The effect of Massachusetts health reform on access to care for Medicaid beneficiaries.

OBJECTIVES: To address concerns that expanding insurance coverage without expanding provider supply can lead to worse access for the previously insured, we examined whether previously insured Medicaid beneficiaries faced greater difficulties accessing primary care after statewide insurance expansion in Massachusetts.

STUDY DESIGN: We used the Medicaid Analytic eXtract databases for Massachusetts and 3 New England control states for 2006 and 2009. We calculated rates of overall, acute, and chronic preventable admissions (or Prevention Quality Indicators [PQIs]) and a composite of control conditions for adults aged 21 to 64 years.

METHODS: We used multivariate Poisson regression models, adjusting for age, race, gender, reason for Medicaid eligibility, and state-level physician supply, as well as a difference-in-differences (DID) approach to compare the change in the rate of PQIs and control admissions in Massachusetts versus control states before and after health reform.

RESULTS: Massachusetts and control states had increases in unadjusted rates of overall, acute, and chronic PQIs. When adjusting for age, race, gender, reason for eligibility, and physician supply, this increase persisted for overall and chronic PQIs in control states, with no significant difference in the relative increase between the 2 groups for any of the PQI measures. For the within-Massachusetts analysis, low-uptake counties had a significant increase in admission for chronic PQIs that was greater than that observed for high-uptake counties (+148.0 vs +36.0; P = .045 for DID). There was no significant DID for acute or overall PQIs between the 2 groups.

CONCLUSIONS: We found no evidence that insurance expansion in Massachusetts, compared with control states, reduced access to primary care for vulnerable Medicaid beneficiaries.