Pharmacological Treatment of Insulin Resistance at Two Different Stages in the Evolution of Type 2 Diabetes: Impact on Glucose Tolerance and β-Cell Function

The purpose of this study was to compare the impact of treating insulin resistance with a thiazolidinedione drug before vs. at the onset of diabetes on glucose levels and β-cell function. Nondiabetic Hispanic women of Mexican or Central American descent with prior gestational diabetes mellitus (GDM) were randomized to troglitazone (early intervention), 400 mg/d, or placebo (later intervention). Women who developed diabetes were placed on open-label troglitazone. Glucose tolerance, insulin resistance, and β-cell function were measured at randomization, at the diagnosis of diabetes, and 8 months post trial to determine the long-term impact of the two treatment strategies on glucose levels and β-cell function. During a mean follow-up of 4.3 yr between baseline and posttrial tests, glucose tolerance (oral glucose tolerance test glucose area, P = 0.04) and insulin resistance (MINMOD SI, P = 0.02) worsened more in women randomized to late intervention (n = 69) than to early intervention (n = 57). Insulin secret...