UC Berkeley

OBJECTIVE: The Centers for Medicare and Medicaid Services State Innovation Models (SIM) initiative has invested more than $1 billion to test state-led delivery system and payment reforms that can affect diabetes care management. We examined whether SIM implementation between 2013 and 2017 was associated with diagnosed diabetes prevalence or with hospitalization or 30-day readmission rate among diagnosed adults. RESEARCH DESIGN AND METHODS: The quasiexperimental design compared study outcomes before and after the SIM initiative in 12 SIM states versus five comparison states using difference-in-differences (DiD) regression models of 21,055,714 hospitalizations for adults age ≥18 years diagnosed with diabetes in 889 counties from 2010 to 2017 across the 17 states. For readmission analyses, comparative interrupted time series (CITS) models included 11,812,993 hospitalizations from a subset of nine states. RESULTS: Diagnosed diabetes prevalence changes were not significantly different between SIM states and comparison states. Hospitalization rates were inconsistent across models, with DiD estimates ranging from -5.34 to -0.37 and from -13.16 to 0.92, respectively. CITS results indicate that SIM states had greater increases in odds of 30-day readmission during SIM implementation compared with comparison states (round 1: adjusted odds ratio [AOR] 1.07; 95% CI 1.04, 1.11; P < 0.001; round 2: AOR 1.06; 95% CI 1.03, 1.10; P = 0.001). CONCLUSIONS: The SIM initiative was not sufficiently focused to have a population-level effect on diabetes detection or management. SIM states had greater increases in 30-day readmission for adults with diabetes than comparison states, highlighting potential unintended effects of engaging in the multipayer alignment efforts required of state-led delivery system and payment reforms.