title: Validation of clinic weights from electronic health records against standardized weight measurements in weight loss trials.
abstract: To validate clinic weights in electronic health records against researcher-measured weights for outcome assessment in weight loss trials.
  
  
  
  Clinic and researcher-measured weights from a published trial (BE WELL) were compared using Lin's concordance correlation coefficient, Bland and Altman's limits of agreement, and polynomial regression model. Changes in clinic and researcher-measured weights in BE WELL and another trial, E-LITE, were analyzed using growth curve modeling.
  
  
  
  Among BE WELL (n = 330) and E-LITE (n = 241) participants, 96% and 90% had clinic weights (mean [SD] of 5.8 [6.1] and 3.7 [3.9] records) over 12 and 15 months of follow-up, respectively. The concordance correlation coefficient was 0.99, and limits of agreement plots showed no pattern between or within treatment groups, suggesting overall good agreement between researcher-measured and nearest-in-time clinic weights up to 3 months. The 95% confidence intervals for predicted percent differences fell within ±3% for clinic weights within 3 months of the researcher-measured weights. Furthermore, the growth curve slopes for clinic and researcher-measured weights by treatment group did not differ significantly, suggesting similar inferences about treatment effects over time, in both trials.
  
  
  
  Compared with researcher-measured weights, close-in-time clinic weights showed high agreement and inference validity. Clinic weights could be a valid pragmatic outcome measure in weight loss studies.
authors.affiliation: Research Institute, Palo Alto Medical Foundation, Palo Alto, California, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Research Institute, Palo Alto Medical Foundation, Palo Alto, California, USA.
authors.forename: Nan
authors.initials: N
authors.lastname: Lv
authors.affiliation: Research Institute, Palo Alto Medical Foundation, Palo Alto, California, USA.|Department of Medicine, School of Medicine, Stanford University, Stanford, California, USA.
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Rosas
authors.affiliation: Division of Pulmonary and Critical Care Medicine, VA Puget Sound Health Care System, HSR&D, University of Washington, Seattle, Washington, USA.
authors.forename: David
authors.initials: D
authors.lastname: Au
authors.affiliation: Research Institute, Palo Alto Medical Foundation, Palo Alto, California, USA.|Department of Health Policy and Administration, School of Public Health, and Division of Academic Internal Medicine and Geriatrics, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
mesh_terms: D000328:Adult; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D012107:Research Design; D015431:Weight Loss / Q000502:physiology*