Older kidney recipients can benefit from organs from older donors. But previous cerebrovascular disease may reduce the survival benefits of these kidney transplants, according to a recent study.
Living donors are now getting their due as a medical population of interest that will be officially monitored for health outcomes and other data over time.
A pilot study at 10 transplant centers began enrolling donors for the Living Donor Collective, a living donor registry, in January 2018 and will enroll through September 2019 (Table 1). After that, the registry will begin enrolling at other transplant programs nationwide. A wide variety of medical and other data will be gathered through a questionnaire survey to learn more about health parameters and why people do or do not choose to donate.
By contrast, organ recipients have been tracked carefully for nearly 35 years. Since 1984, when Congress passed the National Organ Transplantation Act, there has been a mandate for a national registry for organ matching, with a scientific registry of the recipients of organ transplants. That act led to the founding of the Scientific Registry of Transplant Recipients (SRTR) and the Organ Procurement and Transplantation Network (OPTN) (1).
It was not until recently, however, that the federal Health Resources and Services Administration (HRSA) that administers the SRTR and OPTN called for the formation of a Living Donor Collective, a similar registry for living donors.
SRTR now is establishing a national registry to address important questions about health outcomes, long-term safety of donation, and why the number of living donors has decreased in recent years for both kidney and liver donors.
According to an article published in the American Journal of Transplantation about the formation of the collective, living donor kidney transplant procedures in the United States decreased by 14.3% in an 11-year span (2). The peak was 6572 in 2005, and the number fell to 5629 in 2016. (During the same period, however, the number of deceased donor kidney transplant procedures increased 35.5%, from 9913 in 2005 to 13,431 in 2016.)
Similarly, liver donation among living donors in the United States has dropped off since an annual high of 524 donors in 2001 (2). While just 219 living donor liver transplants were performed in 2009, this number had increased to 345 in 2016. Authors of the Living Donor Collective article conjectured that a report about a living donor death most likely led to the decline after 2001.
Emphasis on living donor health has been gaining attention. A 2018 study published in the Annals of Internal Medicine used 52 observational studies to extract medical data and report on the health of 118,426 living kidney donors and a comparison group of 117,656 nondonors (3).
The Annals study found that living kidney donors had higher mean diastolic blood pressure, higher mean serum creatinine levels, a lower mean estimated glomerular filtration rate, and lower high-density lipoprotein cholesterol than the nondonors (3).
Living kidney donors had an almost 9-fold greater relative risk (RR) for developing end-stage renal disease (8.83; 95% CI, 1.02–20.93), Medscape reported, calling this finding perhaps the “most striking” of all (4). The health website was quick to note, however, that the “absolute risk for ESRD among donors was very low,” with an incidence rate of 0.5 events per 1000 person-years compared with 0.1 event among nondonors.
In female living donors, a higher rate of post-donation preeclampsia, a problematic high blood pressure, emerged as a problem. The Annals study noted that previous studies had reported preeclampsia as a more common condition among living kidney donors than in the general population. The authors cautioned that the ability to generalize about living donors in the study was limited by the selected control populations of the studies examined.
Based on articles like the Annals observational study and other studies on living donors, the new collective will carefully document medical findings, and, for example, “place a high priority on establishing the risk of kidney donation with regard to pregnancy” and plans to develop a survey instrument for pregnancy complications (2).
Nondonor information also is considered an important part of the Living Donor Collective data gathering. The collective’s work will help transplant centers understand the reasons that prevent living donor candidates from donating. “Only by following donor candidates who are turned down or decide not to donate due to concerns that donation would adversely affect their health can we determine whether those concerns are justified,” wrote the study authors.
The 10 pilot study sites will work to develop a survey for future sites. The survey will include both medical and psychosocial issues that are important to candidate donors and actual donors.
The pilot program will need to determine the best routes through which to contact participants—mail, email, social media, or phone—about one year after donation or a year after the person decides not to donate, and every one to two years after that. A website for donors will share outcomes and other information that may be helpful.
Transplantation centers will have the ability to ask their own specific questions of donors and potential donors. Through its relationship with the federal agency HRSA, SRTR can help investigators gain access to information to conduct studies that will improve the understanding of living donation outcomes.
Emilio D. Poggio, MD, from Cleveland Clinic, and Peter P. Reese, MD, from the University of Pennsylvania, wrote that the findings by Emanuele Di Angelantonio, MD, of the University of Cambridge in England and colleagues offer insights into the medical risks of living donation.
Until more is known, “we should do our best to protect potential donors with careful selection, candor about harms, open discussion about unknowns, and a commitment to their lifelong health after nephrectomy,” they wrote in an accompanying editorial published in the Annals (5).
With the information from the pilot program’s new data sets, a more focused description of living donors and their health over time will emerge, and challenges faced by the national donation system can better be addressed.
Leppke S, et al.. Scientific Registry of Transplant Recipients: Collecting, analyzing, and reporting data on transplantation in the United States. Transpl Reviews 2013; 27:50–56.
Kasiske BL, et al.. The Living Donor Collective: A scientific registry for living donors. Am J Transpl 2017; DOI: 10.1111/ajt.14365.
O’Keeffe LM, et al.. Mid- and long-term health risks in living kidney donors: A systematic review and meta-analysis. Ann Intern Med 2018; DOI: 10.7326/M17-1235.
Poggio, ED, Reese PP. The quest to define individual risk after living kidney donation. Ann Intern Med 2018; DOI: 10.7326/MI17-3249.