Endocarditis continues to cause considerable morbidity and mortality among older Americans, according to a study published Dec. 10 in the Journal of the American College of Cardiology. Although guidelines called for a reduction in the use of antibiotic prophylaxis for endocarditis, the rates of hospitalization and mortality have not increased, but remain high.

“Little is known about more recent national trends in endocarditis hospitalizations and outcomes among older adults, a growing population who may be at disproportionately high risk of developing and dying from endocarditis,” wrote the authors, led by Behnood Bikdeli, MD, of Yale-New Haven Hospital in New Haven, Conn.

They analyzed Medicare data for adults 65 and older diagnosed with endocarditis between 1999 and 2010 to determine hospitalizations and mortality rates at 30 days and one year. They compared their rates to those prior to 2007, the year the American Heart Association (AHA) issued its guidelines.

There were 262,658 beneficiaries hospitalized with endocarditis. The hospitalization rate between 1999 and 2005 was 83.5 per 100,000 person-years, higher than during 2006 and 2007 as well as after 2007 (70.6 per 100,000 person-years in 2010). Between 1999 and 2010, 30-day mortality ranged from 14.2 percent and 16.5 percent. One-year mortality ranged from 32.6 percent to 36.2 percent.

“Our study demonstrated the high burden of endocarditis among the older adult fee-for-service Medicare beneficiaries,” the authors wrote.

Hospitalization and mortality did not increase despite the AHA guidelines. The authors explained this finding could mean that there may not be safety issues associated with the restricted prophylaxis, that clinicians are not implementing the guidelines or that hospitalizations may have changed in a way unrelated to the change in antibiotic use.