Upcoming improvements to allocation of deceased donor kidneys for candidates in the U.S. will likely improve overall patient survival and lengthen kidney function, according to a study published online on May 15 by the Journal of the American Society of Nephrology (JASN).
The work was led by the Scientific Registry of Transplant Recipients (SRTR), which conducts data analyses and simulation modeling to support transplant policymaking and public understanding of donation and transplantation. The Chronic Disease Research Group of the Minneapolis Medical Research Foundation serves as the SRTR under federal contract. Coauthors included Drs. John Friedewald and Richard Formica, past and current chairs of the OPTN/UNOS Kidney Transplantation Committee, as well as UNOS staff members Wida Cherikh, Ph.D., and Darren Stewart, M.S., and former UNOS staff member Ciara Samana, M.S.P.H.
The revisions to kidney allocation policy, to be implemented in late 2014, will match kidneys likely to have the longest potential function more often with the candidates predicted to need a longer functioning transplant. They will also provide additional priority for candidates with biological disadvantages in transplant access, such as having a hard-to-match blood type or a high immune sensitivity to the majority of kidneys that could be offered to them.
Simulation modeling of the likely effects of the revised system predicts that transplant recipients as a group will have increases in both patient survival and graft survival (continued function of the transplanted kidney). Assuming 11,000 transplants are performed each year (a continuation of the current yearly rate), the overall group of recipients could gain 9,130 additional “life-years” of patient survival and 2,750 years of continued kidney function. The median “years of life” post-transplant (the statistical estimate of the amount of time 50 percent of patients are expected to live after a transplant) is predicted to increase by seven percent, from 11.82 years to 12.65 years. The median graft survival for recipients is also predicted to increase by 2.8 percent.
The simulation modeling predicts that candidates more likely to receive transplants under the new system will include those who are between the ages of 18 and 49, those who have blood type B, and those who have a moderate or extremely high immune system sensitivity based on the calculated panel reactive antibody, or CPRA. The modeling estimates a small decline in transplants for candidates age 50 or older.
It is important to note that the modeling results only estimate potential outcomes for all kidney transplant recipients nationwide. They do not predict the individual experience of any given transplant patient, transplant hospital or local donation service area.