Cost-effectiveness of supplementing a broth-enriched culture test with the Xpert meticillin-resistant Staphylococcus aureus (MRSA) assay for screening inpatients at high risk of MRSA

Background: Meticillin-resistant Staphylococcus aureus (MRSA) represents a considerable challenge for health care in terms of complications and costs. Whilst bacteriological culture remains the most common method for detecting MRSA, the polymerase-chain-reaction-based Xpert MRSA assay was introduced to Ulleval Oslo University Hospital, Norway in 2009. Aim: To estimate the cost-effectiveness of supplementing a broth-enriched culture test with the Xpert MRSA assay in comparison with using the culture test alone as part of an active surveillance strategy. Methods: A decision-tree model was developed to compare the current strategy (broth-enriched culture test) with two new strategies using the Xpert MRSA assay (daytime and 24 h). Costs and outcomes (length of pre-emptive isolation, number of unavailable room-hours, quality of life) were measured. Findings: The current strategy was more expensive (NOK16,984 per patient) than the daytime Xpert strategy and 24 h Xpert strategy (NOK7360 and NOK3690 per patient, respectively). The new strategies reduced the length of pre-emptive isolation per patient (by 43.9 h and 57.5 h for the daytime Xpert strategy and 24 h Xpert strategy, respectively), and also the number of unavailable room-hours per case (by 57.1 h and 77.7 h, respectively). The improvement in patients' quality-adjusted life years (QALYs) was nominal (2.4*10(-4) and 3.0*10(-4) QALYs per patient for the daytime Xpert strategy and 24 h Xpert strategy, respectively). The sensitivity analyses indicated that these results were robust to reasonable changes in the model parameters. Conclusions: The 24 h Xpert strategy appears to be the best strategy for active surveillance as it reduces costs and unfavourable outcomes compared with the other strategies, while improving favourable outcomes under reasonable assumptions. (C) 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.