Objective: Little U.S. pharmacoepidemiologic study is based on treatment during continuous enrollment for periods more than a year. This study aims to show pediatric patterns of stimulant use (alone or with other psychotropic classes) from Medicaid administrative claims data for stimulant patterns of 3- to 8-year continuous enrollees. Methods: A retrospective cohort study was derived from Medicaid enrollment, pharmacy, and diagnosis claims data (2007-2014) in a mid-Atlantic state. Youth aged 2-17 years with 3-8 years of continuous enrollment treated with stimulants were compared with a date-matched comparison group treated without stimulants. Major outcomes include prevalence and duration of stimulant use and patterns of stimulant polypharmacy across relatively long enrollments (3-8 years). Results: Among 264,518 unique 2- to 17-year olds with 3-8 years of continuous enrollment, 16.5% had stimulant prescription dispensings, doubling the annual national prevalence of 8.1%. Subgroup analysis showed that the highest prevalence of stimulant use was for 6- to 11-year olds (20.4%), foster care eligible youth (42.3%), and those with 7-8 years of continuous enrollment (20.1%). Externalizing psychiatric disorders were far more common in those treated with stimulants than in those treated without stimulants. The duration of stimulant exposure overall was a median of 487 days, half that of foster care stimulant users. Stimulant polypharmacy with two or more psychotropic classes concomitantly characterized 29.8% of stimulant users. Among those with three or four or more class polypharmacy, 85% and 88%, respectively, had concomitant stimulant and antipsychotic use. The adjusted odds ratio (AOR) of three or more class polypharmacy significantly increased in 12- to 17-year-old age group (AOR = 1.8), foster care eligibility (AOR = 4.5), and among those with the longest enrollment (AOR = 1.7). Conclusions and Relevance: Stimulant prevalence in Medicaid-insured youth with continuous enrollment of 3-8 years was twice as common as in annual data sets. Future research should investigate three to five interclass stimulant polypharmacy effectiveness in reliably diagnosed community populations.
Keywords: Medicaid; children and adolescents; long-term use; polypharmacy.