Differential Effects of Pioglitazone on Metabolic Parameters in Newly Diagnosed, Drug-Naïve Japanese Patients with Type 2 Diabetes with or Without Metabolic Syndrome

Abstract

Objective. The aim of this study was to evaluate the efficacy of pioglitazone on metabolic parameters in drug-naïve Japanese type 2 diabetic patients with (Diabetes Mellitus Metabolic Syndrome [DMMS] group, n = 36) and without (Diabetes Mellitus non-Metabolic Sundrome [DMNMS] group, n = 36) metabolic syndrome. Patients and Methods. The patients received monotherapy of 15–30 mg/day pioglitazone for 3 months. The baseline levels of metabolic parameters were compared with the levels after 3 months. Results. At baseline, the two groups showed no significant difference in HbA1c (10.05 vs. 9.81%, n.s.) or systolic blood pressure (134.5 vs. 133.0 mmHg, n.s.), but had significant differences in diastolic blood pressure (84.7 vs. 78.9 mmHg, p < 0.05), insulin (14.96 vs. 7.09 μU/mL, p < 0.001), homeostasis model assessment insulin resistance index (HOMA-R) (8.49 vs. 3.96, p < 0.001), triglyceride (TG) (231.4 vs. 131.5 mg/dL, p < 0.0005), high-density lipoprotein (HDL)-C (46.6 vs. 56.1 mg/dL, p < 0.005), body weight (BW) (77.97 vs. 62.52 kg, p < 0.001), and body mass index (BMI) (28.14 vs. 22.86, p < 0.00001). In the DMMS group, significant changes of HbA1c (from 10.05 to 8.01%, p < 0.00001), insulin (−22.7%, p < 0.05), HOMA-R (−48.9%, p < 0.0002), TG (−20.8 %, p < 0.05), HDL-C (+12.0%, p < 0.00001), BW (+1.0 kg/+1.3%, p < 0.05), and BMI (+1.4%, p < 0.02) were observed after 3 months. In the DMNMS group, the reduction of HbA1c (from 9.81 to 8.33%, p < 0.00001) was similar to that in the DMMS group, but the changes of insulin (−4.7%, n.s.), HOMA-R (−15.6%, n.s.), and TG (−12.9%, n.s.) were smaller and not significant. Significant increases of HDL-C (+9.2%, p < 0.02), BW (+0.64 kg/+1.0%, p < 0.05), and BMI (+1.0%, p < 0.02) were observed, but these changes were also smaller than the respective changes in the DMMS group. Based on the change of each parameter relative to its baseline value, significant intergroup differences were found for TG, insulin, or HOMA-R, whereas no such differences were observed for HDL-C, BW, and BMI. No subjects showed any clinically significant adverse events. Conclusions. These results suggest that the glucose-lowering effect of pioglitazone is comparable in patients with type 2 diabetes with or without metabolic syndrome, but that the drug has different effects on nonglycemic parameters including TG, insulin and HOMA-R in the two groups of patients.

Keywords:

• Insulin resistance
• Metabolic syndrome
• Thiazolidinedione
• Pioglitazone

ACKNOWLEDGMENTS

The author thanks Drs. Jan Wajs, Shinichi Sakurai, Hiroyuki Tabata, and Naoki Takeda for valuable comments and discussion.

Declaration of Interest: The author declares that there are no conflicts of interests regarding this work.