A Real-World Anti-Diabetes Medication Cost Comparison Between Premixed Insulin Analogs and Long-Acting Insulin Analogs in Chinese Patients with Type 2 Diabetes: A Retrospective Database Analysis

Abstract

Introduction: To assess and compare per-day anti-diabetic medication costs for Chinese type-2 diabetes mellitus (T2DM) insulin-naïve patients between those who initiated premixed insulin analogs ("premixed group") and those who initiated long-acting insulin analogs ("long-acting group").

Methods: Data were obtained from an electronic medical record database between 2010.01.01 and 2015.06.30 covering medical encounter records from all general hospitals in a district from Shanghai, China. Insulin-naïve T2DM patients who were aged ≥ 18 years, treated with an oral anti-diabetic drug (OAD) only during the baseline period (3 months prior to insulin initiation), and initiated premixed or long-acting insulin analogs were included. Patients were followed until index insulin discontinuation or 12 months after initiation, whichever came first. The t test and generalized linear models adjusting for propensity score (PS) (including baseline demographics, number of OAD classes, comorbidities, costs, and healthcare resource utilization) were used to examine the differences between the two insulin groups.

Results: A total of 570 and 185 patients were identified for the premixed and long-acting groups, with mean (SD) ages of 63.0 (12.8) and 61.1 (11.9) (P = 0.08) and male proportions of 47.4% and 51.4% (P = 0.35), respectively. During the baseline period, 19.3% of the premixed users had T2DM-related hospitalizations, while the rate was 12.4% in the long-acting group (P = 0.03). The mean number of T2DM-related outpatient visits was 0.98 and 1.23 for the premixed and long-acting groups, respectively (P = 0.07). During the follow-up period, the per-day insulin dose averaged 31.7 and 15.3 international units (IU) for the premixed and long-acting groups, respectively. Compared with the patients on premixed insulin, the mean per-day cost for patients on long-acting insulin was 37.3% higher [15.3 vs 11.2 Chinese yuan (RMB); mean difference (MD) (95% CI): 4.2 (3.2, 5.1)] for the overall anti-diabetes medication, 81.3% higher [3.3 vs 1.8 RMB; MD (95% CI): 1.5 (0.8, 2.2)] for OAD, and 28.6% higher [12.0 vs 9.3 RMB; MD (95% CI): 2.7 (2.1, 3.3)] for insulin. The results were consistent after adjusting for the PS.

Conclusion: Among Chinese T2DM insulin-naïve patients, those who initiated premixed insulin had a lower per-day antidiabetic medication cost than those who initiated long-acting insulin.

Funding: Lilly Suzhou Pharmaceutical Co. Ltd, China.

Keywords: China; Cost; Insulin analog; Type 2 diabetes mellitus.

Fig. 1

Patient flow chart

Fig. 2

Oral antidiabetic drug exposure during the six months following insulin initiation

Fig. 3

Per-day cost (in RMB)

Fig. 4

Per-day cost (in RMB) for those with a daily insulin dose of ≥ 20 IU