A Randomized Controlled Trial of Continuous Positive Airway Pressure on Glucose Tolerance in Obese Patients with Obstructive Sleep Apnea

STUDY OBJECTIVE: Obstructive Sleep Apnea (OSA) is associated with an increasedprevalence of metabolic syndrome (MetS), even in patients with morbid obesity. Ourgoal was to address whether continuous positive airway pressure (CPAP) treatmentimproved glucose metabolism in this population.DESIGN: Prospective randomized controlled trialSETTINGS: Sleep clinics of Hospital Universitary de Bellvitge and Hospital de la SantaCreu i Sant Pau, Barcelona Spain.PATIENTS: Severe OSA patients with morbid obesity without diabetes.INTERVENTIONS: Patients received conservative (CT) versus CPAP treatment for 12weeks.MEASUREMENTS: MetS components, homeostasis model assessment of insulinresistance (HOMA-IR) and oral glucose tolerance were assessed at baseline and aftertreatment.RESULTS: A total of 80 patients completed the study (42 CPAP and 38 CT patients).After 12 weeks of CPAP treatment, weight loss was similar in both groups and physicalactivity, prevalence of MetS and HOMA-IR did not change in either group. In the CPAPgroup impaired glucose tolerance (IGT) reversed in 9 patients and none developed IGT,while IGT reversed in 5 patients and 5 developed IGT in the CT group (p=0.039 in theFisher test). Changes in 2 hour plasma glucose after glucose load were greater in theCPAP group than in the CT group (CPAP: -0.5±1.5 vs CT: 0.33±1.9, p=0.007).CONCLUSIONS: The improvement of glucose tolerance in morbidly obese patientswith severe OSA, without changes in HOMA-IR, supports an improvement inperipheral insulin resistance after CPAP treatment.