title: Objective evidence that bariatric surgery improves obesity-related obstructive sleep apnea.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is associated with obesity. Our aim in this study is to report objective improvement of obesity-related OSA and sleep quality after bariatric surgery.
  
  
  METHODS
  Prospective bariatric patients were referred for polysomnography if they scored >or=6 on the Epworth Sleepiness Scale. The severity of OSA was categorized by the respiratory disturbance index (RDI) as follows: absent, 0 to 5; mild, 6 to 20; moderate, 21 to 40; and severe, <40. Patients were referred for repeat polysomnography 6 to 12 months after bariatric surgery or when weight loss exceeded 75 lbs. Means were compared using paired t tests. Chi-square tests and linear regression models were used to assess associations between clinical parameters and RDI; P<.05 was considered statistically significant.
  
  
  RESULTS
  Of 349 patients referred for polysomnography, 289 patients had severe (33%), moderate (18%), and mild (32%) OSA; 17% had no OSA. At a median of 11 months (6 to 42 months) after bariatric surgery, mean body mass index (BMI) was 38 +/- 1 kg/m2 (P<.01 vs 56 +/- 1 kg/m2 preoperatively) and the mean RDI decreased to 15 +/- 2 (P<.01 vs 51 +/- 4 preoperatively) in 101 patients who underwent postoperative polysomnography. In addition, minimum oxygen saturation, sleep efficiency, and rapid eye movement latency improved, and the requirement for continuous positive airway pressure was reduced (P<or=.025). Male gender and increasing BMI correlated with increasing RDI (P<.01) by chi-square analysis. In a multivariate linear regression model adjusted for age and gender, preoperative BMI correlated with preoperative RDI (r=0.27; P<.01).
  
  
  CONCLUSIONS
  OSA is prevalent in at least 45% of bariatric surgery patients. Preoperative BMI correlates with the severity of OSA. Surgically induced weight loss significantly improves obesity-related OSA and parameters of sleep quality.
authors.affiliation: Department of Surgery, Interdisciplinary Obesity Group, University of South Florida, Health Sciences Center, Tampa, FL 33601, USA.
authors.forename: Krista L
authors.initials: KL
authors.lastname: Haines
authors.forename: Lana G
authors.initials: LG
authors.lastname: Nelson
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Gonzalez
authors.forename: Tracy
authors.initials: T
authors.lastname: Torrella
authors.forename: Taylor
authors.initials: T
authors.lastname: Martin
authors.forename: Ali
authors.initials: A
authors.lastname: Kandil
authors.forename: Robert
authors.initials: R
authors.lastname: Dragotti
authors.forename: William M
authors.initials: WM
authors.lastname: Anderson
authors.forename: Scott F
authors.initials: SF
authors.lastname: Gallagher
authors.forename: Michel M
authors.initials: MM
authors.lastname: Murr
mesh_terms: D050110:Bariatric Surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D009765:Obesity / Q000453:epidemiology* / Q000601:surgery*; D010045:Outpatients; D017286:Polysomnography; D011182:Postoperative Care; D011237:Predictive Value of Tests; D011300:Preoperative Care; D015995:Prevalence; D011446:Prospective Studies; D012720:Severity of Illness Index; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery*; D016896:Treatment Outcome