Alexandra C. Gillett, Dale Handley, Renu Bala, Katherine Young, Jessica Tyrrell, Cathryn M. Lewis
AIMS: To investigate the association between depression history, timing, and progression of diabetes treatment in type 2 diabetes (T2D). METHODS: We conducted a cohort study using primary care records from the Clinical Practice Research Datalink Aurum database (2011-2023). Adults with T2D initiating oral glucose-lowering monotherapy (index) were included. Depression history, identified using clinical codes, was categorised by the most recent code before index: recent (≤1.7 years), intermediate (1.7-12.8 years), distant (>12.8 years), or none. Outcomes were time to treatment intensification (adding or switching drug class) and insulin initiation. We used Royston-Parmar survival models to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for demographic and clinical variables. RESULTS: Among 378,935 included individuals, 25.1% had a history of depression. Compared with no prior depression, recent depression was associated with higher odds of treatment intensification (OR 1.20, 95% CI: 1.17-1.23) and insulin initiation (OR 1.29, 95% CI: 1.23-1.36). Intermediate and distant depression were also associated with higher progression-odds, but effect sizes were small, particularly for distant depression. CONCLUSIONS: Depression, particularly recent episodes, is associated with earlier treatment progression in T2D, highlighting the importance of integrating mental and physical healthcare in diabetes management.