RESUMO
BACKGROUND: Obstructive sleep apnea (OSA) is a prevalent condition that is associated with significant comorbidities, including obesity, hypertension, cardiovascular disease, and insulin resistance. Continuous positive airway pressure (CPAP) is an effective treatment for OSA. The effect of CPAP on glucose metabolism in patients with OSA has been controversial. This study evaluates the impact of CPAP on patients with OSA and type 2 diabetes mellitus (T2DM) or prediabetes. MATERIALS AND METHODS: PubMed, Ovid Medline, and EMBASE were searched for original English language studies performed on or after 2003. Subjects were aged > 18 years, were diagnosed with OSA via polysomnography, and had either T2DM or prediabetes according to laboratory evaluation. RESULTS: Of the 22 articles that met the selection criteria, 17 studies (77%) showed that a prolonged use of CPAP produced significant changes in glucose metabolism of patients who had T2DM and prediabetes. These changes were observed in studies measuring glycosylated hemoglobin (HbA1c), postprandial or nocturnal glucose, and insulin sensitivity or resistance. Of the 17 studies, 4 showed improvement in HbA1c levels or increased insulin sensitivity only after long-term use of CPAP for ≥ 3 months. CONCLUSION: This literature review shows that CPAP improves not only hypoxia while restoring normal breathing during sleep, but also glucose metabolism in patients with OSA and T2DM or prediabetes. A few studies have shown that patients can experience even better results with long-term CPAP treatment (≥ 3 months of daily use) for > 4 hours a night. Therefore, this improvement in glucose metabolism with the use of CPAP may contribute to T2DM prevention and decrease further progression of the disease. However, additional studies are needed to confirm these findings.
