Incidence of Infective Endocarditis in England, 2000–13: A Secular Trend, Interrupted Time-Series Analysis

Study Questions:

Did the 2008 change in recommendations for infective endocarditis (IE) prophylaxis in the United Kingdom result in a change in IE incidence?


A retrospective secular trend study was performed and analyzed as an interrupted time series to investigate the effect of antibiotic prophylaxis versus no prophylaxis on the incidence of IE in England. Data for the prescription of antibiotic prophylaxis were analyzed from January 1, 2004 to March 31, 2013, and for hospital discharge statistics for patients with a primary diagnosis of IE from January 1, 2000 to March 31, 2013. The incidence of IE before and after the introduction of the March 2008 National Institute for Health and Clinical Excellence (NICE) guidelines was compared using segmented regression analysis of the interrupted time series.


Prescriptions of antibiotic prophylaxis for the prevention of IE fell substantially after introduction of the NICE guidelines (mean 10,900 prescriptions per month [January 1, 2004 to March 31, 2008] vs. 2,236 prescriptions per month [April 1, 2008 to March 31, 2013], p < 0.0001). Starting in March 2008, the number of cases of IE increased significantly above the projected historical trend, by 0.11 cases per 10 million people per month (95% confidence interval, 0.05–0.16; p < 0.0001). By March 2013, 35 more cases per month were reported than would have been expected had the previous trend continued. This increase in the incidence of IE was significant for both individuals at high risk of IE and for those at lower risk.


Although these data do not establish a causal association, prescriptions of antibiotic prophylaxis have fallen substantially and the incidence of IE has increased significantly in England since introduction of the 2008 NICE guidelines.


Antibiotic prophylaxis given before dental procedures in patients at risk of developing IE historically has been a focus of IE prevention. In the absence of prospective randomized trials, guideline recommendations changed in 2008 both in the United States (American College of Cardiology/American Heart Association) and the United Kingdom (NICE), such that prophylaxis no longer is recommended for most patients with native heart valve disease. Data from this study suggest that the experiment might be failing, and that adherence to the revised guidelines is at least temporarily associated with an increase in the incidence of IE. This clinician still believes that the choice of an informed patient should supersede evidence-less guideline recommendations (Bach DS. J Am Coll Cardiol 2009;53:1852-4; and Bach DS. Methodist DeBakey Cardiovasc J 2010;6:48-52).

Keywords: Dental Care, American Heart Association, Antibiotic Prophylaxis, Endocarditis, Bacterial, Regression Analysis, England, AHA Annual Scientific Sessions

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