New priorities: Analysis of the New Kidney Allocation System on UCLA patients transplanted from the deceased donor waitlist

Abstract

UNOS implemented a new Kidney Allocation System (New KAS) on December 4, 2014 with a primary goal of increasing equity to organ transplant for patients that were immunologically or socially disadvantaged by the previous allocation system (Previous KAS) that prioritized long wait times. We examined the effects of the New KAS on patients transplanted from the UCLA deceased donor waitlist during the first year and compared to the last year of the Previous KAS. The total number of deceased donor kidney transplants was increased in the New KAS as compared to the Previous KAS (178 vs 148). Transplant of regraft patients and of highly sensitized patients with cPRA⩾99% was significantly increased in the New KAS (New KAS vs Previous KAS, 29.8% vs 11.5%, p⩽0.0001, and 26.4% vs 2.7%, p⩽0.0001, respectively). In the New KAS, the percentage of patient's receiving allografts imported from outside our local area was also significantly increased (34.8% vs 15.5%, p<0.0001). In the New KAS, 59.7% and 48.3% of imported organs were allocated to very highly sensitized (⩾99% cPRA) or re-graft patients, respectively, as compared to 8.7% and 8.7% during the Previous KAS (p<0.001). Recipients and donors with age differences exceeding 15years were decreased in the New KAS as compared to the Previous KAS (36.5 vs 48.7%, p⩽0.032). There was a 40.1% reduction in transplant to patients in the 65+ age group in the New KAS (p⩽0.025). The percentage of patients transplanted with preformed donor specific antibody (DSA) was similar in the New as compared to the Previous KAS (19.7% vs 15.5%) and, patients were transplanted with a range of 1-3 preformed DSA of weak to moderate strength. Cold ischemic time was significantly increased over all organs, and in patients transplanted with preformed DSA during the New as compared to the Previous KAS (17.5 vs 19.1h and 17.2 vs 22.2, p<0.04 and p<0.03, respectively). Episodes of delayed graft function and the number of biopsies for cause were similar between the New and the Previous KAS. However, there were more events of biopsy proven antibody mediated rejection in patients transplanted since the start of the New KAS. The data show that the New KAS is working at the center level as designed to better age match recipients and donors and to increase transplantation of very highly sensitized patients through broader sharing.

Keywords: Donor specific antibody; Kidney Allocation System; Renal; Transplant; UNOS.