Acute Myocardial Infarction in the Medicare Population

OBJECTIVE: To describe the process of care and clinical outcomes associated with acute myocardial infarction (AMI) in the Medicare population, and to examine differences in process of care and outcome of care as a function of patient age, gender, and race. DESIGN: Retrospective cohort study using a longitudinal database created from Medicare utilization and administrative files. PATIENT POPULATIONS: A cohort of AMI patients covered by Medicare in 1987 and a random sample of Medicare patients without AMI. MAIN PROCESS AND OUTCOME MEASUREMENTS: (1) The use of coronary angiography, coronary artery bypass graft surgery, and percutaneous transluminal coronary angioplasty during the first 90 days after a new AMI; (2) mortality at 30 days, 1 year, and 2 years; (3) reinfarction rates; and (4) reoperation rates for coronary artery bypass graft surgery and percutaneous transluminal coronary angioplasty. MAIN RESULTS: Mortality rates were high: 26% at 30 days, 40% at 1 year, and 47% at 2 years. They varied greatly by age, less so by gender and race, and were high even among patients who survived the first 30 days. Compared with mortality, reinfarction was uncommon, occurring in 7.3% of patients. During the first 90 days, 23% of all patients underwent angiography and 13% underwent coronary revascularization (coronary artery bypass graft surgery, 8%; percutaneous transluminal coronary angioplasty, 5%). The use of all three procedures decreased with age and was less common among women and blacks than among men and whites. Differential use by age and race was greater for angiography than for revascularization procedures. CONCLUSIONS: The prognosis following AMI in patients aged 65 years and above is much worse than is commonly realized. Procedure use in these patients varies as a function of gender and race, even though mortality does not. Further research is needed to reduce the mortality of elderly patients with AMI and to understand the significance of differences in procedure use on the basis of sociodemographic characteristics.