Quality of drug treatment of childhood persistent asthma in Maryland Medicaid recipients in transition from managed fee for service to managed capitation

Background: From December 1991 to June 1997, approximately 80% of Maryland's Medicaid recipients were served through a fee-for-service (FFS) managed care delivery system in which assigned primary care providers served as gatekeepers for hospital and specialty services. The remaining 20% of recipients were voluntarily enrolled in 1 of 5 available health maintenance organizations (HMOs). Beginning in June 1997, Maryland required most Medicaid recipients to enroll in capitated managed care organizations (MCOs), also referred to as managed Medicaid plans. Although research has been conducted on the quality of asthma care among MCOs and in MCOs for Medicaid versus non-Medicaid members, the quality of asthma care has been less well studied for MCO patients than for FFS patients. Objective: To determine whether quality of drug use among Medicaid children with persistent asthma was different after the transition from the managed care FFS system to a capitated managed Medicaid system. Methods: This 4-year retrospective cohort study (from June 1, 1996, to December 31, 2000) followed children aged 5 to 18 years with persistent asthma (defined by the existence of at least 1 medical claim with an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code of 493.x and receipt of 2 or more pharmacy claims for beta₂-agonists in a 6-month period) enrolled in Maryland Medicaid as they transitioned from the managed FFS system to 1 of 4 large capitated MCOs. Children were selected from a review of Medicaid enrollment records and medical and pharmacy FFS claims filed between June 1, 1996, and December 31, 1997. Children with a diagnosis of cystic fibrosis were excluded. The asthma quality indicator was defined as the proportion of children with persistent asthma (who had 2 or more claims for any short-acting beta₂-agonists [SABAs], including metered-dose inhalers, nebulizers, or oral forms, which we defined as rescue medication, within a 6-month period), who also had at least 1 claim for a controller medication (inhaled corticosteroid, mast-cell stabilizer, or leukotriene-receptor modifier) in the same 6-month period. Subjects were followed from June 1, 1996 (or, if later, the first Medicaid eligibility date), through December 31, 2000 (or, if earlier, the last Medicaid eligibility date). Mean quality indicator rates were calculated for the 2 managed FFS periods (FFS1 and FFS2) and the 6 managed Medicaid 6-month periods. We used generalized estimating equations to test for significant trends over time and to compare changes in the quality indicator in the managed Medicaid plans. Results: There were 3,721 children who met the inclusion and exclusion criteria for the study. The quality indicator (proportion of patients who received a controller medication among those receiving SABAs for asthma) was 62% in managed FFS1 and 57% in managed FFS2. In the first 6 months of managed Medicaid plans, the quality indicator rose from 56% to 57%, 59%, 61%, 66%, and 59% in the ensuing five 6-month observation periods. The results from the generalized estimating equations suggested slight improvement in the quality indicator in the managed Medicaid plans, but the difference was not significant (relative risk 1.01,95% confidence interval, 0.95-1.08). There was no significant trend in the asthma quality indicator over time in the managed Medicaid plans. Conclusion: There was no distinct improvement or worsening in asthma care as measured by the quality indicator (proportion of patients who received a controller medication among those receiving SABAs for asthma) as children moved from managed FFS to managed Medicaid. Larger sample sizes with no data loss may have produced a different result.