The Effect of Rosiglitazone on Poorly Controlled Diabetes in Patients Taking Three Oral Antidiabetic Agents

Abstract

Background/Purpose. To evaluate the effects of rosiglitazone in treating patients whose type 2 diabetes was poorly controlled with an α-glucosidase inhibitor (i.e., acarbose), a biquanide (i.e., metformin), and an insulin secretagogue. Methods. We studied 20 patients in whom type 2 diabetes was poorly controlled with the combination of acarbose, metformin, and an insulin secretagogue. Rosiglitazone (4 mg/day) was added to the treatment regimen for 12 weeks. The dosage of Rosiglitazone was increased to 8 mg/day in patients whose fasting plasma glucose (FPG) level remained ＞150 mg/dL during the first 4 weeks of the study. The hemoglobin A1c (HbA1c) and FPG levels were compared before and after starting rosiglitazone. Patients were stratified into two groups (a more-response group (n=10) and a less-response group (n=10)) medially based on changes in HbA1c-level. Differences in HbA1c and FPG levels before and after adding rosiglitazone were compared between the two groups. Results. There were no significant differences in mean FPG levels (222±44 mg/dL vs 211±50 mg/dL, p=0.12) and mean HbA1c-levels (9.3 1.8% vs 9.0 1.7%, p=0.32) before and after adding rosiglitazone, respectively, in the 20 patients. A significant decrease in HbA1c-levels (9.3 2.2% to 8.1 1.4% (p=0.02)) and FPG levels (214±36 mg/dL to 186±37 mg/dL (p=0.01)) was seen in the more-response group. After 12 weeks of administering rosiglitazone, the HbA1c level decreased by more than 1% in four patients (40%) and was lower than 7% in three patients (30%) in this group. Although HbA1c-levels (9.3±1.5% to 9.8±1.7% (p=0.06)) and FPG levels (231±51 mg/dL to 238±49 mg/dL (p=0.54) increased after adding rosiglitazone in the less-response group, the differences were not significant. There were no significant differences in baseline characteristics except for body weight between the two groups (53.7±8.8kg vs 71.8±11.8kg, p=0.004). At the end of the 12-week period, the mean HbA1c level differed significantly between the more-response group and the less-response group (8.1±1.4% vs 9.8±1.7%, p=0.01); the mean FPG level also differed between the two groups (186±37 mg/dL vs 238±49 mg/dL, p=0.01). Conclusion. Administration of rosiglitazone did not lead to a significant improvement in blood glucose levels. However, our results show that rosiglitazone can help improve glycemic control in some patients when it is added to a combination therapy of acarbose, metformin, and an insulin secretagogue. Baseline body weight is a parameter that can predict response to this oral antidiabetic agent.