Cardiovascular Hospitalizations for Medicare Advantage Beneficiaries in the United States, 2009 to 2019.

BACKGROUND: Federal programs measuring hospital quality of care for acute cardiovascular conditions are based solely on Medicare fee-for-service (FFS) beneficiaries, and exclude Medicare Advantage (MA) beneficiaries. Little is known about the proportion of Medicare beneficiaries enrolled in MA at the time of an acute cardiovascular hospitalization. Therefore, in this study we characterize the proportion of Medicare beneficiaries enrolled in MA at the time of acute myocardial infarction (AMI), heart failure (HF), and ischemic stroke hospitalization.

METHODS: Retrospective cross-sectional study of short-term acute care hospitals using Medicare claims in 2009 and 2019.

RESULTS: There were 2,653 hospitals in 2009 and 2,732 hospitals in 2019. Across hospitals, the proportion of Medicare beneficiaries hospitalized for AMI who were enrolled in MA increased between 2009 (hospital-level median 14.4% [IQR 5.1% to 26.0%]) and 2019 (33.3% [IQR 20.6% to 45.2%]), with substantial variation across hospitals. Similar patterns were observed for HF (13.0% [IQR 5.3% to 24.3%] to 31.0% [IQR 20.2% to 42.3%]) and ischemic stroke (14.6% [IQR 5.3% to 26.7%] to 33.3% [IQR 20.9% to 46.0%]). The proportion of hospitalized Medicare beneficiaries enrolled in MA was lowest in the New England region (hospital-level median 25.5%, IQR [17.5%-37.9%]) and highest in the Mid-Atlantic region (35.7%, IQR [26.6%-48.6%]). Within each hospital referral region, hospital size (large 36.3% vs small 24.5%; adjusted difference [AD] 6.7%, 95% CI, 4.5% to 8.8%), teaching status (teaching 34.5% vs non-teaching 28.2%; AD 2.8%, 1.4% to 4.1%), and ownership status (private non-profit 32.3% vs public 24.5%; AD 5.2%, 3.5% to 6.9%) were each associated with a higher hospital MA proportion. Rural (vs urban) location (18.4% vs 32.0%; AD -7.4%, -9.8% to -5.0%) was associated with lower hospital MA proportion.

CONCLUSIONS: The proportion of Medicare beneficiaries hospitalized for AMI, HF, and ischemic stroke enrolled in MA doubled between 2009 and 2019, with substantial variation across hospitals. These findings have implications for federal efforts to measure and improve quality, which currently focus only on FFS beneficiaries, as well as for the delivery of care to patients with acute cardiovascular conditions (e.g., prior authorizations, restricted provider networks).