Kidney transplantation may offer survival benefit for patients on long-term dialysis

A new study finds that kidney transplantation prolongs the lives of not only patients who have recently initiated dialysis, but also those who have been undergoing dialysis for more than a decade. The findings, which appear in an upcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN), indicate that patients who may not have been referred for transplantation should be reevaluated.

In individuals with kidney failure, kidney transplantation is associated with longer survival than dialysis; however, this information comes from studies during an era in which patients received transplants relatively rapidly. Today, 13% of the nearly 100,000 wait-listed kidney transplant candidates in the United States have had kidney failure for more than 11 years.

John Gill, MD, MS (University of British Columbia and Vancouver's Providence Health Care) and his colleagues examined whether patients who receive transplants after prolonged treatment with dialysis derive a similar survival benefit as those who undergo transplantation earlier. "Because of recent changes in allocation policy, patients not previously wait-listed for many years can rapidly access transplantation if they are referred for transplantation and accepted onto a waiting list. We wanted to determine if these 'forgotten' patients might still benefit from transplantation despite being treated with dialysis for a very long period of time," said Dr. Gill. The researchers suspected that the benefit might not be the same because pre-transplant dialysis exposure is associated with inferior post-transplant kidney survival.

The team's study of 5365 patients in the Scientific Registry of Transplant Recipients determined the risk of death in recipients of a deceased donor kidney transplant after 10 or more years of dialysis treatment compared with wait-listed patients who continued to undergo dialysis. Patients were followed for at least 5 years.

The overall death rate for patients who underwent transplantation was 3.9 per 100 patient-years, compared with 5.8 per 100 person-years for patients who continued on dialysis. (A person-year is the number of years of follow-up multiplied by the number of people in the study.) After adjustments, transplant recipients had a 40% lower risk of dying than patients on dialysis who had equal lengths of follow-up from their 10-year dialysis anniversary. This benefit was observed in a variety of patient sub-groups, including patients ≥65 years of age and patients with diabetes. Transplant recipients were at higher risk of death for 180 days after transplantation, however, and they did not derive survival benefit until 657 days after transplantation, despite receiving good quality kidneys.

"Because transplantation is associated with longer survival in patients who have more than 10 years of dialysis treatment, patients who might not have been referred for transplantation should be reevaluated, as they might benefit," said Dr. Gill.