Recommendations restricting the use of antibiotic prophylaxis before invasive dental procedures to only a handful of patient groups did not appear to increase rates of infective endocarditis caused by viridans group streptococci, researchers found.
Among 22 patients diagnosed with the infection over a 12-year period in Olmsted County, Minn., only three received the diagnosis after the restrictions were issued, according to Daniel DeSimone, MD, of the Mayo Clinic in Rochester, Minn., and colleagues.
Action Points
- Explain that the incidence of strep viridans endocarditis did not increase in the 3 years following the American Heart Association's revised guidance recommending decreasing the number of patients receiving antibiotic prophylaxis prior to routine procedures.
- Note that it was a small study in a white population with few cases of strep viridans endocarditis and that compliance with the revised guidelines could not be ascertained.
And the rate was actually lower after the updated guidance was published than it was just prior to publication, although the declining trend did not reach statistical significance (0.77 versus 3.19 per 100,000 person-years, P=0.061 for trend), the researchers reported online in Circulation: Journal of the American Heart Association.
"Nevertheless, limitations of the study, including a small annual number of infective endocarditis cases, mandate continued evaluation of incidence trends over an extended period of time, both locally and elsewhere, before concerns regarding increasing incidence of viridans group streptococci infective endocarditis related to changes in guidelines recommendations can be addressed fully," the authors wrote.
The American Heart Association first issued formal guidelines for the use of infective endocarditis prophylaxis in patients with specific cardiovascular conditions undergoing certain dental procedures in 1955.
In 2007, the organization updated the guidance to restrict the use of antibiotic prophylaxis to a small number of at-risk patients, including those with underlying cardiac conditions conferring the highest risk of a poor outcome from infective endocarditis. Prophylaxis was no longer recommended for invasive gastrointestinal or genitourinary procedures.
To see whether the new guidance was associated with an increase in infective endocarditis caused by viridans group streptococci, which has been linked to invasive dental procedures, the researchers examined data on all definite or probable cases identified in the Rochester Epidemiology Project of Olmsted County from 1999 through 2010.
Only 22 cases were identified, resulting in sex-adjusted rates of 3.19, 2.48, and 0.77 per 100,000 person-years for the first 4 years, second 4 years, and final 4 years of the study period, respectively.
Of the three cases identified after the revised guidance was released in 2007, two had not undergone any dental procedures within 6 months of admission. The third patient had a dental procedure 2 weeks before symptom onset and had taken clindamycin 30 minutes before the procedure.
Only two of the 22 total cases were considered healthcare-associated, and the rest were classified as community-acquired.
To look at broader trends, the researchers also examined data from the Nationwide Inpatient Sample for 1999 through 2009. The number of hospital discharges for infective endocarditis caused by viridans group streptococci remained relatively stable during the study period.
The researchers acknowledged that the study was limited by the small sample size, the relatively short amount of time between the guideline revision and the end of follow-up, the mostly white study population, and the limited data on compliance with the new recommendations.
Disclosures
The study was supported by research grants from the Baddour Family Fund, Mayo Foundation for Medical Education and Research.
DeSimone reported that he had no conflicts of interest. His co-authors reported relationships with TyRx, UpToDate, the Massachusetts Medical Society (Journal Watch Infectious Diseases), and the American College of Physicians (PIER [Physicians' Information and Education Resource]).
Primary Source
Circulation: Journal of the American Heart Association
DeSimone D, et al "Incidence of infective endocarditis caused by viridans group streptococci before and after publication of the 2007 American Heart Association's endocarditis prevention guidelines" Circulation 2012; DOI: 10.1161/CIRCULATIONAHA.112.095281.