Antibiotic Prophylaxis Prescribing Changes and Endocarditis Incidence

Study Questions:

What are the changes in antibiotic prophylaxis prescribing and infective endocarditis (IE) incidence following the 2007 American Heart Association (AHA) recommendations in individuals at high, moderate, or unknown/low risk of infective endocarditis (IE)?


The investigators identified high-risk, moderate-risk, and unknown/low-risk individuals with linked prescription and Medicare or commercial health care data in the Truven Health Market Scan databases from May 2003 through August 2015 (198,522,665 enrollee-years of data). Antibiotic prophylaxis prescribing and IE incidence were evaluated by Poisson model analysis.


By August 2015, the 2007 recommendation change was associated with a significant 64% (95% confidence interval [CI], 59%-68%) estimated fall in antibiotic prophylaxis prescribing for moderate-risk individuals and a 20% (95% CI, 4%-32%) estimated fall for those at high risk. Over the same period, there was a barely significant 75% (95% CI, 3%-200%) estimated increase in IE incidence among moderate-risk individuals and a significant 177% estimated increase (95% CI, 66%-361%) among those at high risk. In unknown/low-risk individuals, there was a significant 52% (95% CI, 46%-58%) estimated fall in antibiotic prophylaxis prescribing, but no significant increase in IE incidence.


The authors concluded that antibiotic prophylaxis prescribing fell among all IE risk groups, particularly those at moderate risk.


This study reports that following publication of the 2007 AHA recommendations, there was a significant reduction in antibiotic prophylaxis prescribing. Furthermore, consistent with the new recommendations, the greatest reduction was among those at moderate risk of IE. However, synchronously there was a significant increase in IE incidence among high-risk individuals, a borderline significant increase in moderate-risk individuals, and no change for those at low/unknown risk. Additional studies are indicated to evaluate whether the observed association is causal and if recommendations for antibiotic prophylaxis need revision to prevent endocarditis while curtailing the adverse consequences of overprescribing antibiotics.

Clinical Topics: Prevention

Keywords: AHA Annual Scientific Sessions, AHA18, Anti-Bacterial Agents, Antibiotic Prophylaxis, Drug Prescriptions, Endocarditis, Endocarditis, Bacterial, Medicaid, Primary Prevention, Risk Factors, Vascular Diseases

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