title: Total Weight Loss as the Outcome Measure of Choice After Roux-en-Y Gastric Bypass.
abstract: Currently, there is no agreement on the best method to describe weight loss (WL) after bariatric surgery. The aim of this study is to evaluate short-term outcomes using percent of total body weight loss (%TWL).
  
  
  
  A single-institution retrospective study of 2420 patients undergoing Roux-en-Y gastric bypass (RYGB) was performed. Suboptimal WL was defined as %TWL < 20 % at 12 months.
  
  
  
  Mean preoperative BMI was 46.8 ± 7.8 kg/m(2). One year after surgery, patients lost an average 14.1 kg/m(2) units of body mass index (BMI), 30.0 ± 8.5 %TWL, and 68.5 ± 22.9 %EWL. At 6 and 12 months after RYGB, mean BMI and percent excess WL (%EWL) significantly improved for all baseline BMI groups (p < 0.01, BMI; p = 0.01, %EWL), whereas mean %TWL was not significantly different among baseline BMI groups (p = 0.9). The regression analysis between each metric outcome and preoperative BMI demonstrated that preoperative BMI did not significantly correlate with %TWL at 1 year (r = 0.04, p = 0.3). On the contrary, preoperative BMI was strongly but negatively associated with the %EWL (r = -0.52, p < 0.01) and positively associated with the BMI units lost at 1 year (r = 0.56, p < 0.01). In total, 11.3 % of subjects achieved <20 %TWL at 12 months and were considered as suboptimal WL patients.
  
  
  
  The results of our study confirm that %TWL should be the metric of choice when reporting WL because it is less influenced by preoperative BMI. Eleven percent of patients failed to achieve successful WL during the in the first year after RYGB based on our definition.
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.|Department of Gastrointestinal Surgery, Institute of Digestive and Metabolic Diseases, Fundació Clínic per a la Recerca Biomèdica, Hospital Clinic de Barcelona, Barcelona, Spain.
authors.forename: Ricard
authors.initials: R
authors.lastname: Corcelles
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.
authors.forename: Mena
authors.initials: M
authors.lastname: Boules
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.
authors.forename: Dvir
authors.initials: D
authors.lastname: Froylich
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.
authors.forename: Amani
authors.initials: A
authors.lastname: Hag
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Daigle
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Aminian
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA. BRETHAS@ccf.org.
authors.forename: Stacy A
authors.initials: SA
authors.lastname: Brethauer
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.
authors.forename: Barto
authors.initials: B
authors.lastname: Burguera
authors.affiliation: Bariatric and Metabolic Institute, Cleveland Clinic, 9500 Euclid Avenue, M61, Cleveland, OH, 44195, USA.
authors.forename: Philip R
authors.initials: PR
authors.lastname: Schauer
mesh_terms: D015992:Body Mass Index; D005260:Female; D015390:Gastric Bypass / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000601:surgery*; D009820:Ohio; D017063:Outcome Assessment, Health Care; D012044:Regression Analysis; D012189:Retrospective Studies; D015431:Weight Loss
keywords: Body mass index; Reporting weight loss; Roux-en-Y gastric bypass; Suboptimal weight loss; Total weight loss