Perspective:

Since 1955, the AHA has issued guidelines on AP to reduce the risk of IE among people undergoing IDPs. However, in the absence of clinical trials documenting the efficacy of AP in reducing IE risk, and with stated concern for adverse drug reactions and the promotion of antibiotic resistance, AHA and European Society of Cardiology recommendations currently limit AP use to those at the highest risk, and current United Kingdom recommendations support the complete cessation of AP. Although previous IE case-crossover studies have been small and lacked statistical power, this study, relying on large administrative databases, demonstrated that AP use prior to IDPs (especially extractions or other oral-surgical procedures) was associated with a significant reduction in the incidence of IE in high-risk individuals. Study limitations include the reliance on administrative databases with their inherent limitations and that probably are not representative of the whole US population, and the inability of using those databases to discern the microbiological causes of IE.

This study refers to patients based on their risk of IE; whereas AHA guideline recommendations for AP very specifically are based on a high risk of IE adverse outcomes, not a high risk of developing IE. Because this study addressed whether AP affected the likelihood of a diagnosis of IE and not whether AP affected the outcome of IE, the study results seem to support broadening AHA recommendations to include AP for all patients at high lifetime risk of developing IE rather than restricting AP only to those at the highest risk of an adverse outcome. Although this study did not show a reduction in the incidence of IE among those at moderate risk, this may be a function of study power, and in the absence of data supporting adverse drug reactions or antibiotic resistance promoted by AP, re-broadening AP recommendations to include all individuals at increased risk of IE might be appropriate.