The association of living donor source with patient and graft survival among kidney transplant recipients in the ERA-EDTA Registry.

In this study we aimed to compare patient and graft survival of kidney transplant recipients who received a kidney from a living-related donor (LRD) or living-unrelated donor (LUD). Adult patients in the ERA-EDTA Registry who received their first kidney transplant in 1998-2017 were included. Ten-year patient and graft survival were compared between LRD and LUD transplants using Cox regression analysis. In total, 14 370 patients received a kidney from a living donor. Of those, 9212 (64.1%) grafts were from a LRD, 5063 (35.2%) from a LUD and for 95 (0.7%), the donor type was unknown. Unadjusted five-year risks of death and graft failure (including death as event) were lower for LRD transplants than for LUD grafts: 4.2% (95% confidence interval [CI]: 3.7-4.6) and 10.8% (95% CI: 10.1-11.5) versus 6.5% (95% CI: 5.7-7.4) and 12.2% (95% CI: 11.2-13.3), respectively. However, after adjusting for potential confounders, associations disappeared with hazard ratios of 0.99 (95% CI: 0.87-1.13) for patient survival and 1.03 (95% CI: 0.94-1.14) for graft survival. Unadjusted risk of death-censored graft failure was similar, but after adjustment, it was higher for LUD transplants (1.19; 95% CI: 1.04-1.35). In conclusion, patient and graft survival of LRD and LUD kidney transplant recipients was similar, whereas death-censored graft failure was higher in LUD. These findings confirm the importance of both living kidney donor types.