Efficacy of continuous positive airway pressure (CPAP) preventing type 2 diabetes mellitus in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and insulin resistance: a systematic review and meta-analysis

Background: Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a very common, yet undiagnosed, breathing disorder that has many more implications besides disrupted sleep. Its role as an independent risk factor for metabolic abnormalities such as insulin resistance (IR) and impaired glucose tolerance is becoming increasingly recognized. The main treatment for OSAHS is continuous positive airway pressure (CPAP), however the impact of CPAP on IR and glucose metabolism is still debated. Objectives: Compile all available evidence regarding the effect of CPAP on IR in non-diabetic OSA patients. Methods: A literature search in Medline, Epistemonikos and the Cochrane Controlled Trial Register were searched through March 2018. We included Randomized Controlled Trials (RCTs) comparing CPAP treatment with sham CPAP, placebo or no treatment in non-diabetic adults with OSAHS. Risk of Bias was evaluated using Cochrane tool and a meta-analysis evaluating the efficacy of CPAP in both HOMA index and fasting glucose was done. Certain of evidence was rated using GRADE approach. Results: Nine studies consisting of 443 participants were included. CPAP treatment significantly improved HOMA index (Mean difference = −0.39 Ui (CI, −0.69 to −0.08), p < 0.05. I2 = 57% (GRADE = LOW). However, CPAP showed no significant changes in fasting glucose (GRADE = LOW). Conclusion: This systematic review and meta-analysis shows evidence that metabolic disturbances could be halted and regressed with CPAP treatment in patients with insulin resistance and OSAHS. In conclusion, treatment with CPAP could improve HOMA IR index.