Volume 62 (2015) Issue 1 Pages 77-86
It remains to be seen whether pancreatic β cell dysfunction in type 2 diabetic patients can be ameliorated just by correcting hyperglycemia. The current pilot study investigated β cell function after a four-week treatment with a sodium-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin in Japanese patients with type 2 diabetes mellitus. Ten participants (age, 51 ± 13 years; hemoglobin A1c levels, 9.4 ± 1.0%) took 50 mg of ipragliflozin L-proline for four weeks and thereafter discontinued the agent for one week. A 75-g oral glucose tolerance test (OGTT) was performed at 0 (baseline), 4 (end of medication), and 5 weeks (end of washout). The β cell function was evaluated using the disposition index, which was calculated as the product of the ΔIns0-120/ΔGlu0-120 and the Matsuda index, where ΔIns0-120/ΔGlu0-120 represents the ratio of the incremental concentrations of insulin to those of glucose during the 0- to 120-min time period of the OGTT. The fasting glucose level was 182 ± 34 mg/dL at 0 week, 137 ± 20 mg/dL at 4 weeks (p < 0.001), and 154 ± 31 mg/dL at 5 weeks (p = 0.001). Compared to baseline, the disposition index was significantly elevated not only at 4 weeks (p < 0.001) but also at 5 weeks (p = 0.008). In conclusion, the current pilot study showed that the β cell function assessed by the OGTT-derived disposition index was significantly improved after a four-week treatment with ipragliflozin in Japanese patients with type 2 diabetes mellitus.