Does enhanced insulin sensitivity improve sleep measures in patients with obstructive sleep apnea: a randomized, placebo-controlled pilot study

Abstract Background High fasting insulin levels have been reported to predict development of observed apneas, suggesting that insulin resistance may contribute to the pathogenesis of obstructive sleep apnea (OSA). The aim of this study was to determine whether enhancing insulin sensitivity in individuals with OSA would improve sleep measures. Patients/Methods Insulin-resistant, nondiabetic individuals with untreated OSA were randomized (2:1) to pioglitazone (45 mg/day) or placebo for eight weeks in this single-blind study. All individuals had repeat measurements pertaining to sleep (overnight polysomnography and functional outcomes of sleep questionnaire) and insulin action (insulin suppression test). Results A total of 45 overweight/obese men and women with moderate/severe OSA were randomized to pioglitazone ( n  = 30) or placebo ( n  = 15). Although insulin sensitivity increased 31% among pioglitazone-treated compared with no change among individuals receiving placebo ( p  0.001 for between-group difference), no improvement in quantitative or qualitative sleep measurements was observed. Conclusions Pioglitazone administration increased insulin sensitivity in otherwise untreated individuals with OSA, without any change in polysomnographic sleep measures over an eight-week period. These findings do not support a causal role for insulin resistance in the pathogenesis of OSA.