title: Trends in Weight Regain Following Roux-en-Y Gastric Bypass (RYGB) Bariatric Surgery.
abstract: BACKGROUND
  The primary purpose of this study was to assess weight loss and occurrence of weight regain among patients who underwent Roux-en-Y gastric bypass (RYGB) using categorical analysis.
  
  
  METHODS
  Study participants were selected from patients who underwent RYGB from a single institution. Participants (n = 300, mean procedure age = 45.6 ± 9.9) completed surveys for self-reported preoperative weight, current weight, and subsequent weights over postoperative years. Measured weights and confirmed procedure dates were acquired from patient medical records. Mean preoperative weight and BMI were 140.8 kg ± 32.1 and 49.7 ± 9.9, respectively, and mean years since surgery was 6.9 ± 4.9. Study subjects were mostly Caucasian (56.7 %) and female (80.3 %). Participants were stratified a priori into four cohorts based on percent of weight loss at 1 year, <25 % (n = 39), 25-30 % (n = 51), 30-35 % (n = 73), and >35 % (n = 113). General linear model analyses were conducted to assess the effect of year one weight loss on percent weight regain.
  
  
  RESULTS
  The mean weight regain for all patients was 23.4 % of maximum weight loss. Using categorical analysis, mean weight regain in the <25, 25-30, 30-35, and >35 % weight loss cohorts was 29.1, 21.9, 20.9, and 23.8 %, respectively. Excessive weight regain, defined as ≥25 % of total lost weight, occurred in 37 % of patients.
  
  
  CONCLUSIONS
  Weight gain is a common complication following RYGB surgery. Despite the percentage of weight loss over the first year, all cohort patient groups regained on average between 21 and 29 % of lost weight. Excessive weight gain was experienced by over one third of patients. Greater initial absolute weight loss leads to more successful long-term weight outcomes.
authors.affiliation: Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL, 60611, USA, tcooper88@gmail.com.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Cooper
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Simmons
authors.forename: Kirsten
authors.initials: K
authors.lastname: Webb
authors.forename: James L
authors.initials: JL
authors.lastname: Burns
authors.forename: Robert F
authors.initials: RF
authors.lastname: Kushner
mesh_terms: D000328:Adult; D000368:Aged; D050110:Bariatric Surgery / Q000379:methods / Q000639:trends*; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000379:methods / Q000639:trends*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000453:epidemiology / Q000601:surgery*; D011184:Postoperative Period; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D015430:Weight Gain; D055815:Young Adult