Fat redistribution preferentially reflects the anti-inflammatory benefits of pioglitazone treatment

Thiazoledinedione is known to have an anti-inflammatory effect besides a hypoglycemic effect. We investigated changes in high-sensitivity C-reactive protein (hsCRP), a proinflammatory marker, after pioglitazone treatment in association with the resulting changes in various metabolic and anthropometric parameters. A total of 93 type 2 diabetes mellitus patients (47 men and 46 women; mean age, 50.0 ± 10.8 years) who were being treated with a stable dose of sulfonylurea or metformin were enrolled in the study. Pioglitazone (15 mg/d) was added to their treatment regimen for 12 weeks, and metabolic and anthropometric measurements were taken before and after pioglitazone treatment. Pioglitazone treatment for 12 weeks decreased serum hsCRP levels (0.83 [1.14] to 0.52 [0.82] mg/L, P < .001) and improved glycemic control (fasting glucose, P < .001; glycosylated hemoglobin, P < .001) and lipid profiles (triglyceride, P = .016; high-density lipoprotein cholesterol, P < .001). Between responders and nonresponders to the hsCRP-lowering effect of pioglitazone, there were significant differences in baseline hsCRP levels and changes in the postprandial glucose and the ratio of visceral fat thickness (VFT) to subcutaneous fat thickness (SFT) (P = .004, .011, and .001, respectively). The percentage change in hsCRP levels after treatment was inversely correlated with baseline hsCRP levels (r = -0.497, P < .001) and directly correlated with the change in postprandial glucose (r = 0.251, P = .021), VFT (r = 0.246, P = .030), and VFT/SFT ratio (r = 0.276, P = .015). Logistic regression analysis revealed that the hsCRP-lowering effect of pioglitazone was affected by baseline hsCRP levels (odds ratio [OR] = 7.929, P = .007) as well as changes in postprandial 2-hour glucose (OR = 0.716, P = .025) and VFT/SFT ratio (OR = 0.055, P = .009). In conclusion, treatment with pioglitazone produced an anti-inflammatory effect, decreasing serum hsCRP levels; and a decrease in the VFT/SFT ratio was independently and most strongly associated with the hsCRP-decreasing effect. These results suggest that abdominal fat redistribution preferentially reflects the anti-inflammatory benefits of pioglitazone treatment.