Association of Medicaid Expansion With 5-Year Changes in Hypertension and Diabetes Outcomes at Federally Qualified Health Centers.

Importance: State decisions to expand Medicaid eligibility were particularly consequential for federally qualified health centers (FQHCs), which serve 30 million low-income patients across the US. The longer-term association of Medicaid expansion with health outcomes at FQHCs is unknown. Objective: To assess the 5-year association of Medicaid expansion with uninsurance rates and hypertension and diabetes outcome measures by race and ethnicity in a nationally representative population of FQHCs. Design Setting and Participants: Using a difference-in-differences analysis of a retrospective cohort from the universe of US FQHCs, changes in uninsurance rates and intermediate health outcomes for hypertension and diabetes by race and ethnicity were compared between Medicaid expansion and nonexpansion states before (2012-2013) vs after (2014-2018) expansion. Data were analyzed from September 2020 to March 2021. Exposures: Location in a state that expanded Medicaid eligibility as of 2014. Main Outcomes and Measures: Rates of uninsurance, the proportion of patients with hypertension with a blood pressure less than 140/90 mm Hg, and the proportion of patients with diabetes with glycosylated hemoglobin levels of 9% or less, as stratified by race and ethnicity. Results: Of the patients at 578 expansion-state FQHCs (serving 13.0 million patients per year) and 368 nonexpansion-state FQHCs (serving 6.0 million patients per year) in our study sample, 64.4% were age 18 to 64 years, 57.4% were women, 18.9% were non-Hispanic Black, and 27.3% were Hispanic. Following expansion, FQHCs in Medicaid expansion states experienced a 9.24 percentage point (PP) (95% CI, 7.94-10.54) decline in rates of uninsurance over the pooled 5-year expansion period compared with nonexpansion-state FQHCs. Across this 5-year period, expansion was associated with a 1.61-PP (95% CI, 0.58-2.64) comparative improvement in hypertension control and a 1.84-PP (95% CI, 0.71-2.98) comparative improvement in glucose control. Stratified results suggest that improvements were consistently observed in Black and Hispanic populations. The magnitude of change tended to increase with implementation time. For instance, by year 5, expansion was associated with a 3.38-PP (95% CI, 0.80-5.96) comparative improvement in hypertension control and a 3.88-PP (95% CI, 0.86-6.90) comparative improvement in glucose control among Black populations. Conclusions and Relevance: In this nationally representative cohort study, Medicaid expansion was associated with sustained increases in insurance coverage and improvements in chronic disease outcome measures at FQHCs after 5 years overall and among Black and Hispanic populations. States considering Medicaid expansion may benefit from improved longer-run health measures for underserved patients with chronic conditions.