Burden of Coronary Heart Disease Rehospitalizations Following Acute Myocardial Infarction in Older Adults.

PURPOSE: Studies of prognosis following acute myocardial infarction (AMI) conventionally examine the first recurrent coronary heart disease (CHD) event which may not adequately characterize the full burden of CHD hospitalizations. We therefore examined the cumulative number of CHD rehospitalizations following AMI among older adults in the United States. METHODS: We conducted a retrospective cohort study of 78,085 Medicare beneficiaries aged ≥66 years without recent CHD history who were hospitalized for AMI in 2000-2010. Counts of CHD rehospitalizations over a maximum of 10 years of follow-up were calculated. Characteristics were assessed through claims and enrollment information and associations with CHD rehospitalizations were evaluated using Poisson models. RESULTS: Over 25 % of beneficiaries were aged ≥85 years, 55 % were women, and 89 % were white. Comorbidities were common, including diabetes (22.9 %), hypertension (46.7 %), heart failure (10.3 %), and chronic obstructive pulmonary disease (19.2 %). Following AMI, 16,078 beneficiaries (20.6 %) were hospitalized for CHD a total of 23,132 times. Among those who experienced at least one CHD rehospitalization, 35.9 % had ≥2 CHD rehospitalizations (n = 5773, 7.4 % of all beneficiaries with AMI) in the ensuing decade. Associations of demographics, comorbidities, and index hospitalization characteristics with rates of first and total CHD rehospitalizations were largely similar. Age ≥85 years versus 66-69 years was more strongly associated with first (rate ratio [RR] 1.43) than total (RR 1.35) CHD rehospitalization (p < 0.05), as was male versus female sex (RR 1.13 and 1.07). CONCLUSIONS: Emphasizing the first recurrent CHD rehospitalization underestimates the burden of disease experienced among older adults with AMI.