title: Skinfold anthropometry--the accurate method for fat free mass measurement in COPD.
abstract: OBJECTIVE
  Fat free mass index (FFMI) is an independent predictor of metabolic and functional consequences in COPD. For its measurement dual energy X-ray absorptiometry (DEXA), skin-fold anthropometry (SFA), bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS) are used in clinical practice. The aim of our pilot study was to analyse precisely and critically which method is most accurate and available for common use in clinical practice for measurement of FFM by assessment against relevant DEXA in patients with COPD.
  
  
  METHODS
  This was an observational cross-sectional study of consecutive COPD subjects. FFM by methods of SFA, two versions of BIA, and BIS was compared with that from clinically relevant DEXA in 41 outpatients (mean age 66.5 ± 7.7 yrs) with stable COPD, 34 men and 7 women, with mean BMI 28.2 ± 6.1 kg.m(-2).
  
  
  RESULTS
  All methods underestimate FFM in comparison with DEXA. In the general evaluation non-significant differences with the smallest mean bias were demonstrated for SFA (1.2 kg) and BIA (3.8 kg), but there was a difference of more than 9 kg using BIS and BIA COPD methods (p < 0.0001). The best agreement between DEXA and SFA was demonstrated via Lin's concordance coefficient and Bland-Altman test.
  
  
  CONCLUSIONS
  SFA has been demonstrated as an accurate, available and cheap method for determination of FFM and FM with application of the Durnin Womersley equation for body density and with the Siri equation for FM in patients with COPD. SFA can be easily applied in routine clinical practice.
authors.affiliation: 1Charles University in Prague, Faculty of Pharmacy , Hradec Kralove , Czech Republic.
authors.forename: Miloslav
authors.initials: M
authors.lastname: Hronek
authors.forename: Miroslav
authors.initials: M
authors.lastname: Kovarik
authors.forename: Petra
authors.initials: P
authors.lastname: Aimova
authors.forename: Vladimir
authors.initials: V
authors.lastname: Koblizek
authors.forename: Ladislava
authors.initials: L
authors.lastname: Pavlikova
authors.forename: Frantisek
authors.initials: F
authors.lastname: Salajka
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Zadak
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D001823:Body Composition; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D058266:Dielectric Spectroscopy; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000150:complications / Q000175:diagnosis*; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications; D012885:Skinfold Thickness