A new UC Davis Health study has found that paediatric kidney transplant patients have better long-term outcomes when their kidney comes from living, biologically unrelated donors compared to deceased donors.

The study reviewed data from the Organ Procurement & Transplantation Network database from January 1, 2001, to Sept. 30, 2021.

Researchers compared the rates of graft failure (when the organ is rejected by the recipient) and death, as well as long-term outcomes of children who received kidney transplants from living related donors, living unrelated donors and deceased donors. It is the largest study of its kind and was published in the journal Pediatric Transplantation.

"The findings of our study should lay to rest any fears and concerns that centres have about accepting organs from unrelated living donors," said Lavjay Butani, senior author of the study and chief of pediatric nephrology at UC Davis Children's Hospital.

Butani added, "Living donation transplantation is superior to transplantation of organs from deceased donors in permitting better matching and management of the procured organ for the transplant surgery. Evidence from our large observational study shows that organs from living related donors are significantly better than deceased donor organs, whereas living unrelated donor transplants appear to be intermediate in risk between these two."

The study looked at 12,089 children who received a kidney transplant during the 20-year study period. Three hundred twenty-seven (2.7 per cent) children received kidneys from a living unrelated donor, 4,349 (36 per cent) received a kidney from a living related donor (80 per cent were parents, 6 per cent were siblings, 13 per cent were other relatives) and 7,413 (61 per cent) were from deceased donors.

To be included in the study, recipients needed to have a graft that had not failed on the day of the surgical procedure. The majority of recipients were on dialysis before their kidney transplant.

Graft loss is linked to the recipient's age

Recipient age was a predictor of graft loss. There was a higher risk of graft failure during the first post-transplant year in infants and pre-teens compared to teens. Interestingly, there was a lower risk of graft failure after the first post-transplant year in infants and pre-teens compared to teens.

Other predictors of graft loss found in the study are all previously well-established factors, including pre-transplant low albumin levels and the need for pre-transplant dialysis.

Source of kidney transplant matters

Deceased donor transplants had the poorest graft survival after the first year (4 per cent compared to 2.8 per cent of living related donors and 3.3 per cent of living unrelated donors). Even when human leukocyte antigen (HLA) matching between the donor and recipient is poor, those with living donor transplants fare better than transplants from deceased donors.

"Living donor transplants fare better than deceased donor transplants since the transplant can be planned," said Butani. "This planning allows for optimisation of the donor and recipient's health and minimising ischemic stress on the graft once it's procured from the donor."

The study found that over the past several decades, the number of living unrelated donors has increased progressively from 1.3 per cent in 1987 to 31.4 per cent in 2017.

"Our analysis suggests that living unrelated donor organ transplants are not inferior to deceased donor organs," said Daniel Tancredi, the study's co-author and professor in the Pediatrics Department at UC Davis Health. "This is especially important for children who are the most vulnerable of all and have much to benefit from receiving the best possible available donor organ."