A systematic review and economic model of switching from non-glycopeptide to glycopeptide antibiotic prophylaxis for surgery.

OBJECTIVES: To determine whether there is a level of methicillin-resistant Staphylococcus aureus (MRSA) prevalence at which a switch from non-glycopeptide to glycopeptide antibiotics for routine prophylaxis is indicated in surgical environments with a high risk of MRSA infection. DATA SOURCES: Major electronic databases were searched up to September 2005. REVIEW METHODS: The effectiveness review included controlled clinical trials comparing a glycopeptide with an alternative antibiotic regimen that reported effectiveness and/or adverse events. Controlled observational studies were also included for adverse events. The cost-effectiveness review included economic evaluations comparing glycopeptide prophylaxis with any alternative comparator. Study validity was assessed using standard checklists. The supplementary economic reviews assessed evaluations of non-glycopeptide antibiotic prophylaxis; evaluations where antibiotic resistance is a problem; methods of modelling resistance in infectious diseases; and developing a conceptual framework. An indicative decision analytic model was developed to compare vancomycin with a cephalosporin and with a combination of vancomycin and cephalosporin, using hip arthroplasty as an exemplar. Available data on, for example, surgical site infection (SSI) rates, MRSA rates, effectiveness of the antibiotics, were incorporated into the model. Costs were estimated from the perspective of the NHS. RESULTS: The effectiveness review included 16 randomised controlled trials, with a further three studies included for adverse events only. There was no evidence that glycopeptides were more effective than non-glycopeptides in preventing SSIs. Most of the trials did not report either the baseline prevalence of MRSA at the participating surgical units or MRSA infections as an outcome. The cost-effectiveness review included five economic evaluations of glycopeptide prophylaxis. Only one study incorporated health-related quality of life and undertook a cost-utility analysis. None of the studies was undertaken in the UK and none explicitly modelled antibiotic resistance. The supplementary reviews provided few insights into how to assess cost-effectiveness in the context of resistance. No studies modelled cost-effectiveness alongside epidemiological models of resistance. There was little information regarding the impact of surgical infections on costs post-discharge and patient quality of life. The lack of available clinical evidence limited the development of the cost-effectiveness model and meant that the modelling could only be indicative in nature. The model can be used to show the threshold baseline risk at which the use of vancomycin as prophylaxis might be cost-effective (the model did not include teicoplanin). The indicative model suggests that the baseline risk of MRSA can be fairly modest at below the national average and it would still appear cost-effective to use glycopeptide prophylaxis. The model indicates that the use of glycopeptides as a form of prophylaxis in addition to a treatment for MRSA infections is unlikely to decrease the total usage and hence reduce the risk of future problems with glycopeptide-resistant bacteria. CONCLUSIONS: There is insufficient evidence to determine whether there is a threshold prevalence of MRSA at which switching from non-glycopeptide to glycopeptide antibiotic prophylaxis might be clinically effective and cost-effective. Future research needs to address the complexities of decision-making relating to the prevention of MRSA and infection control in general. Research including evidence synthesis and decision modelling comparing a full range of interventions for infection control, which extends to other infections, not just MRSA, is needed. A long-term research programme to predict the pattern of drug resistance and its implications for future costs and health is also needed.