Glycemic variability is associated with the development of diabetic complications and hypoglycemia. However, the effect of sodium-glucose transporter 2 (SGLT2) inhibitors on glycemic variability is controversial. We aimed to examine the effect of dapagliflozin as an add-on therapy to insulin on the glycemic variability assessed using continuous glucose monitoring (CGM) in subjects with type 2 diabetes mellitus.

In this multicenter, placebo-controlled, double-blind, randomized study, 84 subjects received 10 mg of dapagliflozin (n=41) or the placebo (n=43) for 12 weeks. CGM was performed before and after treatment to compare the changes in glycemic variability measures (standard deviation [SD], mean amplitude of glycemic excursions [MAGEs]).

At week 12, significant reductions in glycosylated hemoglobin (−0.74%±0.66% vs. 0.01%±0.65%, P<0.001), glycated albumin (−3.94%±2.55% vs. −0.67%±2.48%, P<0.001), and CGM-derived mean glucose (−41.6±39.2 mg/dL vs. 1.1±46.2 mg/dL, P<0.001) levels were observed in the dapagliflozin group compared with the placebo group. SD and MAGE were significantly decreased in the dapagliflozin group, but not in the placebo group. However, the difference in ΔSD and ΔMAGE failed to reach statistical significance between two groups. No significant differences in the incidence of safety endpoints were observed between the two groups.

Dapagliflozin effectively decreased glucose levels, but not glucose variability, after 12 weeks of treatment in participants with type 2 diabetes mellitus receiving insulin treatment. The role of SGLT2 inhibitors in glycemic variability warrants further investigations.