title: Predictive Factors for Insufficient Weight Loss After Bariatric Surgery: Does Obstructive Sleep Apnea Influence Weight Loss?
abstract: BACKGROUND
  Important endpoints of bariatric surgery are weight loss and improvement of comorbidities, of which obstructive sleep apnea (OSA) is the highest accompanying comorbidity (70%). This study aimed to evaluate the influence of OSA on weight loss after bariatric surgery and to provide predictive factors for insufficient weight loss (defined as ≤50% excess weight loss (EWL)) at 1 year follow-up.
  
  
  METHODS
  All consecutive patients, who underwent primary laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy between 2006 and 2014 were retrospectively reviewed. Patients with data on preoperative apnea-hypopnea index (AHI) and pre- and postoperative body mass index (BMI) were included. After surgery, the percentage excess weight loss (%EWL) and BMI changes were compared between preoperatively diagnosed OSA-, subdivided in mild, moderate, and severe OSA, and non-OSA patients. Multivariable logistic regression analysis evaluated predictive factors for ≤50% EWL.
  
  
  RESULTS
  A total of 816 patients, 522 (64%) with and 294 (36%) without OSA, were included. After 1 year, OSA patients achieved less %EWL than non-OSA patients (65.5 SD 20.7 versus 70.3 SD 21.0; p < 0.01). The lowest %EWL was seen in severe OSA patients (61.7 SD 20.2). However, when adjusted for waist circumference, BMI, and age, no effect of OSA was seen on %EWL or changes in BMI. Although AHI, gender, age, BMI, type of surgery, and type II diabetes were predictive factors for ≤50% EWL (area under the curve 0.778), the AHI as variable was of little importance.
  
  
  CONCLUSIONS
  The presence of OSA does not individually impair weight loss after bariatric surgery.
authors.affiliation: Department of Surgery, Sint Lucas Andreas Hospital, Amsterdam, The Netherlands. c.deraaff@slaz.nl.
authors.forename: Christel A L
authors.initials: CA
authors.lastname: de Raaff
authors.affiliation: Department of Surgery, Sint Lucas Andreas Hospital, Amsterdam, The Netherlands.
authors.forename: Usha K
authors.initials: UK
authors.lastname: Coblijn
authors.affiliation: Department of Otolaryngology, Sint Lucas Andreas Hospital, Amsterdam, The Netherlands.|Department of Otolaryngology, University of Antwerp, Antwerp, Belgium.
authors.forename: Nico
authors.initials: N
authors.lastname: de Vries
authors.affiliation: Department of Epidemiology and Biostatistics, VU Medical Center, Amsterdam, The Netherlands.|Department of Methodology and Applied Biostatistics, Faculty of Health and Life Sciences, VU Amsterdam, Amsterdam, The Netherlands.
authors.forename: Martijn W
authors.initials: MW
authors.lastname: Heymans
authors.affiliation: Department of Pulmonology, Sint Lucas Andreas Hospital, Amsterdam, The Netherlands.
authors.forename: Bob T J
authors.initials: BT
authors.lastname: van den Berg
authors.affiliation: Department of Surgery, Sint Lucas Andreas Hospital, Amsterdam, The Netherlands.
authors.forename: Willem F
authors.initials: WF
authors.lastname: van Tets
authors.affiliation: Department of Surgery, Sint Lucas Andreas Hospital, Amsterdam, The Netherlands.
authors.forename: Bart A
authors.initials: BA
authors.lastname: van Wagensveld
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D015897:Comorbidity; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery*; D017286:Polysomnography; D011184:Postoperative Period; D011379:Prognosis; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000453:epidemiology; D017211:Treatment Failure; D015431:Weight Loss
keywords: Bariatric surgery; Continuous positive airway pressure; Excess weight loss; Obstructive sleep apnea