fromSouth-Eastern Norway for the year 2012 as registered in the Norwegian Surveillance System for Communicable Diseases and the Norwegian Patient Registry. We used a matched case-control method to compare MRSA diagnosed inpatients with non-MRSA inpatients in terms of length of stay, readmissions within 30 days from discharge, as well as the Diagnosis-Related Group (DRG) based costs. Norwegian patients with MRSA stayed on average 8 days longer in hospital than controls, corresponding to a ratio of mean duration of 2.08 (CI 95%, 1.75-2.47) times longer.A total of 14% of MRSA positive inpatients were readmitted compared to 10% among controls. However, the risk of readmission was not significantly higher for patients with MRSA. DRG based hospital costs were 0.37 (95% CI, 0.19-0.54) times higher among cases than controls, with a mean cost of EUR13,233(SD 26,899) and EUR7198(SD 18,159) respectively. The results of this study indicate that Norwegian patients with MRSA have longer hospital stays, and higher costs than those without MRSA.