Effects of continuous positive airway pressure treatment on glucose metabolism in patients with obstructive sleep apnea.

A possible association between obstructive sleep apnea (OSA) and type 2 diabetes (T2DM) has been suggested. OSA could alter glucose metabolism, generating insulin resistance and favoring the development of T2DM. In addition, our greater understanding of intermediate disorders produced by intermittent hypoxia and sleep fragmentation, such as sympathetic activation, oxidative stress, systemic inflammation and alterations in appetite-regulating hormones, provides biological plausibility to this possible association. Nevertheless, there are still few data available about the consequences of suppressing apnea. Therefore, the objective of this review was to analyze current knowledge about the effect of continuous positive airway pressure (CPAP) on glucose metabolism. A global interpretation of the studies evaluated shows that CPAP could improve insulin resistance, and perhaps also glycemic control, in OSA patients who still have not developed diabetes. In addition, it seems possible that the effect of CPAP is still greater in patients with OSA and T2DM, particularly in those patients with more severe and symptomatic OSA, in those with poorer baseline glycemic control and with greater compliance and duration of CPAP treatment. In conclusion, although the current information available is limited, it suggests that apnea reversion by means of CPAP could improve the control of glucose metabolism.