LAUSR

tine antibiotic prophylaxis with the new guidelines. A total of 4 case–control studies, 1 retrospective cohort and 10 time series studies were appropriate for inclusion. Three of these studies excluded children. Although antibiotic prophylaxis significantly reduces the rate of bacteraemia after dental procedures (risk ratio = 0.53 (95% confidence interval (CI) 0.49, 0.57; P < 0.01)), bacteraemia is not considered a good surrogate measure for infective endocarditis. The rate of infective endocarditis in the case– control studies showed a non-significant trend for reduction: odds ratio = 0.59 (95% CI 0.27, 1.30; P = 0.14)). While concluding there is a need for high-quality studies to address this question, the current poor quality evidence supports advising prophylaxis for patients with the highest risk as a ‘pragmatic and justified approach’.