A Kidney Graft Survival Calculator that Accounts for Mismatches in Age, Sex, HLA, and Body Size

Abstract

Background and objectives

Outcomes for transplants from living unrelated donors are of particular interest in kidney paired donation (KPD) programs where exchanges can be arranged between incompatible donor-recipient pairs or chains created from nondirected/altruistic donors.

Design, setting, participants, & measurements

Using Scientific Registry of Transplant Recipients data, we analyzed 232,705 recipients of kidney-alone transplants from 1998 to 2012. Graft failure rates were estimated using Cox models for recipients of kidney transplants from living unrelated, living related, and deceased donors. Models were adjusted for year of transplant and donor and recipient characteristics, with particular attention to mismatches in age, sex, human leukocyte antigens (HLA), body size, and weight.

Results

The dependence of graft failure on increasing donor age was less pronounced for living-donor than for deceased-donor transplants. Male donor–to–male recipient transplants had lower graft failure, particularly better than female to male (5%–13% lower risk). HLA mismatch was important in all donor types. Obesity of both the recipient (8%–18% higher risk) and donor (5%–11% higher risk) was associated with higher graft loss, as were donor-recipient weight ratios of <75%, compared with transplants where both parties were of similar weight (9%–12% higher risk). These models are used to create a calculator of estimated graft survival for living donors.

Conclusions

This calculator provides useful information to donors, candidates, and physicians of estimated outcomes and potentially in allowing candidates to choose among several living donors. It may also help inform candidates with compatible donors on the advisability of joining a KPD program.