Diabetes Incidence and Glucose Tolerance after Termination of Pioglitazone Therapy: Results from ACT NOW

Context: Thiazolidinediones have proven efficacy in preventing diabetes in high-risk individuals. However, the effect of thiazolidinediones on glucose tolerance after cessation of therapy is unclear. Objective: To examine the effect of pioglitazone (PIO) on incidence of diabetes after discontinuing therapy in ACT NOW. Design, Settings and Patients: Two-hundred ninety-three subjects (placebo [PLAC], n = 138; PIO, n = 152) completed a median followup of 11.7 mo after study medication was stopped. Results: Diabetes developed in 138 (12.3%) of PLAC vs 17 of 152 PIO patients (11.2%; P = not significant, PIO vs PLAC). However, the cumulative incidence of diabetes from start of study medication to end of washout period remained significantly lower in PIO vs PLAC (10.7 vs 22.3%; P < .005). After therapy was discontinued, 23.0% (35/152) of PIO-treated patients remained normal-glucose tolerant (NGT) vs 13.8% (19/138) of PLAC-treated patients (P = .04). Insulin secretion/insulin resistance index (I0–120/G0–120 × Mat...