OBJECTIVES: To evaluate the real-world persistence and adherence of basal insulin and premixed insulin in Chinese patients with type 2 diabetes mellitus (T2DM) initiating injectable therapies.

METHODS: Adult T2DM patients uncontrolled on oral antidiabetics and initiating injectables between 2019-01-01 and 2021-12-31 were identified from regional electronic health records (EHR). Patients were included if the insulin initiated was basal insulin or premixed insulin. A 6-month baseline period and a 12-month follow-up period were defined. Medication persistence days were defined as the number of days on treatment without discontinuation. Medication persistence was modeled as time to discontinuation and compared using log-rank test. Medication possession days were calculated as the total number of insulin prescription days during the follow-up period and were compared using Wilcoxon rank-sum test. Medication possession days were divided into categories and were compared using Chi-square test.

RESULTS: A total of 5421 patients were included, with 3084 initiated on basal insulin and 2337 on premixed insulin. The mean age was 57.14 ± 12.21 years, and 3007 (57.7%) were male. The discontinuation rates within 12 months were 82.4% for basal insulin and 86.3% for premixed insulin. The median persistence days (95% CI) were 93 (88, 101) for basal insulin and 78 (72, 84) for premixed insulin (log-rank P < 0.0001). The median medication possession days (IQR) were 102 (28, 267) for basal insulin and 70 (28, 208) for premixed insulin (Wilcoxon P < 0.0001). The distribution of patients in the categories 271-365, 181-270, 91-180, 0-90 days is 24.5%, 12.1%, 15.6%, 47.8% for basal insulin and 16.9%, 11.4%, 15.4%, 56.3% for premixed insulin (Chi-square P < 0.0001).

CONCLUSIONS: T2DM patients initiating injectable therapy with basal insulin have better treatment persistence and adherence compared to those initiating on premixed insulin. However, treatment adherence should be improved for both regimens.