Medication utilization among adult patients with attention-deficit/hyperactivity disorder after reimbursement...

This study analyzed the pattern of attention-deficit/hyperactivity disorder (ADHD) medication initiation in adult patients with ADHD after the reimbursement criteria change and identified the influencing factors associated with it using the claim data. We identified 243 adult patients with ADHD who had not been prescribed ADHD drugs before 1 September 2016. We conducted Kaplan-Meier survival analysis to calculate the time to initial prescription of ADHD medications, and Cox proportional hazard regression analysis to estimate the influencing factors. Approximately one-third of the patients (n = 76, 31.3%) were first prescribed ADHD medications after reimbursement approval, and 40 of them (16.5%) started treatment with osmotic release oral system methylphenidate. The patient's age group (30-39 years) and the status of diagnosis before the index date were associated with early initiation of pharmacotherapy. The odds of starting ADHD medications increased approximately 2.7-fold in the 30-39 age group and 0.2-fold in the case of patients who were diagnosed before the approval. Our findings show that both diagnosis and treatment of adult ADHD remains inadequate despite the change in reimbursement criteria. Improving awareness of adult ADHD among both the public and the professionals is essential to increase its chances of diagnosis and treatment.