title: Patterns of Weight Loss Response Following Gastric Bypass and Sleeve Gastrectomy.
abstract: BACKGROUND
  Despite the health benefits of bariatric surgery (BS) extend beyond WL, better understanding of the WL response may help improve the outcomes of BS. In this context, we aimed to assess patterns within the variability of weight loss (WL) after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).
  
  
  METHODS
  WL data from 658 subjects that underwent RYGB (n = 464) or SG (n = 194) as first BS were analyzed. Based on excess WL (EWL), subjects were categorized as good WL responders (EWL ≥ 50 % at nadir weight and throughout follow-up), primarily poor WL responders (1-PWL:EWL < 50 % at nadir weight and thereafter), and secondarily poor WL responders (2-PWL:EWL ≥ 50 % at nadir weight, but <50 % at last follow-up visit). Predictors associated with different WL outcomes were ascertained using regression analysis.
  
  
  RESULTS
  Median follow-up was 55.7 months. Nadir EWL ranged 12.4-143.6 %; last follow-up visit EWL ranged -22.1-143.6 % and weight regain (WR) ranged 0-64.1 kg. Good WL was found in 75.7 of the cohort. 1-PWL response (4.7 %) was characterized by lesser WL but similar WR as compared to good WL and was associated with larger BMI and diabetes prior to surgery. 2-PWL response (19.6 %) was characterized by larger WR as compared to the other groups and was more common following SG. Lesser percentage of medical appointments kept was associated with 1-PWL and 2-PWL.
  
  
  CONCLUSIONS
  Our data show the high inter-individual variability of the WL response at mid-term after RYGB and SG and that poor WL after BS could be illustrated by two different patterns, characterized either by sustained limited WL (1-PWL), or pronounced weight regain (2-PWL).
authors.affiliation: Obesity Unit, Endocrinology and Nutrition Department, Hospital Clinic Universitari, Villarroel 170, 08036, Barcelona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: de Hollanda
authors.forename: Tania
authors.initials: T
authors.lastname: Ruiz
authors.forename: Amanda
authors.initials: A
authors.lastname: Jiménez
authors.forename: Lílliam
authors.initials: L
authors.lastname: Flores
authors.forename: Antonio
authors.initials: A
authors.lastname: Lacy
authors.forename: Josep
authors.initials: J
authors.lastname: Vidal
mesh_terms: D000328:Adult; D005260:Female; D005743:Gastrectomy; D015390:Gastric Bypass; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D015431:Weight Loss / Q000502:physiology*