Parental donors in live-donor kidney transplantation associated with increased rejection rates and reduced glomerular filtration rates

BACKGROUND. Living unrelated and related kidney transplantation has been shown to have similar allograft survival. However, the effect of donor-recipient relatedness in living-related and unrelated kidney transplantation on graft and patient survival remains uncertain. METHODS. Using Australia and New Zealand Dialysis and Transplant Registry, primary living renal transplant recipients in Australia between 1995 and 2004 were studied (n=1989). Donors were categorized according to their relationship with recipients: parent (n=606), child (n=103), spouse (n=358), sibling (n=656), other living-related donors (n=81), and other living-unrelated donors (n=185). Outcomes analyzed included the presence of rejection at 6 months, estimated glomerular filtration rate (eGFR) at 1 and 3 years, graft survival, and patient survival. RESULTS. A greater proportion of renal transplant recipients from parental and spousal donors were transplanted preemptively. Donor groups had no relationship with graft or patient survival. Parental donors were associated with an increased relative odds of acute rejection (odds ratio 1.69, 95% confidence interval 1.13-2.53, P=0.009) and a lower eGFR at both 1 and 3 years (coefficient -2.99 and -5.68, respectively; P<0.0001) compared to other donor groups (reference sibling donor group). CONCLUSIONS. This study has established that donor-recipient relatedness in both related and unrelated living kidney transplantation had no significant effect on graft and patient survival. Parental donors were associated with a higher relative risk of rejection and lower eGFR in the transplant recipients, although these findings did not translate to a worse graft outcome.