VAMONOS (Veterans Affairs' Metabolism, Obstructed and Non-Obstructed Sleep) Study: Effects of CPAP Therapy on Glucose Metabolism in Patients with Obstructive Sleep Apnea.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) and type 2 diabetes mellitus (T2DM) are prevalent disorders that pose increased risk of cardiovascular disease and death. The objective of this study was to clarify if continuous positive airway pressure (CPAP) therapy for OSA affects T2DM control and emergence.

METHODS: Point-of-care, comparative effectiveness study; cross-sectional and longitudinal analyses.

RESULTS: Our cohort included 928 consecutive patients; 13% were women; 36% were Caucasians and 61% African-Americans. OSA was diagnosed in approximately 738 patients and CPAP was initiated in 718 patients; median duration of therapy was 5 mo (25% to 75% interquartile range [IQR] 3-14). Patients with OSA used CPAP therapy for a median duration of 4.8 h, 34.5% of the nights. Adherence to CPAP was prespecified as follows: good (≥ 70% nights and ≥ 4 h/night), excellent (≥ 80% nights and ≥ 6 h/night) or outstanding (≥ 90% of nights and 8 h/night). Based on objective data, good, excellent, and outstanding compliance were found in only 30%, 20%, and 6%, respectively. Three percent of subjects without CPAP follow-up and less than 4% of those nonadherent to CPAP therapy (based on the established criteria) developed incident T2DM. Incident T2DM developed in only 0.8% of those with good compliance and in none (0%) of those in the excellent and outstanding groups. During follow-up, median weight change was +0.3 kg (IQR -1.8 to 2.7).

CONCLUSIONS: We found that an outstanding compliance to CPAP reduced fasting blood glucose in patients with OSA. Longitudinally, higher levels of therapeutic adherence may affect the rate of incident impaired fasting glucose, prediabetes, and T2DM, despite the observed weight gains.

COMMENTARY: A commentary on this article appears in this issue on page 365.