title: Long-term impact of donor-recipient size mismatching in deceased donor kidney transplantation and in expanded criteria donor recipients.
abstract: BACKGROUND
  The degree to which recipient/donor (R/D) size mismatching leads to nephron underdosing and worse kidney allograft survival remains poorly defined, particularly in the setting of preexisting nephron loss such as the expanded criteria donor (ECD).
  
  
  METHODS
  We performed a retrospective analysis of 69,737 deceased donor transplants followed by a subset analysis of ECD transplants using data from the Scientific Registry of Transplant Recipients from 1992 to 2005. Ratios of R/D body surface area (BSA) were used to estimate nephron disparity and segregate pairs.
  
  
  RESULTS
  In the entire cohort, severe BSA disparity (R/D BSA>1.38 m) was associated with slightly worse 10-year unadjusted graft survival (35% for severe BSA disparity vs. 39% in pairs of comparable size, P<0.0001). In multivariate analysis, BSA disparity was associated with a 15% increased risk of graft loss (hazard ratio 1.15, P<0.0001). Within ECD cohorts, severe BSA disparity was associated with a decrease in 10-year unadjusted graft survival of greater magnitude than the overall cohort (10% for severe BSA disparity vs. 22% in pairs of comparable size, P<0.0004). On multivariate analysis, severe R/D BSA disparity was associated with worse allograft survival similar to the entire cohort (hazard ratio 1.18, P=0.04).
  
  
  CONCLUSIONS
  Recipients receiving kidneys from substantially smaller donors have a statistically higher rate of graft loss that is more pronounced in ECD kidneys. Although severe R/D size disparity is an independent risk factor for graft loss, the magnitude of this risk requires consideration in the context of other risk factors for the graft loss and the hazards of dialysis.
authors.affiliation: University of Colorado Health Sciences Center, Aurora, CO, USA.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Goldberg
authors.forename: Gerard
authors.initials: G
authors.lastname: Smits
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Wiseman
mesh_terms: D001830:Body Surface Area; D002102:Cadaver; D051799:Delayed Graft Function / Q000453:epidemiology; D005500:Follow-Up Studies; D006085:Graft Survival / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000033:anatomy & histology*; D016030:Kidney Transplantation / Q000401:mortality / Q000502:physiology*; D019520:Living Donors; D015999:Multivariate Analysis; D009929:Organ Size; D018579:Patient Selection; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D014019:Tissue Donors / Q000706:statistics & numerical data*; D016896:Treatment Outcome