Adherence to multiple medications in the TODAY (Treatment Options for type 2 Diabetes in Adolescents and Youth) cohort: effect of additional medications on adherence to primary diabetes medication

Background Non-adherence to diabetes medication leads to poor outcomes and increased healthcare costs. Multiple factors affecting adherence in adults with type 2 diabetes (T2D) have been identified, but pediatric data is sparse. We aimed to determine whether initiation of additional oral medications or insulin affects adherence to primary study medication (PSM) in the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study. Methods Six hundred and ninety-nine youth (aged 10-17 years) with recent-onset T2D were randomized in the TODAY study. Participants were categorized as adherent (>/=80% taken by pill count) or non-adherent (<80%), and adherence was compared between those on additional medications or not. Subgroup analyses to assess influence of race/ethnicity, gender, medication type, or depression were performed. Results At 36 months, 46.3% of participants were taking additional oral medications and 31.9% were on insulin. There was no difference in study medication adherence with additional oral medications (55.1%, 67.1%, and 56.7% at month 36 in those prescribed 0, 1, or 2+ additional medications; p = 0.16). Girls on oral contraceptives (OC) had higher adherence (65.2% vs. 55.8% at month 36; p = 0.0054). Participants on insulin had lower adherence (39.7% vs. 59.3% at 36 months; p < 0.0001). There was decreased adherence in participants with baseline depression (p = 0.008). Conclusions Additional oral medications did not influence adherence to diabetes medications in TODAY. Addition of insulin led to reduced adherence. In subgroup analyses, OC use was associated with higher adherence in girls, while baseline depression was associated with lower adherence overall. Further studies examining potentially modifiable risk factors of adherence in pediatric T2D are needed.