title: Preoperative predictors of weight loss following bariatric surgery: systematic review.
abstract: BACKGROUND
  Obesity affects 32% of adults in the USA. Surgery generates substantial weight loss, but 20-30% fails to achieve successful weight loss. Our objective was to identify preoperative psychosocial factors associated with weight loss following bariatric surgery.
  
  
  METHODS
  We performed a literature search of PubMed® and the Cochrane Database of Reviews of Effectiveness between 1988 and April 2010. Articles were screened for bariatric surgery and weight loss if they included a preoperative predictor of weight loss: body mass index (BMI), preoperative weight loss, eating disorders, or psychiatric disorder/substance abuse. One thousand seven titles were reviewed, 534 articles screened, and 115 included in the review.
  
  
  RESULTS
  Factors that may be positively associated with weight loss after surgery include mandatory preoperative weight loss (7 of 14 studies with positive association). Factors that may be negatively associated with weight loss include preoperative BMI (37 out of 62 studies with negative association), super-obesity (24 out of 33 studies), and personality disorders (7 out of 14 studies). Meta-analysis revealed a decrease of 10.1% excess weight loss (EWL) for super-obese patients (95% confidence interval (CI) [3.7-16.5%]), though there was significant heterogeneity in the meta-analysis, and an increase of 5.9% EWL for patients with binge eating at 12 months after surgery (95% CI [1.9-9.8%]).
  
  
  CONCLUSIONS
  Further studies are necessary to investigate whether preoperative factors can predict a clinically meaningful difference in weight loss after bariatric surgery. The identification of predictive factors may improve patient selection and help develop interventions targeting specific needs of patients.
authors.affiliation: Department of Surgery, David Geffen School of Medicine at UCLA, 10833 LeConte Ave, 72-215 CHS, Los Angeles, CA 90095, USA. mlivhits@mednet.ucla.edu
authors.forename: Masha
authors.initials: M
authors.lastname: Livhits
authors.forename: Cheryl
authors.initials: C
authors.lastname: Mercado
authors.forename: Irina
authors.initials: I
authors.lastname: Yermilov
authors.forename: Janak A
authors.initials: JA
authors.lastname: Parikh
authors.forename: Erik
authors.initials: E
authors.lastname: Dutson
authors.forename: Amir
authors.initials: A
authors.lastname: Mehran
authors.forename: Clifford Y
authors.initials: CY
authors.lastname: Ko
authors.forename: Melinda Maggard
authors.initials: MM
authors.lastname: Gibbons
mesh_terms: D050110:Bariatric Surgery / Q000523:psychology / Q000706:statistics & numerical data; D015992:Body Mass Index; D001068:Feeding and Eating Disorders / Q000150:complications / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000453:epidemiology / Q000523:psychology* / Q000601:surgery*; D017060:Patient Satisfaction; D010554:Personality Disorders / Q000150:complications / Q000453:epidemiology; D011237:Predictive Value of Tests; D057234:Preoperative Period; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000150:complications / Q000453:epidemiology; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D015431:Weight Loss