Importance: Heart failure (HF) incidence is declining among Medicare beneficiaries. However, the epidemiological mechanisms underlying this decline are not well understood.
Objective: To evaluate trends in HF incidence across risk factor strata.
Design, setting, and participants: Retrospective, national cohort study of 5% of all fee-for-service Medicare beneficiaries with no prior HF followed up from 2011 to 2016. The study examined annual trends in HF incidence among groups with and without primary HF risk factors (hypertension, diabetes, and obesity) and predisposing cardiovascular conditions (acute myocardial infarction [MI] and atrial fibrillation [AF]).
Exposures: The presence of comorbid HF risk factors including hypertension, diabetes, obesity, acute MI, and AF identified by International Classification of Diseases, Ninth Revision, Clinical Modification codes and International Statistical Classification of Diseases, Tenth Revision, Clinical Modification codes.
Main outcomes and measures: Incident HF, defined using at least 1 inpatient HF claim or at least 2 outpatient HF claims among those without a previous diagnosis of HF.
Results: Of 1 799 027 unique Medicare beneficiaries at risk for HF (median age, 73 years [interquartile range, 68-79 years]; 56% female [805 060-796 253 participants during the study period]), 249 832 had a new diagnosis of HF. The prevalence of all 5 risk factors increased over time (0.8% mean increase in hypertension per year, 1.9% increase in diabetes, 2.9% increase in obesity, 0.2% increase in acute MI, and 0.4% increase in AF). Heart failure incidence declined from 35.7 cases per 1000 beneficiaries in 2011 to 26.5 cases per 1000 beneficiaries in 2016, consistent across subgroups based on sex and race/ethnicity. A greater decline in HF incidence was observed among patients with prevalent hypertension (relative excess decline, 12%), diabetes (relative excess decline, 3%), and obesity (relative excess decline, 16%) compared with those without corresponding risk factors. In contrast, there was a relative increase in HF incidence among individuals with acute MI (26% vs no acute MI) and AF (22% vs no AF).
Conclusions and relevance: Findings of this study suggest that the temporal decline in HF incidence among Medicare beneficiaries reflects a decrease in HF incidence among those with primary HF risk factors. The increase in HF incidence among those with acute MI and those with AF highlights potential targets for future HF prevention strategies.