Introduction: Obstructive sleep apnoea (OSA) is a prevalent disorder characterised by repetitive upper-airway obstruction during sleep, and it is associated with type 2 diabetes. Continuous positive airway pressure (CPAP) is the primary treatment for OSA. Prior studies investigating whether CPAP can improve insulin resistance or glucose control in OSA patients have resulted in conflicting findings. This meta-analysis investigated whether CPAP treatment could improve glucose metabolism and insulin resistance in patients with OSA and type 2 diabetes.
Material and methods: We performed a systematic literature search using Medline, Cochrane, EMBASE, and Google Scholar databases for randomised controlled prospective studies that investigated the effect of CPAP on glycaemic control or insulin sensitivity in subjects with type 2 diabetes.
Results: The combined standard (STD) paired difference in mean change in the levels of glycated haemoglobin (HbA_1c) was –0.073% (standard error (SE): 0.126), indicating that CPAP treatment did not alter HbA_1c levels. The combined STD paired difference in mean change of insulin sensitivity was observed as 0.552 mmol/kg • min (SE = 0.196) and indicated insulin sensitivity significantly increased with CPAP treatment (p = 0.005).
Conclusions: We found that the CPAP treatment did not alter HbA_1c levels but did significantly improve insulin resistance, indicating treating OSA can positively impact the symptoms of type 2 diabetes.