title: Modeled urea distribution volume and mortality in the HEMO Study.
abstract: OBJECTIVE
  In the Hemodialysis (HEMO) Study, observed small decreases in achieved equilibrated Kt/V(urea) were noncausally associated with markedly increased mortality. Here we examine the association of mortality with modeled volume (V(m)), the denominator of equilibrated Kt/V(urea).
  
  
  METHODS
  Parameters derived from modeled urea kinetics (including V(m)) and blood pressure (BP) were obtained monthly in 1846 patients. Case mix-adjusted time-dependent Cox regressions were used to relate the relative mortality hazard at each time point to V(m) and to the change in V(m) over the preceding 6 months. Mixed effects models were used to relate V(m) to changes in intradialytic systolic BP and to other factors at each follow-up visit.
  
  
  RESULTS
  Mortality was associated with V(m) and change in V(m) over the preceding 6 months. The association between change in V(m) and mortality was independent of vascular access complications. In contrast, mortality was inversely associated with V calculated from anthropometric measurements (V(ant)). In case mix-adjusted analysis using V(m) as a time-dependent covariate, the association of mortality with V(m) strengthened after statistical adjustment for V(ant). After adjustment for V(ant), higher V(m) was associated with slightly smaller reductions in intradialytic systolic BP and with risk factors for mortality including recent hospitalization and reductions in serum albumin concentration and body weight.
  
  
  CONCLUSIONS
  An increase in V(m) is a marker for illness and mortality risk in hemodialysis patients.
authors.affiliation: University of Illinois at Chicago, Department of Medicine, 820 South Wood Street, Chicago, IL 60612, USA. jtdaugir@uic.edu
authors.forename: John T
authors.initials: JT
authors.lastname: Daugirdas
authors.forename: Tom
authors.initials: T
authors.lastname: Greene
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Depner
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Levin
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Chertow
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism* / Q000401:mortality* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D011788:Quality of Life; D006435:Renal Dialysis / Q000379:methods* / Q000401:mortality*; D020379:Risk Adjustment; D012307:Risk Factors; D014508:Urea / Q000097:blood*
chemical_list: D015415:Biomarkers; D014508:Urea