Background: The aim of this study is to explore appropriate indicators for the efficacy of pioglitazone (Pio) before and during treatment of Japanese patients with type 2 diabetes mellitus (T2DM).
Methods: Forty-eight Japanese patients with T2DM (22 men, 26 women, 60 +/- 2 years old) were enrolled and treated with 15 mg/day of Pio for 12 weeks. Before and after the treatment, various parameters were evaluated regarding the efficacy of Pio. Patients who had a reduction in hemoglobin A1c (HbA1c) of >1% after 12 weeks of treatment were defined as responders.
Results: Twenty-two patients were classified as responders. In the responder group, age, fasting plasma glucose (FPG), and percentage female were significantly (P < 0.05) higher compared with the non-responder group. In logistic regression analysis, female sex and higher FPG were selected as explanatory variables for the efficacy of Pio. Furthermore, the change of HbA1c (DeltaHbA1c) was positively correlated with that of fasting C-peptide level (DeltaCPR) and log-transformed high-sensitivity C-reactive protein (Deltalog HS-CRP), and negatively correlated with that of high-density lipoprotein cholesterol (DeltaHDL-C) and log-transformed adiponectin (Deltalog AP). In multiple stepwise regression analysis, DeltaCPR, Deltalog HS-CRP, and Deltalog AP (or DeltaFPG) were selected as explanatory variables for DeltaHbA1c.
Conclusions: We concluded that Pio is likely to show favorable effects on blood glucose control especially in female patients with higher FPG levels. Administration of Pio ameliorates blood glucose control accompanied by the increase of AP and the decrease of CPR or HS-CRP, suggesting that Pio exerts its beneficial effects through the enhancement of AP, which leads to suppression of inflammation and amelioration of insulin resistance.