The effect of continuous positive airway pressure therapy on glycemic management in individuals with type 2 diabetes (T2D) and obstructive sleep apnea (OSA)

Introduction: Type 2 diabetes (T2D) and obstructive sleep apnea (OSA) are two interrelated epidemics that have significant rates of morbidity and prevalence. According to epidemiologic and clinical research, most people with type 2 diabetes also have OSA, and if left untreated, OSA causes poor glycemic control, which speeds up the development of complications from diabetes. The main objective of the study was to evaluate the impact of treating OSA on hemoglobin A1c (HbA1c) and presenting symptoms, as well as the prevalence and severity of OSA in patients with type 2 diabetes. Material and methods: For this investigation, participants with T2D suspected of OSA who had polysomnography (PSG) performed between January and September 2023 were enrolled. Before PSG, each subject provided written informed consent. After starting CPAP therapy, the HbA1c test was performed again three, six, and twelve months later. Data analysis was conducted using SPSS 11.0 (SPSS Inc., Chicago, IL, USA). Results: 59 (95.2%) of the present 62 diabetic individuals exhibited abnormal PSG. Three patients (5.1%) had mild OSA, 28 (47.5%) had moderate OSA, and 28 (47.5%) had severe OSA based on their Apnea-Hypopnea Index (AHI) score. Individuals with diabetes had a substantially higher mean AHI (25.7 vs. 19.7; p = 0.001) than individuals without diabetes. The mean postprandial (PP) blood glucose was 254.47 mg/dL at 12 weeks and 212.93 mg/dL at 24 weeks, while the mean fasting blood glucose in the diabetic group was 154.47 mg/dL at 12 weeks and 112.93 mg/dL at 24 weeks. There was a statistically significant decrease in the mean HbA1c, which was 8.9% at 12 weeks and 8.3% at 24 weeks (p = 0.0301). Age, gender, body mass index (BMI), hypertension, diabetes, and cardiovascular disease were among the variables that showed a significant correlation with the presence of OSA (P < 0.05); however, only BMI, hypertension, and nocturia showed a relationship with OSA on logistic regression. Overall, continuous positive airway pressure (CPAP) treatment improved the glycemic control of 59% of diabetes patients as indicated by their HbA1c. Patients in the significant, moderate, and modest therapeutic response groups were found in 7%, 20%, and 32% of cases, respectively. Conclusions: Many patients who use CPAP for OSA see a considerable decrease in their HbA1c, which significantly improves blood pressure metrics. Regardless of its impact on HbA1c, CPAP treatment significantly improved blood pressure and sleep ratings, hence promoting its use in patients with OSA and T2DM. CPAP treatment for OSA lowers HbA1c in a sizable portion of diabetics.