Medicaid ACO Implementation and Pediatric Asthma Care Equity.

OBJECTIVES: Poorly controlled asthma disproportionately impacts children from lower-income and racially or ethnically minority groups. We examined whether Massachusetts Medicaid Accountable Care Organization (ACO) implementation was associated with improved pediatric asthma care and outcomes and whether associations varied by race and ethnicity. METHODS: Using a difference-in-differences approach, we compared pre-implementation (2016-2017) to post-implementation (2018-2021) outcomes for Medicaid-insured children assigned to ACOs to those not assigned to ACOs. We examined differences overall and by race and ethnicity, using regression models accounting for differences in child demographics, health status, year, and ZIP code characteristics. RESULTS: Among 282 334 child-year observations (117 757 children), 80.7% were attributed to ACOs. Racial and ethnic categories included non-Hispanic White (37.9%), Hispanic (36.2%), and non-Hispanic Black (18.0%). ACO implementation was associated with a 3.0 percentage point (pp) increase in the probability of a routine asthma visit (95% CI: 2.1-3.8 pp), a decrease in an asthma medication ratio greater than 0.5 of 2.7 pp (95% CI: -5.3 to -0.2 pp), and a 2.1-pp decrease in the probability of any acute care (95% CI: -3.0 to -1.3 pp) for those in Medicaid ACOs vs other Medicaid-insured children. We found no consistent evidence that ACO implementation reduced racial and ethnic disparities in asthma care or outcomes. CONCLUSIONS: Implementation of Massachusetts Medicaid ACOs was associated with modest improvements in asthma care for routine asthma visits and acute care use but declines in appropriate medication use. Importantly, ACOs did not consistently reduce existing racial and ethnic disparities. Additional changes in the design of value-based care models in Medicaid are needed to address racial and ethnic disparities.