Thiazolidinediones Can Prevent And Postpone Type 2 Diabetes Significant improvement in HbA1c levels from baseline were found in patients treated with TZDs Two second-generation thiazolidinediones, rosiglitazone and pioglitazone, are effective at preventing or postponing the progression of impaired glucose tolerance or insulin resistance to type 2 diabetes mellitus.
A total of 172 patients (aged 29 to 86 years) were recruited for this study. In the treatment group, 101 patients received troglitazone for an average of 10 months (range 3-27 months) following which 39 patients were switched to rosiglitazone and the remaining 62 patients were switched to pioglitazone.
"Patients were switched when troglitazone [a thiazolidinedione (TZD)] was withdrawn from the US market because of liver toxicity concerns," explains R. J. Durbin, MD, South Federal Family Practice, Denver, Colorado, United States. The 71 patients in the control group did not receive any antidiabetic medication during the study.
The mean duration of the study was 36 months. HbA1c and C-peptide levels were measured at baseline (2 years) and study end point (3 years).
Patients who had normal or borderline HbA1c, elevated C-peptide (above 2.0 mg/mL), fasting blood sugar (FBS) between 100 and 125 mg/dL and 2-hour postprandial blood glucose levels between 140 and 200 mg/dL were considered to be both IGT and IR.
Analysis showed that rosiglitazone and pioglitazone reduced hemoglobin A1c (HbA1c) and C-peptide levels in patients with impaired glucose tolerance (IGT) or insulin resistance (IR).
Mean baseline HbA1c levels were 6.12 ± 0.60% and 6.23 ± 0.74% for patients receiving rosiglitazone and pioglitazone, respectively, and 6.18 ± 0.20% for patients in the control group.
At the final visit, mean HbA1c levels were 5.57 -/= 0.37% and 5.65 ± 0.48% for patients receiving rosiglitazone and pioglitazone respectively, and 6.68 ± 0.19% for patients in the control group.
"Significant improvement in HbA1c levels from baseline were found in patients treated with TZDs (P < .001)," the author reports. "There was a significant difference in mean reduction of HbA1c levels between the TZD-treated groups and the control group (P < .001)."
Mean baseline C-peptide values were 3.39 ± 1.70 mg/mL and 3.90 ± 1.94 mg/mL for patients receiving rosiglitazone and pioglitazone, respectively, and 3.56 ± 0.57 mg/mL in the control group. At the final visit, mean C-peptide levels were 1.69 ± 0.53 mg/mL and 1.84 ± 0.70 mg/mL for patients receiving rosiglitazone and pioglitazone, respectively, and 4.46 ± – 0.59 mg/mL for patients in the control group.
At the 2-year assessment, no patients treated with TZDs had progressed to diabetes, compared with 11 patients in the control group. Only 3 patients in the treatment group developed diabetes by the end of the study, compared with 19 patients in the control group.
The estimated cumulative incidence rate of diabetes after 3 years was lower for the TZD group (2.97%) than for the control group (26.8%). "These findings support the concept that rosiglitazone and pioglitazone may be used as an early pre-symptomatic treatment for individuals at risk of T2DM [type 2 diabetes mellitus]", the author concludes. Diabetes Obes Metab 2004 Jul;6:4:280-5
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