"Although enrollment of commercially insured individuals in health maintenance organizations (HMOs) has decreased in recent years, HMOs continue to provide care for an increasing proportion of the Medicaid population. Between 1994 and 2004, enrollment in Medicaid managed care tripled from 7.9 million beneficiaries to more than 27 million beneficiaries. The proportion of Medicaid beneficiaries in managed care increased from 23 percent to more than 60 percent during the same time period," the authors write. There is limited information in peer-reviewed literature on the quality of care delivered within health plans to Medicaid enrollees.
Bruce E. Landon, M.D., M.B.A., of Harvard Medical School, Boston, and colleagues examined performance on 11 Healthcare Effectiveness Data and Information Set (formerly the Healthplan Employer Data and Information Set) (HEDIS) quality indicators in three types of managed care plans: Medicaid-only plans, commercial-only plans (health plans serving predominantly commercial enrollees), and Medicaid/commercial plans (health plans serving substantial numbers of both types of enrollees). The 11 indicators were in the categories of prevention and screening (such as breast cancer screening); chronic disease management (such as high blood pressure); and care for pregnant women.
The study included 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; and 37 Medicaid-only plans.
When comparing the quality of care indicators for the Medicaid and commercial populations together, overall commercial population performance exceeded overall Medicaid population performance in all instances except one, ranging from a difference of 4.9 percent for controlling hypertension (58.4 percent for commercial vs. 53.5 percent for Medicaid) to 24.5 percent for rates of appropriate postpartum care (77.2 percent for commercial vs. 52.7 percent for Medicaid). The one exception was chlamydia screening, for which Medicaid performance exceeded commercial performance (41.8 percent vs. 25.3 percent). When comparing performance for Medicaid and commercial populations within the same health plan, performance for the commercial population was uniformly better across all measures.
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.
"These findings suggest that the type of health plan enrolling the population (commercial, Medicaid/commercial, or Medicaid-only) is a less important determinant of the quality of care than differences in the characteristics of the population being served, the local provider networks in which they receive care, access to care, patterns of care seeking, and adherence to treatment recommendations," the researchers write.