The impact of effective continuous positive airway pressure on homeostasis model assessment insulin resistance in non-diabetic patients with moderate to severe obstructive sleep apnea

Previous studies on the effects of continuous positive airway pressure (CPAP) on homeostasis model assessment insulin resistance (HOMA-IR) in obstructive sleep apnea patients have yielded conflicting results. Therefore, we conducted this meta-analysis to evaluate the impact of effective CPAP on HOMA-IR in non-diabetic patients with moderate to severe obstructive sleep apnea. We searched PubMed, HighWire Press, Ovid Medline (R), Cochrane library and EMBASE before December 2011 on original English language studies. The data on HOMA-IR and body mass index (BMI) were extracted from these studies. As compared with baseline values, 8 to 24 weeks of effective CPAP (>4 h/night) treatment significantly reduced HOMA-IR by an average of 0.75(95% CI, from -0.96 to -0.53; p < 0.001). However, in subjects with irregular CPAP (<4 h/night), this effect was not observed (-0.22; 95%CI, from -2.24 to 1.80; p = 0.83). There were no intervention-related changes in BMI in both regular and irregular CPAP. Our analysis showed that 8 to 24 weeks of effective CPAP could significantly improve HOMA-IR in non-diabetic patients with moderate to severe obstructive sleep apnea, while no significant changes in BMI were detected. Further large scale, randomized and controlled trials are needed to evaluate the longer treatment and its possible effects on weight control and cardiovascular disease.