Abstract 9795: Shifting Trends in Incidence and Mortality from Infective Endocarditis Among Medicare Beneficiaries

Abstract

Background: Infective endocarditis (IE) is the most serious cardiovascular infection in adults. The AHA guidelines in 2007 narrowed the indications for antibiotic prophylaxis for IE. Yet, little is known about recent IE trends among older adults (age≥65 years), who are a growing at-risk population in the United States.

Methods: We used the Inpatient Medicare standard analytic files to identify 100% of fee-for-service (FFS) patients aged ≥65 with a primary or secondary diagnosis of IE from 1999 to 2010. We built a denominator file from Medicare administrative data to report IE hospitalizations per 100,000 beneficiary-years. Thirty-day and 1-year mortality rates were determined using the vital status files from the Centers for Medicare & Medicaid Services.

Results: Annually, over 20,000 FFS Medicare beneficiaries were hospitalized with IE. IE incidence was 84 per 100,000 patient-years in 1999, rose gradually to 103 per 100,000 patient years in 2005, and has had a slight decline thereafter (Table 1). From 1999 to 2007, 30-day and 1-year mortality rates remained high, ~15% and ~ 35% respectively. Mortality rates during 2008 were at 16% and 37% respectively; however, risk-adjusted analysis did not show a consistent rise in mortality rates from 2008 onwards.

Conclusion: Although endocarditis is frequently cited as a rare condition with stable incidence, our findings signify the high burden of IE in older adults. We did not observe a major rise in IE hospitalizations or mortality rates after publication of AHA guidelines in 2007. Our observational study supports the safety of these recommendations.