Hsia SH et al. – Among ethnic minority type 2 diabetic patients poorly controlled on maximum tolerated doses of metformin and sulfonylureas, third–line add–on therapy with a thiazolidinedione (TZD) controlled hyperglycemia more effectively than sitagliptin after 4 months.

• In an open–label, single arm design, the authors treated 108 type 2 diabetic subjects who were sub–optimally controlled on maximum tolerated doses of metformin plus sulfonylureas with addition of sitagliptin 100 mg daily, and compared their responses against a historical control group of 104 similar patients treated with rosiglitazone (8 mg) or pioglitazone (45 mg) daily as their third–line oral agent.
• Subjects were assessed bi–monthly, and those who achieved HbA1c < 7.5% at 4 months were continued through 1 year of follow–up.

• At baseline, sitagliptin– and TZD–treated subjects had identical HbA1c (±SD) levels (9.4 ±1.8% and 9.4 ±1.9%, respectively) and similar known diabetes duration (6.7 ±5.0 and 7.6 ± 5.8 years, respectively).
• HbA1c was reduced in both groups at 4 months (p<0.001), but the reduction was greater with TZDs than sitagliptin (–2.0 ±1.7% vs. –1.3 ±1.8%; p=0.006), as was the proportion of subjects achieving HbA1c < 7.5% (61.5% vs. 46.1%; p=0.026).
• Of all subjects achieving HbA1c < 7.5% at 4 months, the same proportions in each group sustained their Hb1c < 7.5% by 12 months (59.1% vs. 57.8%). Sitagliptin was well tolerated.