According to the US Department of Health & Human Services, 12,095 kidney donations took place in the US last year, of which 5,178 were from living donors. But new research published in JAMA suggests that living kidney donors may have a small increased risk of developing kidney disease after donation, compared with healthy non-donors.

The availability of living donations is critical for those who suffer end-stage renal disease (ESRD). Living kidney donations are associated with more timely transplants and better recipient outcomes, compared with kidney donations from deceased individuals.

But researchers from the Johns Hopkins University School of Medicine in Baltimore, MD, led by Dr. Abimereki D. Muzaale, say it is “imperative that the transplant community, in due diligence to donors, understands the risk of donation to the fullest extent possible and communicates known risks to those considering donation.”

For the study, the research team analyzed the incidence of ESRD in 96,217 individuals in the US who donated a kidney between 1994 and 2011, and compared this with the incidence of ESRD in healthy non-donors who were a part of the Third National Health and Nutrition Examination Survey (NHANES III).

All participants were linked to the Centers for Medicare & Medicaid Services data, which monitors the development of ESRD. Data includes participants’ placement on the transplant waiting list, the initiation of maintenance dialysis and the receipt of a living or deceased donor kidney transplant.

From the analysis, the researchers found that 15 years after donation, the estimated cumulative incidence of ESRD was 30.8 per 10,000 for donors and 3.9 per 10,000 for healthy non-donors.

The researchers estimated participants’ lifetime risk of ESRD by the age of 80. They found this was 90 per 10,000 in donors and 14 per 10,000 in healthy non-donors.

However, the investigators note that lifetime risk of ESRD for living donors is still significantly lower than in the general population. At present, lifetime risk of ESRD in unscreened donors is 326 per 10,000.

Commenting on the findings, the researchers say:

Compared with a matched cohort of healthy non-donors, kidney donors had an increased risk of ESRD. However, the magnitude of the absolute risk increase was small. These findings may help inform discussions with persons considering live kidney donation.”

In a comment piece linked to the study, Dr. John S. Gill of the University of British Columbia and Dr. Marcello Tonelli of the University of Alberta, both in Canada, note that these findings reveal a very low absolute risk of ESRD after live kidney donation, and that these findings should not influence existing clinical practice.

“The findings by Muzaale and colleagues demonstrating the low absolute risk of ESRD should reassure future donors of the safety of living kidney donation,” they write.

“It is known that focusing on relative increases in risk, rather than absolute increases in risk, can unduly influence treatment decisions, especially for rare outcomes.”

They continue:

“[…] It would be prudent for clinicians to emphasize the absolute risk of ESRD in discussions with prospective living donors, ideally using a decision aid that will facilitate the process of obtaining informed consent.”

Late last year, Medical News Today reported on a study suggesting that pig kidneys could be used to build human kidneys suitable for transplantation.