Predictors Of Medication Nonadherence In Children/Adolescents With Attention Deficit Hyperactivity Disorder (Adhd) In Mississippi Medicaid Program

Objectives: To examine adherence to ADHD stimulant medications and determined the condition-related, therapy-related, patient-related, health-system related, and social and economic related predictors of medication nonadherence in children/adolescents (4 – 18 years) with ADHD enrolled in Mississippi Medicaid Program. Methods: This was a retrospective cohort study of the Mississippi Medicaid administrative claims data. Data was analyzed from March 01, 2014 to February 29, 2016. Adherence was calculated as the proportion of days covered (PDC). PDC was calculated including and excluding summer break (June – August) and at two different timelines, at 6 months and 12 months depending upon the length of continuous enrollment of patients. PDC less than 0.80 was considered nonadherent. Multivariable logistic regression model was constructed to identify predictors of medication nonadherence. Results: The study included 2,573 patients for PDC measure at 6 months, 58.88% were between 6 – 11 years of age, 68.71% of them were male, and 48.74% Caucasian. 2,428 patients for PDC measurement at 12 months were included. 59.23% were between 6 – 11 years of age, 68.29% of them were male, and 48.19% Caucasian. Including summer break, 67.24% of the patients were nonadherent at 6 months and 41.52% at 12-month measurement. Excluding summer break, 63.31% of the patients were nonadherent at 6 months and 43.45% at 12 months. To identify predictors of medication nonadherence, the cohort for adherence measurement at 6 months including summer break was used. In an unadjusted analysis, patients having non-severe ADHD, lack of follow-ups, using long-acting medications, having no psychiatric disorder, and between the age of 12 – 18 years were more likely to be nonadherent. Multivariable analysis revealed lack of follow-ups, having non-severe ADHD, African-American race, and geographical region – 5 as potential predictors of nonadherence to prescribed stimulant medications. Conclusion: In this study, adherence at 12 months was better than 6 months, and no significant differences in adherence was observed after including and excluding summer break. Significant predictors of nonadherence included lack of follow-ups, having non-severe ADHD, African-American race, and geographical region – 5. A proper understanding of these predictors will help the development of interventions to improve the medication adherence among ADHD patients