['The goal was to investigate the interrelationships between the hypoglycemic effects of rosiglitazone and the changes in the regional adiposity of type 2 diabetic patients.', 'We added rosiglitazone (4 mg/day) to 173 diabetic patients (111 males and 62 females) already taking a stable dose of conventional antidiabetic medications except for thiazolidinediones. The abdominal fat distribution was assessed by ultrasonography at baseline and 12 weeks later. Using ultrasonographic images, the s.c. and visceral fat thickness (SFT and VFT respectively) were measured.', 'Rosiglitazone treatment for 3 months improved the glycemic control. However, the response to rosiglitazone was no more than 36.4%; the deterioration of the glycemic control was found in 16.8% of subjects. In addition, rosiglitazone treatment significantly increased the body fat mass, especially the s.c. fat. However that did not alter the visceral fat content. The percentage changes in fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) concentrations after treatment were inversely correlated with the increase in SFT (r=-0.327 and -0.353, P<0.001 respectively) and/or body weight (r=-0.316 and -0.327, P<0.001 respectively). Multiple regression analysis revealed that the improvement in the FPG after rosiglitazone treatment was correlated with the baseline FPG (P<0.001) and the change in the SFT (P=0.019), and the reduction in the HbA1c was related with the baseline FPG (P=0.003) and HbA1c (P<0.001) and the changes in the SFT (P=0.010) or VFT (P=0.013).'] Is the increase in abdominal subcutaneous fat depot an independent factor to determine the glycemic control after rosiglitazone treatment?