Comparison of effect of pioglitazone with metformin or sulfonylurea (monotherapy and combination therapy) on postload glycemia and composite insulin sensitivity index during an oral glucose tolerance test in patients with type 2 diabetes.

Objective: Pioglitazone, metformin, and gliclazide lower HbA(1c) and fasting plasma glucose in patients with type 2 diabetes. We compared the effects of these three drugs, used as monotherapy and in combination, on postload glycemia and composite insulin sensitivity index (CISI) in these patients.

Research Design And Methods: Postload glycemia and CISI were analyzed for 940 patients who had oral glucose tolerance tests (OGTTs) in four multicenter, randomized, double-blind, double-dummy, parallel group clinical trials (pioglitazone versus metformin, pioglitazone versus gliclazide, pioglitazone plus sulfonylurea versus metformin plus sulfonylurea, and pioglitazone plus metformin versus gliclazide plus metformin).

Pioglitazone as monotherapy or in combination with sulfonylurea or metformin enhances insulin sensitivity (HOMA-S or QUICKI) in patients with type 2 diabetes.

Background: Miyazaki et al. demonstrated using the hyperinsulinemic, euglycemic clamp that pioglitazone (PIO) enhanced insulin sensitivity in patients (n = 23) with type 2 diabetes (T2D). Although considered the reference method for measuring insulin sensitivity, the clamp is seldom used in large clinical trials because of its complexity.