POS-714 POST-TRANSPLANT OUTCOMES IN RECIPIENTS OF LIVING DONOR KIDNEYS AND INTENDED RECIPIENTS OF LIVING DONOR KIDNEYS

Abstract

Although kidney transplant recipients (KTR) from living donors demonstrate superior post-transplant outcomes compared to deceased donor (DD) recipients, the relative contribution of recipient factors versus donor factors to outcome differences remains unclear. Comparing outcomes in DD recipients with only potential living donors (DD1) to those with actualized living donors (LD) and DD recipients without potential living donors (DD0) may help inform this question. We hypothesized that graft outcomes in the two DD groups (DD0 and DD1) will be similar, but inferior to the LD group. This was a retrospective cohort observational study of KTR presenting to our centre for evaluation between 01/01/06 and 31/12/18, and received a transplant during that time. They were followed to 31/08/19. KT candidates were classified based on whether they identified a potential living donor at evaluation (LD, DD1) or not (DD0), and their ultimate donor source (LD or DD1). Primary outcome was 5-year death-censored graft survival, adjusted for donor and recipient age, race, cause of end-stage kidney disease (ESKD), peak panel-reactive antibody (PRA), dialysis duration, acute rejection (AR), and delayed graft function (DGF). Within-group and between-group comparisons were made using paired/unpaired student t-test or chi-square/Fisher’s exact test. Graft survival was compared by Kaplan-Meier methodology and log-rank test, with independence of predictor variables by multivariate Cox proportional hazards. Significance was taken as p<0.05. There were 471 KTR (LD=152, DD1=85, DD0=234), excluding DD0 candidates becoming LD (N=8). The most common immunosuppressive regimen was tacrolimus, MPA, and prednisone. DD0 and DD1 did not differ in organ characteristics. LD had a higher 5-year eGFR (59.7 v 53.5 and 52.0 ml/min/1.73m2 for LD, DD1, DD0 respectively, p=0.009) and fewer graft losses (N=10, 10, 49). The 5-year graft survival is shown in Figure 1. DD0 trended inferior to DD1 (p=0.07) and was inferior to LD (p=0.002) while DD1 was not (p=0.19). By multivariate Cox regression analysis, LD demonstrated superior graft survival to combined DD (DD0+DD1) (HR 0.40 [95% CI 0.19-0.84], p=0.016) and DD0 (HR 0.34 [0.16-0.72], p=0.005) but not DD1 (p=0.72). AR, DGF, and diabetic ESKD were also significant across models. Adding peak PRA and dialysis duration rendered DD type insignificant. DD recipients are not all the same. DD1 may exhibit less inferior outcomes to LD than DD0 even with biologically equal DD organs. Not having an identified living donor at initial evaluation is a surrogate for factors risking graft survival that require further attention. Distinguishing DD0 from DD1 as a simple pre-transplant variable may permit clinicians to effectively target biological-social interventions and improve overall DD graft survival. Information about potential but non-actualized living donors must transfer to the DD recipient’s post-transplant chart.