What is the incidence of viridans group streptococci infective endocarditis (VGS-IE) following guideline changes in the US and UK?

Updated: Feb 05, 2018
  • Author: Mary L Windle, PharmD; Chief Editor: Karlheinz Peter, MD, PhD  more...
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Several studies have tracked the incidence of viridans group streptococci infective endocarditis (VGS-IE) following the guideline changes in the United States and the United Kingdom instituted in 2007 and 2008 respectively.

In the United States, Desimone et al found no perceivable increase in the incidence of VGS-IE in a localized area of Minnesota since the publication of the 2007 AHA endocarditis prevention guidelines. Rates of incidence (per 100,000 person-years) during the intervals of 1999-2002, 2003-2006, 2007-2010, and 2011-2013 were 3.6, 2.7, 0.7, and 1.5, respectively, reflecting an overall significant decrease (P=.03 from Poisson regression). Likewise, nationwide estimates of hospital discharges with a VGS-IE diagnosis trended downward during 2000-2011, with a mean number per year of 15,853 and 16,157 for 2000-2003 and 2004-2007, respectively, decreasing to 14,231 in 2008-2011 (P=.05 from linear regression using weighted least squares method). [5, 6]

A large retrospective epidemiologic study of patients hospitalized with a first episode of IE was conducted to quantify trends in the incidence and etiologies of infective endocarditis in the United States was conducted in California and New York. IE cases from mandatory state databases between January 1, 1998 and December 31, 2013 were analyzed. Among 75,829 patients with first episodes of endocarditis, the standardized annual incidence was stable between 7.6 (95% CI, 7.4 to 7.9) and 7.8 (95% CI, 7.6 to 8.0) cases per 100 000 persons. [7]

Mitral valve prolapse affects approximately 2-3% of the general population. The first report of population-based incidence of IE in 896 patients with contemporary echocardiographic diagnosis of mitral valve prolapse (MVP) was analyzed based on the largest geographically-defined MVP community-cohort with longest follow-up available for this purpose. The study reports the incidence of IE in patients with echocardiographic MVP diagnosis to be approximately 87 cases per 100,000 person-years, which represents approximately 8 times the risk of IE in the general population. Prior studies reported wide variation in the estimated incremental relative risk of IE in MVP patients compared to nonMVP patients (2.9-8.2). [8]

The findings of one study supported the 2008 National Institute for Health and Clinical Excellence (NICE) in the United Kingdom guideline recommendations that antibiotic prophylaxis prior to invasive dental procedures was likely to not be of benefit in preventing infective endocarditis in patients with a history of rheumatic fever or a heart murmur. The authors did suggest though that patients at highest risk (eg, those with prosthetic valves) still might benefit. [9] Note that the study was conducted in England; therefore, a limitation of the study is the external generalizability of the findings to other countries.

Dayer et al investigated changes in the prescribing of antibiotic prophylaxis and the incidence of infective endocarditis in England since the introduction of the 2008 NICE guidelines. Although the data from the study did not establish a causal association, prescriptions of antibiotic prophylaxis have fallen substantially and the incidence of infective endocarditis has increased significantly in England since introduction of the 2008 NICE guidelines. [10] Thornhill et al also reported that since March 2008 there has been an increase in IE cases since the 2008 NICE guidelines. [11] The NICE Clinical Guidelines were updated in 2015 to address this research that reported an increase in IE cases, however, NICE did not change their recommendations and no longer recommended antibiotic prophylaxis in patients at high-risk of IE who are undergoing high-risk dental procedures. [12, 13] In 2015, The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC) released their guidelines that continued to recommend antibiotic prophylaxis only for patients at the highest risk. [14]

A study by Thornhill et al that reviewed five years of English hospital admissions for conditions associated with increased infective endocarditis risk reported that the patients at highest risk of recurrence or death during an infective endocarditis admission were patients with a previous history of infective endocarditis. Risks were also high in patients with prosthetic valves and previous valve repair. Patients at moderate risk included patients with congenital valve anomalies. Congenital heart conditions repaired with prosthetic material were at lower risk and risk was also seen in patients with cardiovascular implantable electronic devices. [15]

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