Pioglitazone plus a sulphonylurea or metformin is associated with increased lipoprotein particle size in patients with type 2 diabetes

Abstract

Objective To determine the effect of pioglitazone plus metformin or a sulphonylurea on lipoprotein particle size and subclass distribution in patients with type 2 diabetes. Methods Lipid profiles were determined for blood samples from patients participating in two randomised, double-blind, 24-week studies of pioglitazone 30 mg or 45 mg daily plus either metformin or a sulphonylurea. Results Samples from 177 patients were evaluated; 96 of these patients received a sulphonylurea, and 81 received metformin. Pioglitazone combination treatment produced significant increases from baseline for average and peak low-density lipoprotein (LDL) particle size at weeks 12 and 24 (p<0.0001 for each; range 0.29–0.39 nm for average and 0.36–0.55 nm for peak particle size, respectively). Significant shifts in high-density lipoprotein (HDL) and LDL distribution showed an increase in large particles and a decrease in small particles. For pioglitazone plus metformin, significant increases in levels of apolipoprotein (Apo) AI, Apo AI/AII-containing HDL, and lipoprotein(a) also were noted, whereas Apo B levels decreased. Conclusions These observed changes are thought to affect the atherogenic profile positively. Therefore, pioglitazone combination treatment may lead to decreased cardiovascular risk in patients with type 2 diabetes.