Comparison of medication persistence and adherence in type 2 diabetes using a once-weekly regimen of DPP-4 inhibitor compared with once-daily and twice-daily regimens: a retrospective cohort study of Japanese health insurance claims data

Aims Assess medication persistence and adherence for dipeptidyl peptidase-4 inhibitors (DPP-4i) administered once weekly (QW), once daily (QD), and twice daily (BID) among patients with type 2 diabetes (T2D), and explore factors associated with discontinuation and non-adherence for DPP-4i regimens. Methods This retrospective T2D cohort study used medical claims data for three DPP-4i regimens in patients newly prescribed DPP-4i between December 2016 and February 2019. Medication persistence rates were calculated at 3, 6, and 12 months by the Kaplan–Meier method. Adherence was measured as Proportion of Days Covered (PDC). We used Cox proportional hazards models for DPP-4i discontinuation and logistic regression models for non-adherence. Results In the analysis population of 52,762 patients, DPP-4i prescriptions were 84.2% QD, 11.8% BID, and 4.0% QW. Medication persistence rates were similar up to 6 months for all regimens: approximately 90% at 3 and 80% at 6 months. The 12-month persistence rates for QD, BID, and QW were 74.8%, 67.5%, and 68.0%, respectively. Median PDC was 94.0% for QD, 91.8% for BID, and 93.2% for QW. Five specific factors were associated with discontinuation: BID or QW regimen, younger age, no concomitant medications, comorbid dementia, and comorbid chronic pulmonary disease. Non-adherence was associated with those factors plus male sex and treatment at clinics with 0–19 beds. Conclusions The 12-month medication persistence rates were highest for QD, followed by QW and then BID. Adherence was similar for all three regimens. Medication persistence for DPP-4i may be improved by tailoring regimens to patient characteristics and needs.