Impact of Kidney Graft Weight-to-Recipient Body Weight Ratio on Long-Term Graft Function in Living Donor Kidney Transplant.

OBJECTIVES: Our objective was to evaluate the effect of kidney graft weight-to-recipient body weight ratio as a nonimmune factor that may affect long-term graft function.

MATERIALS AND METHODS: We retrospectively collected data from 2531 living donor kidney transplant procedures performed between 1994 and 2010 at Shahid Labbafinejad Medical Center; 635 patients were included in this study. Each kidney was weighed after cold wash. The kidney weight-to-recipient body weight ratio was calculated. As an indicator of graft function, we used the Modification of Diet in Renal Disease Study Group equation to estimate glomerular filtration rate. For statistical analyses, we used simple linear regression analysis and the mixed model test using SPSS version 17.0 software (SPSS, Chicago, IL, USA).

RESULTS: Mean age of recipients and median follow-up duration were 37.5 years (range, 6-77 y) and 36 months (range, 25-84 mo). Long-term graft function showed a positive correlation with kidney graft-to-recipient body weight ratio but not with the graft weight alone. The magnitude of this correlation was higher early after surgery (day 7) and decreased with long-term follow-up but was still statistically significant (P < .001).

CONCLUSIONS: From our results, we conclude that kidney graft-to-recipient body weight ratio is correlated with the kidney graft function; graft size matching may be considered for kidney donor selection.