European Primary Care Cardiovascular Society

More infectious endocarditis since antibiotics no longer recommended at dental procedures

News - Nov. 20, 2014

The Incidence of Infective Endocarditis in England is Increasing - An Assessment of the Impact of Cessation of Antibiotic Prophylaxis Using Population Statistics  

Presented at the AHA Scientific Sessions 2014 by: Martin Thornhill University of Sheffield School of Clinical Dentistry, Sheffield, UK
LBCT.03 - Treatment of Structural Heart Disease


Infectious endocarditis (IE), an infection of the myocardium, is associated with a high death rate (11% in-hospital). It is generally caused by viridans streptococci and Staphylococcus aureus. A prolong duration of intravenous antibiotics and hospital stay is needed, as well as cardiac surgery.
It is assumed that invasive dental procedures can lead to release of viridans streptococci into the blood stream, through which IE can develop in susceptible individuals. Giving antibiotic prophylaxis (AP) may reduce this risk.
In the past 60 years a tendency can be seen towards shorter duration and lower dose of antibiotics, and that fewer patients are considered to be at risk of IE. There has never been a randomised study into the use of AP in this context.
In March 2008, the National Institute for Health and Care Excellence (NICE) in the United Kingdom recommended that patients no longer need antibiotics for the prevention of IE in the case of invasive dental procedures and certain non-dental procedures. The situation in the United Kingdom provides a natural experiment to examine the impact on a national level of stopping to give AP. All patients with ICD-10 codes at discharge were included. All prescriptions are registered by the NHS Business Service Authority.

Main results

  • The number of IE cases per month increased significantly after publication of the NICE guidelines in March 2008, as compared to the earlier trend (0.62 cases/month, 95%CI: 0.35-0.89, P<0.001).
  • In March 2013 this amounted to 35 extra IE cases per month, or 420 IE cases per year.
  • A possible, but not significant increase of 1.5 IE mortality case per month, or 18 IE mortality cases per year were observed after March 2008.
  • The increase in IE cases was seen in both low- and high-risk patients.


Five year after the introduction of a NICE guideline with respect to antibiotic prophylaxis at dental procedures, a strong decrease in the prescription of AP was seen, and a significant increase of the incidence of infectious endocarditis, in both the highest and the lowest risk categories. Although it is only a temporal association, it cannot be concluded that this is a causal relationship. Other possible explanations for the increased IE incidence were explored, but could not give alternative explanations for the observations. A prospective randomised controlled study would better answer this question.

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