Trends in Diabetes Medication Taking and Incidence of Depression in Patients with Type 2 Diabetes: A Retrospective Cohort Study from 2010 to 2018.

Background: This study examined the trends in diabetes medication taking and its association with the incidence of depression in patients with type 2 diabetes (T2D).

Method: A retrospective cohort of Medicare enrollees with regular care in 2010 was defined from 100% Texas Medicare claims. The impact of medication taking on incident depression was evaluated from 2010 to 2018. Cox proportional hazards regressions were used to estimate the association between medication taking and depression.

Results: A total of 72,461 patients with T2D and with regular care were analyzed. Among 60,216 treated patients, the regular medication taking rate slightly increased from 60.8 to 63.2% during the study period. Patients with regular medication taking at baseline had a 9% lower risk of developing depression (hazard ratio [HR]: 0.91, 95% confidence interval [CI]: 0.89-0.94), and the magnitude of the association increased after adjustment of the model for time-varied medication taking (HR: 0.82, 95% CI: 0.79-0.85). The presence of nephropathy had the greatest mediating effect (23.2%) on the association of medication taking and depression.

Conclusion: We demonstrated a steady but modest increase in regular diabetes medication taking over a 9-year period and a significant relationship between medication taking and incident depression in patients with T2D.