title: Isolated Effects of Renal Failure, Anthropometric Indices, and Serum Total Iron-Binding Capacity as Determinants of Muscle Performance in Hemodialysis Patients.
abstract: We quantified the isolated impact of end-stage renal disease (ESRD) on physical performance under contemporary hemodialysis treatment independent of comorbid diseases, characterized principal anthropometric components, and adjusted for their influence and compared associations of C-reactive protein (CRP), albumin, and serum total iron-binding capacity (TIBC) with muscle function.
  
  
  
  A case-control cross-sectional study.
  
  
  
  University medical hospital and outpatient hemodialysis units.
  
  
  
  Ninety prevalent hemodialysis patients without important comorbidities and 140 controls.
  
  
  
  Handgrip strength (HGS) and 10-repetition sit-to-stand time (STS-10).
  
  
  
  Principal component analysis revealed 3 representative anthropometric measures to be included in explanatory models of muscle performance additional to body height: lean body mass, fat mass, and joint size. Controlling for these covariates, age, sex, and residual comorbidity, ESRD was associated with a modest 7.5% reduction in HGS (B = -2.57 kg; 95% confidence interval: -4.81 to -0.39; P = .005; model R(2) 0.74) and a relatively larger prolongation of 27% in STS-10 time (B = 4s; 95% confidence interval: 2.61 to 5.4; P < .001; model R(2) 0.53). Lean body mass and height significantly predicted both tests, fat mass, and wrist size predicted HGS. In the subgroup of dialysis patients, only TIBC showed a significant association with HGS independently from age, sex, wrist size, whereas CRP and albumin did not. STS-10 time was not associated with any of these biomarkers. Results remained stable in sensitivity analyses excluding patients with reported chronic regional motor difficulties and aches.
  
  
  
  ESRD with contemporary hemodialysis therapy has a relatively modest negative comorbidity-free association with HGS and a larger effect on STS-10 lower extremity performance. Nonmodifiable anthropometric indices (body height and for HGS wrist size) have a significant independent impact and should be consistently adjusted for in future studies. In low-comorbidity dialysis patients, TIBC is a superior predictor of HGS compared with albumin and CRP.
authors.affiliation: Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Maja
authors.initials: M
authors.lastname: Bučar Pajek
authors.affiliation: Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Svilan
authors.affiliation: Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Tjaša
authors.initials: T
authors.lastname: Vivoda
authors.affiliation: Department of Nephrology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
authors.forename: Andrej
authors.initials: A
authors.lastname: Škoberne
authors.affiliation: Department of Nephrology, University Medical Centre Ljubljana, Ljubljana, Slovenia. Electronic address: Jernej.pajek@mf.uni-lj.si.
authors.forename: Jernej
authors.initials: J
authors.lastname: Pajek
mesh_terms: D050154:Adiposity; D000328:Adult; D000368:Aged; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D001827:Body Height; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D018737:Hand Strength; D006801:Humans; D007501:Iron / Q000097:blood*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D025341:Principal Component Analysis; D006435:Renal Dialysis; D051437:Renal Insufficiency / Q000097:blood* / Q000175:diagnosis; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000378:metabolism; D014953:Wrist
chemical_list: D015415:Biomarkers; D012709:Serum Albumin; D002097:C-Reactive Protein; D007501:Iron