Abstract 9569: Incidence of Acute Coronary Syndrome in the General Medicare Population, 1992-2009: A Real-World Perspective

Abstract

Introduction: Acute coronary syndrome (ACS) is a major cause of mortality and morbidity among elderly patients in the US. We examined temporal trends in the incidence of ACS in Medicare patients over nearly two decades employing administrative data. Methods: The 5% Medicare database (~ 1.8 million pts/cohort yr) was used to identify ACS pts (age 65+, no ESRD) between 1992-2009. Medicare claims were used to identify patients hospitalized with ACS using the following ICD-9-CM diagnostic codes: acute myocardial infarction (AMI, 410) and unstable angina (UA, 411). Results: The incidence of ACS in the elderly Medicare population remained 2.4-2.5% between 1999-2002 and subsequently decreased to 1.7% by 2009 ("A" in the Figure). The trend was similar for all age, gender and race groups ("B" in the Figure) with the exception of patients > 84 years, for whom the incidence of ACS increased from 2.8% in 1992 to 3.4% in 2002, before declining to 2.6% in 2009. The decrease in incidence of ACS since 2001 was driven by a decrease in diagnosis of UA (1.6-1.7% in 1992-1997 to 0.6% in 2009) but not in the diagnosis of AMI (holding steady between 1.2-1.4%), perhaps reflecting the introduction of more sensitive cardiac biomarkers. Conclusion: Improved cardiovascular outcomes in the US have also impacted elderly patients with ACS. In the last decade, there has been a steady progressive decline in the incidence of ACS in Medicare patients.