The cost-effectiveness of antibiotic prophylaxis for patients at risk of infective endocarditis

Background

In March 2008, the National Institute for Health and Care Excellence (NICE) recommended stopping antibiotic prophylaxis (AP) for those at risk of infective endocarditis (IE) undergoing dental procedures in the UK, citing a lack of evidence of efficacy and cost-effectiveness. We have performed a new economic-evaluation of AP based on contemporary estimates of efficacy, adverse events and resource implications.

Methods

A decision analytic cost-effectiveness model was used. Health service costs and benefits (measured as Quality Adjusted Life Years, QALYs) were estimated. Rates of IE before and after the NICE guidance were available to estimate prophylactic efficacy. AP adverse event rates were derived from recent UK data and resource implications were based on English Hospital Episode Statistics.

Results

AP was less costly and more effective than no AP for all patients at risk of IE. The results are sensitive to AP efficacy, but efficacy would have to be substantially lower for AP not to be costeffective. AP was even more cost-effective in patients at high-risk of IE. Only a marginal reduction in annual IE rates (1.44 cases in high-risk and 33 cases in all at-risk patients) would be required for AP to be considered cost-effective at £20,000 ($26,600) per QALY. Annual cost savings of £5.5-8.2m ($7.3-10.9m) and health gains >2,600 QALYs could be achieved from reinstating AP in England.

Conclusions

AP is cost-effective for preventing IE, particularly in those at high-risk. These findings support the cost-effectiveness of guidelines recommending AP use in high-risk individuals.