title: A mathematical model comparing solute kinetics in low- and high-BMI hemodialysis patients.
abstract: BACKGROUND
  Patients with low Body Mass Index (BMI) on maintenance hemodialysis have a higher mortality risk than patients with elevated BMI. We investigated the use of kinetic modeling to test different hypotheses which have been advanced to explain this relationship.
  
  
  METHODS
  Equations from a three-pool urea-kinetic mathematical model (hepatic mass, extracellular fluid, muscle mass and adipose tissue) were solved to yield predictive profiles of solute and putative toxin concentrations versus time for patients of different body weights.
  
  
  RESULTS
  For the interdialytic interval, our mathematic model suggests that extracellular solute/toxin concentration increases more rapidly in small patients. Additionally, time average concentration (TAC) is higher for this cohort. A lower value of the muscle mass and adipose tissue mass-transfer coefficient (K(MMAT)), which determines the rate of solute release into the extracellular fluid, exacerbates this difference.
  
  
  CONCLUSIONS
  These results suggest that higher mortality for smaller dialysis patients may be mediated by higher time average toxin concentration, especially for solutes with a low mass-transfer coefficient value.
authors: Brown University, Providence, Rhode Island, USA. DCronin-Fine@imshealth.com
authors: D
authors: D
authors: Cronin-Fine
authors: F
authors: F
authors: Gotch
authors: N W
authors: NW
authors: Levin
authors: P
authors: P
authors: Kotanko
authors: M
authors: M
authors: Lysaght
mesh_terms: D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000401:mortality*; D003198:Computer Simulation; D006801:Humans; D007700:Kinetics; D008962:Models, Theoretical; D006435:Renal Dialysis