Recent studies provide valuable insights into the health of living kidney donors, including their future risk of chronic kidney disease and bone fractures. Research also finds a high willingness to be a living kidney donor in the United States once long-term health, medical bills, and other issues are addressed. Despite efforts to increase living donor transplantation, racial and ethnic disparities remain.
A small proportion of living donors experience kidney function decline after nephrectomy, a new study finds. In a Canadian cohort of 590 living kidney donors followed for a median 8.6 years, 47 donors (8.0%) had a sustained estimated glomerular filtration rate (eGFR) decline to less than 45 mL/min/1.73m2 or moderate to severe albuminuria, Ngan N. Lam, MD, MSc, of University of Calgary in Alberta, Canada, and colleagues reported in Kidney Medicine.1 The incidence rate was 9.2 per 1000 person-years. The median time to the outcome was 2.9 years, using 1 year after nephrectomy as the baseline.
Each 5 mL/min/1.73m2 lower predonation eGFR was significantly associated with a 26% increased risk of postdonation low eGFR or moderate to severe albuminuria, the investigators reported.
With respect to risk factors, donors had a 2.5- and 4.7-fold increased risk of developing low eGFR or albuminuria after surgery if they had predonation hypertension or postdonation diabetes, respectively.
“Further research is needed to determine whether donors with these risk factors would benefit from more diligent follow-up care as well as the effect of low eGFR and moderate-severe albuminuria on donor morbidity,” according to Dr Lam’s team.
The investigators lacked data on donor race, smoking history, and transplant-related characteristics.
A separate study of 103,938 living kidney donors in the US found that 75% of patients experienced a rise in serum creatinine exceeding 35% after donation.2 The incidence rate was 0.09 person-months. Compared with White donors, Black donors had a significant 22% increased risk of a serum creatinine rise exceeding 35%, whereas Asian donors had a significant 12% decreased risk, Ekamol Tantisattamo, MD, of the University of California Irvine School of Medicine, and colleagues reported at the 2023 ERA Congress. Hispanic and multi-racial patients had no greater risks in adjusted analyses. Older vs younger age did not affect this risk among Hispanic, Asian, and multiracial donors. Investigators gathered and analyzed data from the 1972-2022 Organ Procurement and Transplantation Network (OPTN) and Scientific Registry of Transplant Recipients (SRTR) database.
Living kidney donors have a theoretical excess risk of bone fractures due to lower kidney mass, lower serum 1,25-dihydroxyvitamin D, and increases in serum parathyroid hormone. In a comparison of survey responses from 2132 living kidney donors and 2014 healthy adults serving as a control group, the overall fracture incidence rate was a significant 11% lower for living kidney donors.3 The rate of vertebral fractures, however, was significantly increased 1.4-fold for living kidney donors compared with healthy adults, Rajiv Kumar, MBBS, of Mayo Clinic in Rochester, Minnesota, and colleagues reported in JAMA Network Open. The risk was higher for men than for women.
“Vertebral fractures would principally reflect deficits in trabecular bone, whereas all fractures, particularly in the axial skeleton, would principally reflect deficits in cortical bone,” Dr Kumar’s team explained.
They concluded, “Treatment of excess vertebral fractures with dietary supplements such as vitamin D3 may reduce the numbers of vertebral fractures and patient morbidity.”
Attitudes Toward Living Kidney Donation
To better understand national attitudes toward living kidney donation in the United States, Amy D. Waterman, PhD, of the J.C. Walter Jr Transplant Center at Houston Methodist Hospital in Texas, and colleagues conducted an online survey in June 2021 of 802 adults aged 25-65 years from the general public.4 Survey questions probed knowledge of living kidney donation and gauged willingness to donate.
Overall, 58.9% and 27.7% of respondents said they might or would consider donating a kidney while still alive, respectively. The vast majority of willing respondents would donate to a family member or close friend. At least half said they also would donate to an acquaintance (60.7%), a stranger with a personal profile (55.2%), or a stranger with no available profile (48.3%). Adults aged 45-54 years were most willing to donate, whereas the oldest adults aged 55-65 years were the least willing.
Barriers to living kidney donation included concern over possible negative health consequences (76.3%), fear of undergoing nephrectomy (72.6%), aversion to any kind of surgery (72.3%), and worries about affording related medical expenses (65.8%).
Transplant-related knowledge, such as kidney-paired donation, increased willingness to donate. Respondents most commonly reported accessibility to a replacement kidney (78.7%); information on the safety of nephrectomy (78.6%); information on health trajectory after donation (76.7%); payment/reimbursement of donation-related medical expenses (76.3%); and transplant success stories (75.2%) as factors that would increase their willingness.
Dr Waterman’s team cited progress in the field, including national efforts to increase federal funding for the National Living Donor Assistance Center, adjust financial thresholds to increase eligibility, reduce insurance discrimination against donors, modify the National Organ Transplant Act to allow government compensation for donors, improve accountability and transparency surrounding organ procurement and transplantation, and solicit public comments on potential improvements.
“These national-level efforts represent opportunities to further progress toward reduced costs for donors and increased rates of living kidney donation,” according to Dr Waterman’s team.
More work is clearly needed to improve access to living donor transplantation.
“Equitable access to organ transplantation is a guiding principle of the US organ allocation system,” Vineeta Kumar, MD, a board member of the American Society of Transplantation, said in an interview with Renal & Urology News. “Revisions to the national allocations system have made the rate of deceased donor kidney transplant for Black candidates after listing comparable with that of White candidates. However, Black patients receive living donor kidney transplants less frequently than White patients. Despite higher prevalence of end-stage kidney disease (ESKD), Black patients are less likely to be referred for kidney transplant evaluation and to be waitlisted than White patients.”
In a recent JAMA Network Open study,5 investigators studied 2 race-defined cohorts. Among 394,625 adults on the kidney waitlist, 33.1% were Black and 66.9% were White. Among 57,222 adults who received living donor kidney transplants, 14.1% were Black and 85.9% were White.
From 2008-2018, the racial gap between Black and White adults in living donor kidney transplantation persisted, Lisa M. McElroy, MD, MS, of Duke University School of Medicine in Durham, North Carolina, and colleagues reported. Black adults had a lower yearly median living donor kidney transplantation rate than White adults, ranging from 0.0577 to 0.771 center-years.
“Our findings observed geographic but no temporal variation and suggest that center participation in national programs, such as the paired exchange and voucher programs, may help to mitigate LDKT Black-White race inequities,” Dr McElroy’s team wrote.
In an accompanying editorial,6 Ashley Suah, MD, and Milda R. Saunders, MD, MPH, of the University of Chicago Medicine in Illinois commented, “Transplant centers should increase outreach within minoritized racial and ethnic communities to educate people about kidney health, transplantation, and living donation.”
Low rates of living kidney transplantation among Black Americans is a consequence of individual, interpersonal, and structural inequalities, according to an article in the Journal of Racial and Ethnic Health Disparities.7 Adoption of race-free eGFR equations was a necessary corrective measure. Socioeconomic conditions, poor communication with the provider, and lack of transplant knowledge are some of the remaining barriers.
A study published in the American Journal of Kidney Diseases8 found that Black potential donors are 75% less likely to accept a “medium” risk of kidney failure after living kidney donation compared with White potential donors. The closer the relationship Black potential donors had with the intended recipient, the greater their willingness to accept risk. Transplant professionals have the responsibility to understand a potential donor’s motivations and consider their best interests, according to the study authors.
“Addressing racial disparities in LDKT is a critical, multifaceted issue that demands our continued attention at all levels,” according to Dr Vineeta Kumar.