Study objectives: Weight loss improves obstructive sleep apnea (OSA), and clinicians regularly recommend dieting to their patients with OSA; however, many morbidly obese patients may be unable to lose weight without medical or surgical intervention. Gastric bypass surgery (GB) facilitates weight loss for morbidly obese patients. Studies show GB will improve symptoms associated with OSA, but little is known regarding the long-term effects of GB on this population.
Design: Historical, retrospective, cohort study.
Setting: Sleep Disorders Center, Sentara Norfolk General Hospital, Norfolk, VA.
Participants: A list of subjects who underwent vertical Roux-en-Y GB was cross-referenced with the Sleep Disorders Center at Sentara Norfolk General Hospital to identify patients with a diagnosis of OSA during the preoperative evaluation prior to undergoing GB.
Measurements: Our primary end point was the respiratory disturbance index (RDI). Secondary variables were body mass index (BMI), mean oxygen saturation, low oxygen saturation, a standardized depression scale, and the continuous positive airway pressure (CPAP) requirement.
Results: Thirty-four subjects with a diagnosis of OSA prior to GB were identified. Of these, 28 subjects were located and offered follow-up polysomnography after GB. Eight subjects returned for repeat polysomnography. The subjects were re-evaluated an average of 28 months after GB. Seven subjects had a lower BMI after GB. Mean BMI was reduced by 31% (p = 0.001). The mean decrease in RDI was 75% (p = 0.01), and five of the eight subjects no longer required nasal CPAP. Mean nocturnal oxygen saturation improved from 95 to 97% (p = 0.04).
Conclusions: Weight reduction following GB is associated with significant improvements in sleep apnea indexes an average of 28 months after GB. Re-evaluation after GB is necessary to identify and treat those patients who, despite subjective improvement, may continue to require CPAP for residual OSA.