An analysis of data 18 to 20 months after implementation of the kidney allocation system (KAS) shows a number of longer-term patterns, with success in a number of key system goals.
Trends include the following:
The volume of deceased donor kidney transplants performed increased by 6.9 percent from the year prior to KAS implementation to the 18 months afterward. This appears due to a substantial increase in deceased donation beginning in 2014 and continuing into 2016.
Significant “bolus effects” have occurred for candidates who received additional transplant priority under KAS, including those with very high immune sensitivity and those with lengthy dialysis times prior to transplant listing. Because the previous policy didn’t provide them as much priority, many of these candidates who had been waiting for years received a transplant soon after the new policy was implemented. The number of transplants per month for these candidates has declined as fewer are now listed for a transplant with high priority, but they are still being transplanted at rates higher than they were prior to KAS.
The percentage of transplant recipients experiencing delayed graft function (DGF) increased initially post-KAS but has since declined slightly. This finding may be influenced by the bolus effect for recipients who have been on dialysis longer-term.
The kidney discard rate after KAS has remained higher than the period before KAS implementation – from 18.5 percent pre-KAS to 19.8 percent at 18 months post-KAS. The increase was most noticeable for kidneys with a Kidney Donor Profile Index (KDPI) between 86 and 100 percent.
Transplants for pediatric patients (age 0-17) have declined slightly, although pediatric patients continue to receive priority that provides them much greater access to timely transplants than older candidates. Pediatric recipients are also more often receiving kidneys expected to last longer (lower KDPI) under KAS.
The six-month kidney graft survival rate (organ function post-transplant) decreased slightly but continues to exceed 95 percent. Similarly, the six-month patient survival rate has decreased slightly but remains above 97 percent.
The OPTN/UNOS Kidney Transplantation Committee will continue to analyze these trends carefully, as well as other data that will be available longer-term.
These recent findings are based on limited data. They must be interpreted cautiously and further tracked to assess whether observed trends will be sustained.
For additional reference, consult this article in the June 2016 edition of American Journal of Transplantation:
Stewart DE, Kucheryavaya AY, Klassen DK, Turgeon NA, Formica RN, Aeder MI. Changes in Deceased Donor Kidney Transplantation 1 Year After KAS Implementation. American Journal of Transplantation, 16(6), 1834-1847.