Respiratory sleep disturbances in patients undergoing gastric bypass surgery and their relation to metabolic syndrome.

ABSTRACT

BACKGROUND: The prevalence of obstructive sleep apnea syndrome (OSAS) is high in obese patients. Certain components of metabolic syndrome are linked to OSAS, but there is no information on their association in morbidly obese patients. Our aim was to ascertain the prevalence of respiratory disturbances during sleep in candidates for bariatric surgery and to study their association with metabolic syndrome. METHODS: We examined the preoperative records (history, physical examination and laboratory findings, spirometry, and overnight pulse oximetry [arterial oxygen saturation by pulse oximetry, [SpO(2)]]) of patients scheduled for gastric bypass surgery for 1 year in our hospital; an overnight sleep study was performed if SpO(2) readings or symptoms suggested sleep disturbance. Metabolic syndrome was defined according to the criteria of the National Cholesterol Education Program's Adult Treatment Panel III. RESULTS: Of the 31 patients studied, 19 (61.3%) had OSAS, including 15 newly diagnosed cases with a mean +/- standard deviation apnea-hypopnea index of 49 +/- 36. OSAS patients had higher fasting plasma glucose and triglyceride levels and a higher prevalence of diabetes. Metabolic syndrome was also more frequent in subjects with previously untreated OSAS (13/14, 92%) than in those without sleep disturbance (six of 11, 55%; p = 0.033). Conversely, the prevalence of OSAS in patients with metabolic syndrome was higher (13/19, 68%) than in subjects without metabolic syndrome (one of six, 17%; p = 0.026) even though the two groups had similar body mass index. CONCLUSIONS: Sleep disordered breathing is very prevalent in obese patients who are candidates for bariatric surgery and its presence is related to metabolic syndrome.