Objective: To estimate the adherence of children and adults to oral stimulant ADHD treatments in Sweden during the period 2015 to 2020. Methods: This retrospective, nationwide, register-based study evaluated all patients who were dispensed oral formulation stimulants (Anatomical Therapeutic Chemical ATC codes: N06BA01, N06BA02, N06BA04, N06BA12) identified in the Swedish Prescribed Drug Register. Treatment episodes were constructed based on drug dispensation data, and treatment adherence was calculated for each treatment episode using a Proportion of Days Covered approach with a modified one-pill-a-day method. Results: Between 2015 and 2020, 158,413 treatment episodes were recorded in 128,366 patients, corresponding to a median 1.23 treatment episodes per patient. The majority of treatment episodes involved methylphenidate (64.0%), followed by lisdexamfetamine (32.2%), dexamfetamine (3.0%), and amphetamine (0.8%). Overall treatment adherence was high (78.2%), and was similar for patients receiving methylphenidate, lisdexamfetamine, and dexamfetamine. The proportion of patients with ≥80% medication adherence was high (69.3%–71.8%) for adults aged ≥25 years, but was low for adolescents aged 12 to 17 years (49.7%–52.4%). Conclusions: The overall rates of treatment adherence are high for children and adults receiving ADHD medication in Sweden. We observed lower adherence among adolescents, which warrants further study.
Giacobini et al. (Wed,) studied this question.