Antibiotic prophylaxis for preventing bacterial endocarditis following dental procedures: a Cochrane review

BACKGROUND Infective endocarditis is a severe infection arising in the lining of the chambers of the heart. It can be caused by fungi, but most often is caused by bacteria. Many dental procedures cause bacteraemia, which could lead to bacterial endocarditis in a small proportion of people. The incidence of bacterial endocarditis is low, but it has a high mortality rate. Guidelines in many countries have recommended that antibiotics be administered to people at high risk of endocarditis prior to invasive dental procedures. However, guidance by the National Institute for Health and Care Excellence (NICE), in England and Wales states, that antibiotic prophylaxis against infective endocarditis is not recommended routinely for people undergoing dental procedures. OBJECTIVES Primary objective. To determine whether prophylactic antibiotic administration, compared to no antibiotic administration or placebo, before invasive dental procedures in people at risk or at high risk of bacterial endocarditis, influences mortality, serious illness or the incidence of endocarditis. Secondary objectives. To determine whether the effect of dental antibiotic prophylaxis differs in people with different cardiac conditions predisposing them to increased risk of endocarditis, and in people undergoing different high risk dental procedures. Harms. The harms of prophylaxis with single antibiotic doses, such as with penicillin (amoxicillin 2 g or 3 g) before invasive dental procedures, compared with no antibiotic or placebo, were assessed. SEARCH METHODS An information specialist searched four bibliographic databases up to 10 May 2021 and used additional search methods to identify published, unpublished and on going studies. SELECTION CRITERIA Due to the low incidence of bacterial endocarditis, cohort and case-control studies with suitably matched control or comparison groups were included. The intervention was antibiotic prophylaxis, compared to no antibiotic prophylaxis or placebo, before a dental procedure in people with an increased risk of bacterial endocarditis. Cohort studies would need to follow at-risk individuals and assess outcomes following any invasive dental procedures, grouping participants according to whether or not they had received prophylaxis. Case-control studies would need to match people who had developed endocarditis after undergoing an invasive dental procedure (and who were known to be at increased risk before undergoing the procedure) with those at similar risk who had not developed endocarditis. DATA COLLECTION AND ANALYSIS Two review authors independently screened search records, selected studies for inclusion, assessed the risk of bias in the included study and extracted data from the included study. As an author team, the certainty of the evidence identified for the main comparison and key outcomes were judged using GRADE criteria. MAIN RESULTS No randomised controlled trials (RCTs), controlled clinical trials (CCTs) or cohort studies were included, but one case-control study met the inclusion criteria. The trial authors collected information on 48 people who had contracted bacterial endocarditis over a specific two-year period and had undergone a medical or dental procedure with an indication for prophylaxis within the past 180 days. These people were matched to a similar group of people who had not contracted bacterial endocarditis. All study participants had undergone an invasive medical or dental procedure. The two groups were compared to establish whether those who had received preventive antibiotics (penicillin) were less likely to have developed endocarditis. The authors found no significant effect of penicillin prophylaxis on the incidence of endocarditis. No data on other outcomes were reported. The level of certainty about the evidence is very low. AUTHORS' CONCLUSIONS There remains no clear evidence about whether antibiotic prophylaxis is effective or ineffective against bacterial endocarditis in at-risk people who are about to undergo an invasive dental procedure. It is not possible to determine whether the potential harms and costs of antibiotic administration outweigh any beneficial effect. Ethically, practitioners should discuss the potential benefits and harms of antibiotic prophylaxis with their patients before a decision is made about administration.