title: Centralized assessment of dual-energy X-ray absorptiometry (DEXA) in multicenter studies of HIV-associated lipodystrophy.
abstract: BACKGROUND
  The accurate measurement of total body and subcutaneous fat is essential if therapeutic interventions, aimed at preventing or reversing lipodystrophy syndrome, are to be adequately assessed. The aim of this study was to investigate the variability of dual-energy X-ray absorptiometry (DEXA) scans analysis performed at local sites compared to central analysis in a multicenter clinical trial.
  
  
  METHODS
  The PIILR study was a multicenter randomized clinical trial in which 80 HIV-infected patients with physician-documented lipodystrophy had serial measurements of body composition performed with Lunar DEXA scans. Scans were analyzed at local sites and then were reanalyzed centrally.
  
  
  RESULTS
  DEXA scans from 73 patients who completed 24 weeks study were compared. Greater variation in the locally analyzed results than in the centrally reanalyzed data was noted, with arm, leg, and combined limb fat being most divergent between the local and centralized assessments (ratio of local to central standard deviation was 1.28, 1.31, and 1.35, respectively). The magnitude of this variance was enough to alter statistically relevant differences between study populations.
  
  
  CONCLUSIONS
  Quality assurance is an important issue in the use of DEXA scans to determine body fat composition in multicenter research studies. A central quality assurance site should be incorporated to reduce variability in results.
authors.affiliation: National Centre for HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, Australia. dsmith@nchecr.unsw.edu.au
authors.forename: Don E
authors.initials: DE
authors.lastname: Smith
authors.forename: Jeff
authors.initials: J
authors.lastname: Hudson
authors.forename: Allison
authors.initials: A
authors.lastname: Martin
authors.forename: Judith
authors.initials: J
authors.lastname: Freund
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Griffiths
authors.forename: Sue
authors.initials: S
authors.lastname: Kalnins
authors.forename: Matthew
authors.initials: M
authors.lastname: Law
authors.forename: Andrew
authors.initials: A
authors.lastname: Carr
authors.forename: David A
authors.initials: DA
authors.lastname: Cooper
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D001823:Body Composition; D005260:Female; D015658:HIV Infections / Q000150:complications*; D039682:HIV-Associated Lipodystrophy Syndrome / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results