Living donor transplantation: Should we advocate for it?

[Clark]

http://www.nephrologynews.com/articles/109977-article-headline

Living donor transplantation: Should we advocate for it?
By Milagros Samaniego

Living donor kidney transplantation offers multiple advantages to patients with end-stage renal disease in addition to economic and societal benefits. In comparison to deceased donor transplants, living donor transplantation leads to better patient and graft survival, fewer hospital admissions, and faster integration into family and societal life. This modality also allows access to transplantation to patients with humoral barriers by increasing the donor pool through paired kidney exchange programs. On the basis of these benefits and equivalent outcomes from living related or unrelated donors in the modern era of immunosuppression, living donor transplantation is now recommended as the best modality for kidney replacement therapy.

This preference bias is reflected by the increasing rates of living donation. From 1998 through 2004, living donor transplantation increased every year, and although there was a decline in rates from 2005-2008, in 2009 frequency of living donor transplantation increased by 7% compared with 2008. This increase in living donor transplant rates is noted for all age groups, races and ethnicities, but there are substantial geographical differences. Whereas rates of living donation are highest in New England and the north central United States, they remain lower in the southeast, possibly reflecting the higher rule out rates in African-American and Hispanic living donors.

All things being equal, living donor transplantation is considered safe and beneficial for both donor and recipient––but is it so? Although the majority of Caucasian living donors have excellent recipient and donor survival, and report a rewarding emotional effect and improvement in quality of life, the outcomes in racial minorities and ethnicities is not as clear. Meta-analyses using pooled-data analyses have shown that living donors may exhibit albuminuria and increase in systolic and diastolic blood pressures. More recently, a prospective controlled observational cohort study involving 8 centers in the United States showed that compared to controls, donors had a 28% lower measured (iohexol) glomerular filtration rates (GFR) at 6 months, 23% increase in intact PTH levels, 3.7% decrease in hemoglobin, 8.2% and 25% greater uric acid and homocysteine levels, respectively. These metrics are also present in patients with chronic kidney disease, and may contribute to progressive kidney dysfunction and/or major cardiovascular events. Supportive of this assertion, a recent population-controlled study reported that Norwegian living donors who donated between 1963 through 2006 had a higher hazard ratio for all-cause death (1.30, 95% CI 1.11-1.52), cardiovascular mortality (1.40, 95% CI 1.03-1.91), and ESKD (11.38, 95% CI 4.37-29.6) when compared to a control group of non-donors who would have been eligible for donation.

In a retrospective cohort study involving a Canadian and an American transplant program, African-Americans who donated between 1993 and 2006 had more hypertension than healthy non-donors African-Americans participating in a separate prospective cohort study. Of the donors with hypertension, 52.4% were untreated, 15.5% had an estimated GFR <60 mL/min/1.73m2, and 5.8% had microalbuminuria. But none has developed ESKD.

Transplant professionals not infrequently encounter potential living donors who are willing to donate a kidney despite identified risks either related to the surgical procedure or to the risk of developing chronic kidney disease in the future. The role of altruism and donor autonomy is not insignificant and can be considered as part of the risk/benefit ratio of living kidney donation. Because of the inadequate supply of deceased donor kidneys, the introduction of additional incentives may push the boundaries of who is now considered an acceptable donor. The transplant community needs to carefully evaluate any expansion of donor eligibility.