Data from 2016 show ongoing positive trends in short-and long-term allograft survival, and a decrease in the number of active listed candidates for the first time in more than a decade, with a concomitant increase in deceased donor kidney transplants. Transplant rates that had changed dramatically for some groups after implementation of the new kidney allocation system in 2014 are stabilizing, allowing for evaluation of new steady states and trends. Many challenges remain in adult kidney transplantation, including stagnant rates of living donor transplant, geographic disparities in access to transplant, racial disparities in living donor transplant, and overall a continuing demand for kidneys that far outpaces the supply. For pediatric recipients, a decline in the proportion of living donor transplants is of concern. In 2016, only 34.2% of pediatric transplants were from living donors, compared with 47.2% in 2005. The number of related donors decreased dramatically over the past decade, and the number of unrelated directed transplants performed in pediatric candidates remained low (50).

A new kidney allocation system, expected to be implemented in late 2014, will characterize donors on a percent scale (0%-100%) using the kidney donor profile index (KDPI). The 20% of deceased donor kidneys with the greatest expected posttransplant longevity will be allocated first to the 20% of candidates with the best expected posttransplant survival; kidneys that are not accepted will then be offered to remaining 80% of candidates. Waiting time will start at the time of maintenance dialysis initiation (even if before listing) or at the time of listing with an estimated glomerular filtration rate of 20 mL/min/1.73 m 2 or less. Under the current system, the number of candidates on the waiting list continues to increase, as each year more candidates are added than are removed. Median waiting times for adults increased from 3 years in 2003 to more than 4.5 years in 2009. Donation rates have not increased. Short-term outcomes continue to improve; death-censored graft survival at 90 days posttransplant was 97% or higher for deceased donor transplants and over 99% for living donor transplants. In 2013, 883 pediatric candidates were added to the waiting list; 65.8% of pediatric candidates on the list in 2013 underwent deceased donor transplant. Five-year graft survival was highest for living donor recipients aged younger than 11 years (89%) and lowest for deceased donor recipients aged 11 to 17 years (68%).

The first full year of data after implementation of the new kidney allocation system reveals an increase in deceased donor kidney transplants among black candidates and those with calculated panel-reactive antibodies 98%-100%, but a decrease among candidates aged 65 years or older. Data from 2015 also demonstrate ongoing positive trends in graft and patient survival for both deceased and living donor kidney transplants, but the challenges of a limited supply of kidneys in the setting of increasing demand remain evident. While the total number of patients on the waiting list decreased for the first time in a decade, this was due to a combination of a decrease in the number of candidates added to the list and an increase in the number of candidates removed from the list due to deteriorating medical condition, as well as an increase in total transplants. Deaths on the waiting list remained flat, but this was likely because of an increasing trend toward removing inactive candidates too sick to undergo transplant.

In 2013, the Organ Procurement and Transplantation Network in the United States approved a new national deceased donor kidney allocation policy that introduces the kidney donor profile index (KDPI), which gives scores of 0%-100% based on 10 donor factors. Kidneys with lower KDPI scores are associated with better post-transplant survival. Important features of the new policy include first allocating kidneys from donors with a KDPI#20% to candidates in the top 20th percentile of estimated post-transplant survival, adding waiting time from dialysis initiation, conferring priority points for a calculated panelreactive antibody (CPRA).19%, broader sharing of kidneys for candidates with a CPRA$99%, broader sharing of kidneys from donors with a KDPI.85%, eliminating the payback system, and allocating blood type A2 and A2B kidneys to blood type B candidates. We simulated the distribution of kidneys under the new policy compared with the current allocation policy. The simulation showed increases in projected median allograft years of life with the new policy (9.07 years) compared with the current policy (8.82 years). With the new policy, candidates with a CPRA.20%, with blood type B, and aged 18-49 years were more likely to undergo transplant, but transplants declined in candidates aged 50-64 years (4.1% decline) and $65 years (2.7% decline). These simulations demonstrate that the new deceased donor kidney allocation policy may improve overall post-transplant survival and access for highly sensitized candidates, with minimal effects on access to transplant by race/ethnicity and declines in kidney allocation for candidates aged $50 years.

Many positive trends in kidney transplantation were notable in 2017. Deceased donor kidney transplant rates and counts continued to rise, the kidney transplant waiting list declined for the third year in a row after decades of growth, and both short-and long-term allograft survival continued to improve year over year. In total, more than 220,000 patients were living in the United States with a functioning allograft. With 3 years of data available since implementation of the new kidney allocation system, better prediction of longer-term results of the allocation policy changes became possible. The data also reveal several areas in need of improvement and attention. Overall, the challenge of providing adequate access to kidney transplant persisted nationally, with additional dramatic regional variation. The proportion of living donor kidney transplants in both adults and children continued to fall, and racial disparities in living donor kidney transplant grew in the past decade. Patients at start of year 99,322 98,018 95,658 Patients added during year 30,215 30,854 30,918 Patients removed during year 31,466 33,167 33,891 Patients at end of year 98,071 95,706 92,685