High-need beneficiary enrollment patterns in Medicare Advantage and traditional Medicare.

Objectives: High-need Medicare beneficiaries require elevated levels of care and coordination to manage their conditions. We evaluated the extent to which high-need beneficiaries enrolled in Medicare Advantage (MA) or traditional Medicare (TM) accountable care organizations (ACOs) relative to TM non-ACOs.
Study Design: Using Medicare claims and MA encounter data, we identified 3 groups of high-need beneficiaries: (1) individuals younger than 65 years with a disability or end-stage kidney disease, (2) frail individuals, and (3) older individuals with major complex or multiple noncomplex chronic conditions. For comparison, we included non-high-need beneficiaries in the analysis, including those with minor complex chronic conditions.
Methods: Descriptive analysis of Medicare enrollment patterns and beneficiary characteristics of high-need and other beneficiaries between 2016 and 2019.
Results: In 2019, high-need beneficiaries accounted for 18 million or 32% of enrollees in TM and MA, an increase of approximately 1 million since 2016, driven by growth in MA. A larger share of beneficiaries in TM ACOs was high need (38%) compared with MA (24%). Although the total count of high-need beneficiaries in TM remained stable from 2016 to 2019, ACOs saw an increase of almost 1.5 million high-need beneficiaries (39% increase), and TM non-ACOs saw a decrease of 1.9 million (23% decrease).
Conclusions: We found that high-need beneficiaries were more likely to be in TM non-ACOs than in MA through 2019. However, an increasing number of these beneficiaries are enrolling in MA or aligned with a TM ACO. A projected increase in the population of older adults will increase the economic burden of caring for high-need individuals.