Relationship of Insulin Dose, A1c Lowering, and Weight in Type 2 Diabetes: Comparing Insulin Glargine and Insulin Detemir

Background: A pooled analysis of randomized controlled trials of individuals with type 2 diabetes mellitus (T2DM) was conducted to compare dosing and impact of two basal insulin analogs, insulin glargine (glargine) and insulin detemir (detemir), on weight and hemoglobin A1c (A1c). Methods: Twenty-two studies of at least 20 weeks in duration in individuals with T2DM initiating glargine/detemir were included. Results were combined using a weighted-average method and a bivariate random effect model. Outcomes included changes in weight, A1c, and insulin dose from study start to end. Results: One study was head-to-head comparison of glargine and detemir. Detemir (four studies) was administered once or twice daily, with 50% starting on detemir once daily but needing therapy intensification. Glargine was used once daily in all 22 studies. The Egger test was borderline significant for change in weight over the course of the treatment for glargine (0.29; 90% confidence interval [CI] -0.01, 0.58), and heterogeneity was not observed for detemir (-0.18; 90% CI -0.59, 0.23). Heterogeneity was observed for change in A1c over the course of the treatment (glargine, -1.19, 90% CI -1.74, -0.63; detemir, -2.65, 90% CI -4.86, -0.45). Nonheterogeneity for change in A1c over the course of the treatment was achieved by excluding five studies for glargine and one study for detemir; however, all studies were included in subsequent analyses. In the unadjusted model, glargine and detemir showed similar results for mean A1c change (-1.4% vs. -1.4%), weight gain (2.5 vs. 1.7 kg), and weight/A1c (1.8 vs. 1.2 kg/%). A significantly higher detemir dose was needed to achieve the same A1c change (51.5 vs. 38.8 U/day). Conclusions: Although absolute weight gain was higher with glargine versus detemir, weight gain per A1c change was similar. A higher detemir dose was required to achieve a similar A1c reduction.