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

Summary 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 Ullevål 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.