title: Radiographs and low field MRI (0.2T) as predictors of efficacy in a weight loss trial in obese women with knee osteoarthritis.
abstract: BACKGROUND
  To study the predictive value of baseline radiographs and low-field (0.2T) MRI scans for the symptomatic outcome of clinically significant weight loss in obese patients with knee osteoarthritis.
  
  
  METHODS
  In this study we hypothesize that imaging variables assessed with radiographs and MRI scans pre-treatment can predict the symptomatic changes following a recommended clinically significant weight reduction Patients were recruited from the Department of Rheumatology, Frederiksberg Hospital, Denmark. Eligibility criteria were: age >18 years; primary osteoarthritis according to ACR; BMI > 28 kg/m2; motivation for weight loss. Subjects were randomly assigned to either intervention by low-energy diet (LED) for 8 weeks followed by another 24 weeks of dietary instruction or control-group. MRI scans and radiographs were scored for structural changes and these parameters were examined as independent predictors of changes in osteoarthritis symptoms after 32 weeks. The outcome assessor and statistician were blinded to group allocation.
  
  
  RESULTS
  No significant correlations were found between imaging variables and changes in Western Ontario and McMaster Universities Index of Osteoarthritis (Spearman's test, r < 0.33 and P > 0.07).Only the LED group achieved a weight loss, with a mean difference of 16.3 kg (95%CI: 13.4-19.2;P < 0.0001) compared to the control group. The total WOMAC index showed a significant difference favouring LED, with a group mean difference of - 321.3 mm (95%CI: -577.5 to -65.1 mm; P = 0.01). No significant adverse events were reported.
  
  
  CONCLUSIONS
  Stage of joint destruction, assessed on either radiographs or low-field MRI (0.2T), does not preclude a symptoms relief following a clinically relevant weight loss in elderly obese female patients with knee osteoarthritis.
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Frederiksberg, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Gudbergsen
authors.forename: Mikael
authors.initials: M
authors.lastname: Boesen
authors.forename: Robin
authors.initials: R
authors.lastname: Christensen
authors.forename: Arne
authors.initials: A
authors.lastname: Astrup
authors.forename: Henning
authors.initials: H
authors.lastname: Bliddal
mesh_terms: D000368:Aged; D004038:Diet, Reducing; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy* / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011859:Radiography; D016896:Treatment Outcome; D015431:Weight Loss / Q000502:physiology