Effects of Global Budget Payments on Vulnerable Medicare Subpopulations in Maryland.

There is little evidence regarding population equity in alternative payment models (APMs). We aimed to determine whether one such APM, the Maryland All-Payer Model (MDAPM), had differential effects on subpopulations of vulnerable Medicare beneficiaries. We utilized Medicare fee-for-service claims for beneficiaries living in Maryland and 48 comparison hospital market areas between 2011 and 2018. We used doubly robust difference-in-difference-in-differences regression models to estimate the differential effects of MDAPM on Medicare beneficiaries by dual eligibility for Medicare and Medicaid, disability as original reason for Medicare entitlement, presence of multiple chronic conditions (MCC), race, and rural residency status. Dual, disabled, and beneficiaries with MCC had greater reductions in expenditures and utilization than their counterparts. Hospitals may have prioritized high-cost, high-need patients as they changed their care delivery practices. The percentage of hospital discharges with 14-day follow-up was significantly lower for disadvantaged subpopulations, including duals, disabled, and non-White.