Antibiotic Prophylaxis Recommended for Patients at High Risk of Infective Endocarditis

Dentistry Today


Research at the University of Sheffield has revealed the impact that a change in United States guidelines has had on the prescribing of antibiotic prophylaxis (AP) to prevent a life-threatening heart condition known as infective endocarditis (IE) in patients before invasive dental treatment.

The researchers also say that their findings provide further evidence that the United Kingdom’s National Institute of Health and Care Excellence (NICE) was wrong to call for a complete ban on the use of AP before invasive dental procedures, even for those considered at high risk of IE such as patients with artificial or repaired heart valves or a previous history of IE.

The study is the largest and most comprehensive research into the 2007 American Heart Association (AHA) recommendations that AP should continue to be given to patients at high risk of developing IE but not to those at moderate risk.

The research showed a large fall in AP prescriptions for those at moderate risk of IE (64%). But it also identified a concerning fall in AP prescriptions for those at high risk (20%) despite the AHA recommendation that high-risk individuals should continue to receive AP before invasive dental treatment. In parallel, the study also identified a 177% increase in IE in those at high risk but only a barely significant increase in those at moderate risk.

“Although the data do not prove a cause-effect relationship between AP reduction and IE increase, they are very supportive of the AHA recommendation to give AP to those at high risk but not to those at moderate risk of endocarditis,” said lead author Martin Thornhill, MBBS, BDS, PhD, MSc, of the University of Sheffield School of Clinical Dentistry.

“It also provides further evidence that the 2008 NICE recommendation that AP should cease completely in the UK was probably wrong and should be changed. Current NICE guidance on the use of AP to prevent IE is confusing and unhelpful for clinicians and patients and probably wrong,” said Thornhill.

“In the absence of clear and sensible advice from NICE, the recent attempt by the Scottish Dental Clinical Effectiveness Program (SDCEP) to provide advice for dentists about how to implement the NICE guidelines, effectively suggesting they follow the AHA recommendations, is very welcome,” said Thornhill.

IE is a serious infection of the heart valves with high morbidity and mortality, with 30% of patients dying within a year of diagnosis. Previous studies have shown that about 40% of cases are likely to have been caused by oral bacteria.

Many people with predisposing cardiac conditions are at increased risk of IE. Some patients such as those with prosthetic or repaired heart valves, previous history of IE, or certain congenital heart conditions are at high risk of developing IE.

“The recent implementation advice by SDCEP is a timely recognition that the patient has the right to be told the arguments both for and against prophylaxis and decide whether or not they wish to take it,” said consultant cardiologist and study coauthor Mark Dayer, PhD, of Taunton and Somerset National Health Service Trust.

“To my mind, the data in this study further supports the use of prophylaxis in patients at high risk of endocarditis as recommended in America and across the rest of Europe,” said Dayer. 

Since the 1950s, the main method for preventing IE worldwide has been to give those at increased risk AP before invasive dental and medical procedures. But a lack of evidence for the efficacy of AP, concerns about the risk of adverse reactions, and the development of antibiotic resistance has led guideline committees to gradually reduce the number of situations where AP is recommended. 

In 2018, however, NICE recommended the complete cessation of AP in the UK despite a lack of evidence for or against AP efficacy, the researchers said. In contrast, most guidelines committees around the world including the AHA recommended that individuals at high risk of IE should continue to receive AP but it should stop for those at moderate risk. 

In 2015, Thornhill and his colleagues found that the 2008 change in NICE guidelines led to an 89% fall in AP prescriptions in the UK. They also found an increase of 35 IE cases per month since the guideline chance. As a result, NICE reviewed its guidance but continued to recommend against AP.

The researchers say the new study provides further evidence to support the advice from the AHA and most other guideline committees around the world that those at high risk of IE undergoing invasive dental procedures should receive AP. It also supports the recently published SDCEP advice about how to implement the NICE guidelines, which tell dentists to discuss and offer AP to patients at high risk of IE, just like the AHA guidelines. 

The study, “Antibiotic Prophylaxis and Incidence of Endocarditis Before and After the 2007 AHA Recommendations,” was published by the Journal of the American College of Cardiology.

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