Pioglitazone and Rosiglitazone Have Different Effects on Serum Lipoprotein Particle Concentrations and Sizes in Patients with Type 2 Diabetes and Dyslipidemia Authors:

Objective: Associated with insulin resistance in type 2 diabetes are increased serum triglycerides, decreased HDL-C, and a predominance of large VLDL, small LDL, and small HDL particles. The comparative effects of thiazolidinedione insulin sensitizers on serum lipoprotein particle concentrations and sizes in type 2 diabetes are not known. We studied the effects of pioglitazone (PIO) and rosiglitazone (ROSI) treatments on serum lipoprotein particle concentrations and sizes in type 2 diabetes patients with dyslipidemia. Research Design and Methods: This is a prospective, randomized, double-blind, multicenter, parallel-group study. After a 4-week placebo washout period, patients randomized to PIO (n=369) were treated with 30 mg qd for 12 weeks followed by 45 mg qd for another 12 weeks, while patients randomized to ROSI (n=366) were treated with 4 mg qd followed by 4 mg bid for the same intervals. Lipoprotein subclass particle concentrations and sizes were determined by proton nuclear magnetic resonance spectroscopy at baseline and endpoint (PIO [n=333] and ROSI [n=325] patients). Results: PIO-treatment increased total VLDL particle concentration less than ROSItreatment and decreased VLDL particle size more than ROSI. PIO-treatment reduced total LDL particle concentration whereas ROSI-treatment increased it. Both treatments increased LDL particle size, with PIO-treatment having a greater effect. Whereas PIOtreatment increased total HDL particle concentration and size, ROSI-treatment decreased them; both increased HDL cholesterol levels. Conclusion: PIO and ROSI treatments have different effects on serum lipoprotein subclass particle concentrations and sizes in patients type 2 diabetes and dyslipidemia. Registered in clinicaltrials.gov as NCT00331487