Prediabetes and Obstructive Sleep Apnea: A review of the pathophysiological interaction and the role of CPAP

Prediabetes is a silent, common, and increasingly prevalent condition that carries a high risk of progressing to type 2 diabetes mellitus (T2DM). Obstructive sleep apnea (OSA) and prediabetes have been proposed to have a bidirectional relationship. We conducted a thorough literature search on PubMed, MEDLINE, Scopus, and Google Scholar using the keywords 'prediabetes,' 'impaired glucose tolerance,' 'OSA,' and 'sleep disordered breathing.' This narrative review aims to synthesize the epidemiology, connections, and mechanisms underlying the interaction between prediabetes and OSA. Patients with OSA experience intermittent hypoxia (IH) and sleep fragmentation due to upper airway collapse. This can lead to sympathetic nervous system activation, systemic inflammation, and changes in metabolic risk factors. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA, providing symptomatic relief and potentially improving related conditions. We present a summary of evidence indicating that treating OSA may potentially enhance glucose metabolism and insulin sensitivity. Furthermore, CPAP therapy may improve parameters of glucose metabolism, but evidence that it slows progression from prediabetes to T2DM remains limited.