Randomized controlled trial of single-agent glimepiride and pioglitazone in Japanese patients with type 2 diabetes: A comparative study

Aims/Introduction: To compare first-line, single-agent glimepiride and pioglitazone in Japanese patients with type 2 diabetes uncontrolled by diet and exercise with respect to glycemic control, safety and metabolic changes. Materials and Methods: Patients with previously untreated type 2 diabetes were enrolled in a multicenter, randomized, non-blind, parallel-group trial of glimepiride (0.5-6 mg/day) or pioglitazone (15-45 mg/day) for 6 months. Results: A total of 191 patients aged 30-75 years were randomized. Similar percentages of patients attained the primary end-point, with glycated hemoglobin < 6.9% at month 6 with glimepiride and pioglitazone, respectively (61.2 vs 56.8%, P = 0.64). At month 6, the following significant (P < 0.05) intragroup changes in mean plasma lipid concentrations were noted as compared with baseline: total cholesterol decreased from 203.5 to 195.5 mg/dL and low-density lipoprotein (LDL)-cholesterol decreased from 124.5 to 116.3 mg/dL in the glimepiride group, whereas high-density lipoprotein (HDL)-cholesterol increased from 51.6 to 56.0 mg/dL and triglycerides decreased from 167.6 to 143.6 mg/dL in the pioglitazone group. The only symptomatic adverse events were mild-to-moderate in four patients receiving pioglitazone, and constipation in one patient receiving glimepiride. Similar numbers of patients experienced asymptomatic hypoglycemia (< 60 mg/dL) in the glimepiride and pioglitazone groups (n = 7 and 5, respectively). Conclusions: There was no statistically significant difference between glimepiride and pioglitazone with respect to glycemic control, and both agents were well tolerated. Glimepiride significantly lowered total cholesterol and LDL-cholesterol, whereas pioglitazone increased HDL-cholesterol. This trial was registered with University Hospital Medical Information Network (UMIN), Japan, UMIN000004582. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00115.x, 2011)