title: Novel equations to estimate lean body mass in maintenance hemodialysis patients.
abstract: BACKGROUND
  Lean body mass (LBM) is an important nutritional measure representing muscle mass and somatic protein in hemodialysis patients, for whom we developed and tested equations to estimate LBM.
  
  
  METHODS
  A study of diagnostic test accuracy.
  
  
  METHODS
  The development cohort included 118 hemodialysis patients with LBM measured using dual-energy x-ray absorptiometry (DEXA) and near-infrared (NIR) interactance. The validation cohort included 612 additional hemodialysis patients with LBM measured using a portable NIR interactance technique during hemodialysis.
  
  
  METHODS
  3-month averaged serum concentrations of creatinine, albumin, and prealbumin; normalized protein nitrogen appearance; midarm muscle circumference (MAMC); handgrip strength; and subjective global assessment of nutrition.
  
  
  METHODS
  LBM measured using DEXA in the development cohort and NIR interactance in validation cohorts.
  
  
  RESULTS
  In the development cohort, DEXA and NIR interactance correlated strongly (r = 0.94, P < 0.001). DEXA-measured LBM correlated with serum creatinine level, MAMC, and handgrip strength, but not with other nutritional markers. Three regression equations to estimate DEXA-measured LBM were developed based on each of these 3 surrogates and sex, height, weight, and age (and urea reduction ratio for the serum creatinine regression). In the validation cohort, the validity of the equations was tested against the NIR interactance-measured LBM. The equation estimates correlated well with NIR interactance-measured LBM (R² ≥ 0.88), although in higher LBM ranges, they tended to underestimate it. Median (95% confidence interval) differences and interquartile range for differences between equation estimates and NIR interactance-measured LBM were 3.4 (-3.2 to 12.0) and 3.0 (1.1-5.1) kg for serum creatinine and 4.0 (-2.6 to 13.6) and 3.7 (1.3-6.0) kg for MAMC, respectively.
  
  
  CONCLUSIONS
  DEXA measurements were obtained on a nondialysis day, whereas NIR interactance was performed during hemodialysis treatment, with the likelihood of confounding by volume status variations.
  
  
  CONCLUSIONS
  Compared with reference measures of LBM, equations using serum creatinine level, MAMC, or handgrip strength and demographic variables can estimate LBM accurately in long-term hemodialysis patients.
authors.affiliation: Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, CA, USA.
authors.forename: Nazanin
authors.initials: N
authors.lastname: Noori
authors.forename: Csaba P
authors.initials: CP
authors.lastname: Kovesdy
authors.forename: Rachelle
authors.initials: R
authors.lastname: Bross
authors.forename: Martin
authors.initials: M
authors.lastname: Lee
authors.forename: Antigone
authors.initials: A
authors.lastname: Oreopoulos
authors.forename: Deborah
authors.initials: D
authors.lastname: Benner
authors.forename: Rajnish
authors.initials: R
authors.lastname: Mehrotra
authors.forename: Joel D
authors.initials: JD
authors.lastname: Kopple
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kalantar-Zadeh
mesh_terms: D015502:Absorptiometry, Photon; D000886:Anthropometry; D001823:Body Composition; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011228:Prealbumin / Q000032:analysis; D006435:Renal Dialysis; D012709:Serum Albumin / Q000032:analysis; D019265:Spectroscopy, Near-Infrared
chemical_list: D011228:Prealbumin; D012709:Serum Albumin; D003404:Creatinine