#1216 Comparable outcomes for old, older and very old deceased donors in old kidney transplant recipients

Abstract

Abstract Background and Aims Old patients (≥ 65 years) make up almost 1/3 of the waiting list for kidney transplantation in the Netherlands, and this proportion continues to rise. These patients have a high waitlist mortality and benefit from early transplantation, even with kidneys from older or ‘marginal’ donors. Transplanting marginal donor kidneys may help to cut the proportion of elderly patients on the waiting list and improve clinical outcomes. More epidemiological support regarding the graft outcomes of old, older and very old donor kidneys is needed to support clinicians in accepting these kidneys. We therefore studied the outcomes of these kidneys in old recipients. Method Retrospective cohort study of all kidney transplant recipients ≥ 65 years with a deceased donor ≥ 65 years in the Netherlands between 2005 and 2022. Discarded kidneys from deceased donors ≥ 65 years in the same time period were included as well. Donors were categorized into old (65-69 years, OD), older (70-74, OD+) and very old (75+, OD++). Results We included 1301 transplantations from donors ≥ 65 years, of which 435 from an OD+ and 90 from an OD++. Median recipient age was 69 years (66 - 72), 67% was male. The transplanted OD+ and OD++ kidneys were more often from DBD donors (OD 42%, OD+ 51.3%, OD++ 70%, P < 0.01) with lower nadir creatinine compared to the OD kidneys (61.0 umol/l [51.0, 74.0] vs. OD+ 59.0 [49.0, 72.0] P = .034, vs OD++ 58.0 [49.0, 64.5] P = .021). Patient survival was similar for recipients of OD, OD+ and OD++ kidneys at one year (91% vs 89% vs 93%, respectively; Plog-rank = 0.3) and at five years (60% vs 60% vs 64%; Plog-rank = 0.2) after transplantation. Additionally, in multivariable Cox regression, donor age category was not associated with recipient mortality risk (Ref = OD. OD+: P = .7; OD++: P = .2). Death-censored graft survival was ≥92% in all groups after 1 year, and did not differ significantly between donor age categories (PGray's = 0.2). Results remained non-significant in multivariate Cox regression (Ref = OD, OD+: P = .942; OD++: p = 0.403). Kidneys offered but not accepted for transplantation (before procurement) had a higher serum nadir creatinine in comparison with transplanted kidneys (68 umol/L [56 - 84] vs 61 umol/L [51 - 78], P < .001), and were more often from DCD donors (79% vs 53%, P < .001). However, donor characteristics of many discarded kidneys resembled that of successfully transplanted kidneys. Conclusion Recipient and graft survival are good and similar for old patients receiving kidneys from old, older and very old deceased donors. These findings may contribute to a wider acceptance of kidneys from these donors.