Did Maryland All-Payer Global Budgets Change Hospital Margins and Revenue per Discharge? A Comparative Interrupted Panel Analysis, 2010–2023 (Maryland vs. Massachusetts)

Background: Maryland implemented an all-payer hospital global budget revenue (GBR) model in 2014 to decouple hospital revenue from volume and promote financial stability. Whether GBR altered hospital financial performance, particularly margins and inpatient revenue intensity, relative to comparable fee-for-service settings, remains contested. Methods: A matched hospital–year panel for Maryland and Massachusetts spanning 2010–2023 (2,261 matched observations) was constructed by merging Medicare cost report–based financial measures with provider characteristics using CMS certification identifiers. Two-way fixed-effects difference-in-differences models with hospital and year fixed effects and hospital-clustered standard errors estimated post-2014 changes in outcomes in Maryland relative to Massachusetts. Identification was assessed using a dynamic event-study specification and a placebo test (fake treatment in 2012, restricted to the pre-period). Financial stability under pandemic shock was evaluated using a COVID-period differential effect on margin volatility, defined as the absolute year-over-year change in total margin. Results: GBR implementation was not associated with a statistically detectable change in total margins (MD×post2014 β=0.021, p=0.232). In contrast, GBR was associated with higher inpatient revenue per discharge (log) in Maryland relative to Massachusetts after 2014 (MD×post2014 β=0.287, p=0.003), consistent with an approximate 33% increase in revenue per discharge (exp [0.287]−1). Margin volatility during COVID-19 did not differ significantly between states (MD×COVID β=−0.018, p=0.161). The placebo test showed no spurious “effect” in the pre-period (MD×placebo β=−0.008, p=0.801), supporting design validity. Conclusions: Maryland’s all-payer global budgets were associated with higher revenue per discharge but no detectable change in operating margins or differential margin volatility during COVID-19. These findings are consistent with GBR altering revenue intensity without clear evidence of improved profitability or shock-absorbing effects over 2010–2023.