First-year oral antidiabetic adherence and long-term complications in newly diagnosed type 2 diabetes

Aims: Type 2 diabetes (T2D) is a growing public health issue, with early treatment adherence potentially impacting long-term outcomes. This study assessed the association between adherence to oral antidiabetic drugs (OADs) during the first year after diagnosis and the risk of complications and mortality. Methods: A retrospective cohort study was conducted using a nationally representative health claims database. Patients newly diagnosed with T2D in 2009 who initiated OAD monotherapy within 12 months were included. Follow-up continued from the adherence index date until death, loss of follow-up, or study end. Patients were categorized by adherence level during the first year: good (≥ 80 %) and poor (< 80 %). Outcomes included macrovascular events, diabetes-related hospitalizations, and all-cause mortality. Hazard ratios were estimated using Cox proportional hazards models with inverse probability of treatment weighting. Results: Among 65,340 patients, 46.9 % (n = 30,657) showed good adherence. Compared to poor adherence, good adherence was associated with a 23 % lower risk of macrovascular events, an 8% lower risk of diabetes-related hospitalizations, and a 28 % lower risk of all-cause mortality. Conclusions: Early adherence to OADs was associated with a reduced risk of complications and mortality in T2D patients. Promoting adherence in newly diagnosed individuals is crucial for improving long-term outcomes.