Comparative study of sitagliptin with pioglitazone in Japanese type 2 diabetic patients: the COMPASS randomized controlled trial

Aims To compare the efficacy and safety of these two agents and the impact on surrogate markers related to diabetic complications in Japanese type 2 diabetic patients. Methods In a multicenter, open-label trial, 130 patients whose diabetes had been inadequately controlled (HbA1c, 6.99.5%) with metformin and/or sulphonylurea were randomly assigned to a sitagliptin group (50mg/day) or a pioglitazone group (15mg/day) and were followed up for 24weeks. At 16weeks, if the patient's HbA1c level was 6.5%, the dose of sitagliptin or pioglitazone was increased up to 100 or 30mg/day, respectively. Main outcome measure was the difference in the mean changes in the HbA1c level from baseline at 24weeks between these two groups. Results Of the 130 patients who were enrolled, 115 subjects (sitagliptin group: 58 patients, pioglitazone group: 57 patients) completed this trial. At 0weeks, the mean HbA1c level was 7.47 +/- 0.66% in the sitagliptin group and 7.40 +/- 0.61% in the pioglitazone group. At 24weeks, the mean changes in the HbA1c level from baseline were 0.86 +/- 0.63% versus 0.58 +/- 0.68% (p=0.024). Hypoglycaemia (2 patients, 3.4% vs. 2 patients, 3.5%), gastrointestinal symptoms (3 patients, 5.2% vs. 1 patient, 1.8%) and pretibial oedema (0 patients, 0% vs. 39 patients, 68.4%, p<0.001) were observed for 24weeks. Conclusions Sitagliptin was not only more tolerable, but also more effective than pioglitazone in Japanese type 2 diabetic patients who had been treated with metformin and/or sulphonylurea.