title: Red cell distribution width is a novel biomarker that predicts excess body-mass index loss 1 year after laparoscopic Roux-en-Y gastric bypass.
abstract: Bariatric surgery is the most effective method for producing sustained weight loss, improving obesity-associated comorbidities and reducing inflammation in the morbidly obese population. The red cell distribution width (RDW) is a novel marker of inflammation that is usually reported as part of a complete blood count. In this study, we tested our hypothesis that red cell distribution width might represent a novel biomarker predictive of excess body-mass index loss (EBMIL) following laparoscopic Roux-en-Y gastric bypass (LRYGB).
  
  
  
  Five hundred and forty-seven LRYGB patients included from a single institution were individually reviewed, noting both preoperative RDW and percent excess BMI loss at 6 months and 1 year post-LRYGB (%EBMIL180 and %EBMIL365, respectively). Bivariate and multivariate linear regression analysis was conducted between age, gender, initial body-mass index (BMI0) and RDW and each of the two endpoints, to assess the independence of RDW as a predictor of postoperative success.
  
  
  
  The median RDW was 13.9 (13.3-14.6) %, and median EBMIL180 and EBMIL365 were 55.4 (45.2-66.7) % and 71.3 (58.9-87.8) %, respectively. After controlling for age, gender and BMI0, RDW was associated with %EBMIL365 (B = -1.4 [-2.8 to -0.002] %, P = .05), but not %EBMIL180 (B = -0.6 [-1.6 to 0.5] %, P = .30. Upon Kruskal-Wallis analysis, patients with a preoperative RDW > 15.0 % had significantly lower %EBMIL than those in the <13.0 % (P < .001) and 13.0-15.0 % (P < .01) strata.
  
  
  
  RDW is predictive of EBMIL at 1 year following LRYGB. This represents a novel preoperative biomarker that may provide clinically useful prognostic information.
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, 1161 21st Ave S, MCN T2121, Nashville, TN, 37232-2730, USA. eric.s.wise@vanderbilt.edu.|Department of Surgery, University of Maryland Medical Center, Baltimore, MD, USA. eric.s.wise@vanderbilt.edu.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Wise
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, 1161 21st Ave S, MCN T2121, Nashville, TN, 37232-2730, USA.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Hocking
authors.affiliation: Department of Surgery, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Weltz
authors.affiliation: Department of Surgery, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Uebele
authors.affiliation: Department of Surgery, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Jose J
authors.initials: JJ
authors.lastname: Diaz
authors.affiliation: Department of Surgery, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Kavic
authors.affiliation: Department of Surgery, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Kligman
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D015415:Biomarkers / Q000097:blood; D004909:Erythrocyte Indices; D005260:Female; D015390:Gastric Bypass / Q000379:methods*; D006801:Humans; D010535:Laparoscopy / Q000379:methods; D016018:Least-Squares Analysis; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009767:Obesity, Morbid / Q000097:blood / Q000601:surgery*; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D015431:Weight Loss
chemical_list: D015415:Biomarkers
keywords: Bariatrics; Biomarkers; Gastric bypass; Laparoscopy; Outcomes