Muzaale AD, Massie AB, Al Ammary F, et al. - Given that the basis of live kidney donor candidate assessment is risk factors for kidney failure, researchers undertook this retrospective cohort analysis to quantify the risk for end-stage kidney disease (ESKD) by the biological link of the donor with the recipient, a risk factor not addressed by current clinical practice guidelines. This study included 143,750 US kidney donors. A median follow-up of 12 years was performed in donors. Compared with unrelated donors, greater risks by 259.4-fold, 4.7-fold, 3.5-fold for identical twins, full siblings, offspring, respectively, 1.0 for parents, and 1.0 for half-sibling or other biological relatives, for Asian donors. For identical twin donors, for full siblings, for offspring, for parents, and for half-sibling or other biological relatives, they noted 22.5-fold, 4.1-fold, 2.7-fold, 3.1-fold, and 1.3-fold greater risks, respectively, for black donors, and 3.5-fold, 2.0-fold, 1.4-fold, 2.9-fold, and 0.8-fold greater risks, respectively, for white donors. In this study, ESKD risk observed across types of donor-recipient association varied markedly for Asian, black, and white donors.