Endocrine Abstracts

Background: The anti-hyperglycemic effects of thiazolidinedione/biguanide combination therapy are well established. However, the impact of such therapy on other clinical risk factors for cardiovascular disease (CVD) has not been extensively reported.

Objective: To evaluate the anti-hyperlipidemic effects of pioglitazone (PIO) and rosiglitazone (ROSI) used in combination with metformin (MET) in patients with type 2 diabetes, a multicenter, retrospective, randomly selected chart review was conducted in U.S. endocrinology practices. Patients (>=18 years old) receiving MET (>=1000mg/day) and adjunctive PIO (30mg/day or 45mg/day) or ROSI (4mg/day or 8mg/day) were included in the study. Inclusion/exclusion criteria were established to minimize the potential confounding effect of independent variables (eg, concomitant medications, duration of study drug therapy, change in treatment regimen, and timing of laboratory assessments).

Results: Among 193 patients (MET+PIO, n=97; MET+ROSI, n=96) who qualified for analyses, cohort demographics (including comorbidities, concomitant medications, and pre-treatment HbA_1c and lipid levels) were similar between study groups. Patients receiving MET+PIO had significant changes between pre-treatment baseline and post-treatment follow-up (P<0.05) in triglyceride (-0.55 mmol/L), HDL-C (+0.08 mmol/L), and LDL-C (+0.13 mmol/L) concentrations; baseline-to-follow-up change for total cholesterol (+0.04 mmol/L) was not significant. Patients receiving MET+ROSI experienced significant baseline-to-follow-up changes in total cholesterol (+0.30 mmol/L) and LDL-C (+0.18 mmol/L) concentrations; changes in triglyceride (+0.24 mmol/L) and HDL-C (+1.6 mmol/L) concentrations were not significant. The difference in the change from baseline-to-follow-up in triglyceride and total cholesterol concentrations between MET+PIO and MET+ROSI cohorts was also significant, (P<0.05). Mean baseline-to-follow-up change in HbA_1c (MET+PIO, -0.8%; MET+ROSI, -0.9%) did not differ between study groups.

Conclusions: Patients receiving MET+PIO may realize greater lipid improvement than patients receiving MET+ROSI. These favorable changes in both triglyceride and cholesterol concentrations are important when making therapeutic decisions that may minimize the risk of CVD complications associated with type 2 diabetes, insulin resistance and/or the metabolic syndrome.