Continuous Glucose Monitoring Among People with and without Diabetes Mellitus and Sleep Apnoea

The association of sleep apnoea with insulin resistance and type 2 diabetes mellitus (T2DM) is well studied. However, little is known on the impact of sleep apnoea on glycaemic variability (GV). Continuous glucose monitoring (CGM) systems shed light on GV not only during sleep but throughout the day among people with or without diabetes mellitus (DM) and obstructive sleep apnoea syndrome (OSAS). In this narrative review, we aimed to summarise the evidence on the role of CGM in assessing GV among individuals with sleep apnoea. Articles related to CGM use among individuals with OSAS were included. Emerging data suggests a significant impact of OSAS on glucose metabolism during sleep and wakefulness. Of note, OSAS affects GV irrespective of glycaemic status. Moreover, the severity of OSAS has been associated with increased GV. As GV triggers oxidative stress, it contributes to adverse outcomes in people with diabetes and/or OSAS. Interestingly, a beneficial effect of continuous positive airway pressure (CPAP) treatment on blood glucose and on GV in individuals with both T2DM and OSAS has emerged, but evidence is conflicting. Additionally, among pregnant women with gestational diabetes and sleep-disordered breathing, CGM could detect nocturnal hyperglycaemic episodes, improving glycaemic control and perinatal outcomes. Future studies are needed to investigate the exact impact of OSAS treatment on GV.