Context: In contrast to the commercially insured population, the proportion of Medicaid beneficiaries enrolling in health maintenance organizations continues to increase.
Objective: To compare quality of care within and between the Medicaid and commercial populations in 3 types of managed care plans: Medicaid-only plans (serving predominantly Medicaid enrollees), commercial-only plans (serving predominantly commercial enrollees), and Medicaid/commercial plans (serving substantial numbers of both types of enrollees).
Design, setting, and participants: All 383 health plans that reported quality-of-care data to the National Committee for Quality Assurance for 2002 and 2003, including 204 commercial-only plans, 142 Medicaid/commercial plans (plans reported data for the Medicaid and commercial populations separately); and 37 Medicaid-only plans.
Main outcome measures: Eleven quality indicators from the Healthcare Effectiveness Data and Information Set (HEDIS) applicable to the Medicaid population.
Results: Among Medicaid enrollees, performance on the 11 measures observed in this study were comparable for Medicaid-only plans and Medicaid/commercial plans. Similarly, among commercial enrollees, there was virtually no difference in performance between health plans that served only the commercial population and those that also served the Medicaid population. Overall across all health plan types, the performance for the commercial population exceeded the performance for the Medicaid population on all measures except 1, ranging from a difference of 4.9% for controlling hypertension (58.4% for commercial vs 53.5% for Medicaid; P = .002) to 24.5% for rates of appropriate postpartum care (77.2% for commercial vs 52.7% for Medicaid; P = .001). Differences of similar magnitude were observed for commercial and Medicaid populations treated within the same health plan.
Conclusions: Medicaid managed care enrollees receive lower-quality care than that received by commercial managed care enrollees. There were no differences in quality of care for the Medicaid population between Medicaid-only plans and commercial plans that also served the Medicaid population.