Oral antidiabetic drugs and regression from prediabetes to normoglycemia: a meta-analysis.

BACKGROUND Impaired glucose tolerance, impaired fasting glucose, and elevated hemoglobin A(1c) are intermediate stages, considered prediabetes, a precursor to overt type 2 diabetes mellitus. Prediabetes is associated with increased risk for cardiovascular disease, independent of diabetes development. Data have shown that various oral antidiabetic drugs can help people regress from prediabetes to normoglycemia. OBJECTIVE To evaluate the efficacy of oral antidiabetic drugs in promoting regression from prediabetes to normoglycemia. METHODS MEDLINE (1950-November 2011), EMBASE (1990-November 2011), and Cochrane Central Register of Controlled Trials (indexed September 2011) were systematically searched. A manual search of references from reports of clinical trials and review articles was performed to identify additional relevant studies. Randomized controlled trials 12 weeks or more in duration evaluating any of the oral antidiabetic drugs and studying regression from prediabetes to normoglycemia were included. A random-effects model was used to calculate pooled odds ratios with 95% confidence intervals. RESULTS Thirteen studies (N = 11,600 participants) were included in the meta-analysis. Use of oral antidiabetic drugs in prediabetic patients was shown to double the odds of achieving normoglycemia compared to controls (OR 2.03, 95% CI 1.54 to 2.67). When individual classes of oral antidiabetic drugs were evaluated, use of thiazolidinediones (OR 2.33, 95% CI 1.93 to 2.81) and α-glucosidase inhibitors (OR 2.02, 95% CI 1.26 to 3.24) was associated with significantly increased odds. However, biguanides (OR 2.04) and sulfonylureas (OR 1.84) failed to reach statistical significance (p = 0.06 and p = 0.39, respectively). CONCLUSIONS In patients with prediabetes, oral antidiabetic drugs were associated with increased odds of regression to normoglycemia versus placebo/control. Only thiazolidinediones and α-glucosidase inhibitors provided a statistically significant increase in odds of regressing to normoglycemia.