We Need a Registry of Living Kidney Donors

On September 19, 2007, the board of the United Network for Organ Sharing deferred a decision to adopt uniform medical guidelines to protect the safety of living kidney donors. There is disagreement about what the guidelines should say, primarily because there is a lack of definitive data about the long-term health outcomes for living organ donors.

The UNOS decision came the same week that the journal Transplantation published a study by E.M. Gibney and colleagues documenting that, between 1993 and 2005, at least 102 (0.2 percent) of the 63,000 living kidney donors in the United States developed kidney failure and were listed for transplant themselves. Given the prevalence of kidney disease in the United States, this data might be taken to mean that living kidney donation is safe. After all, the risk of kidney disease increases with age for all of us. But the data are incomplete. The number of individuals on the transplant waiting list represents only a fraction of the total who have end stage renal disease (ESRD), and we have no reason to suspect that all former donors with ESRD are on the list. Some are excluded from transplantation because of comorbidities; others have seriously impaired kidney function or other health conditions but do not yet qualify for dialysis or transplant. Possibly the risk is better illuminated by data from Sweden (published in Transplantation in 2006), where researchers found that six (0.5 percent) of 1,112 living kidney donors had developed ESRD—a rate 2.5 times what Gibney and colleagues found.

The risk of developing ESRD after living kidney donation is apparently not evenly distributed. The Gibney article shows that of the 102 U.S. living kidney donors who were listed for transplant postdonation, most were male (64 percent) and the average age was fifty. (In Sweden, 83 percent were male and the average age was fifty-three.) Many in the United States were ethnic minorities: 44 percent were African Americans, and 12 percent were Hispanic. Since only 14 percent of all living donors are African Americans, African American donors appear to run an increased risk of ESRD, which mirrors the increased frequency of ESRD in the African American community at large. What is disconcerting, however, is that though the average length of time between donation and kidney failure was over fifteen years, ten U.S. donors—nine of them African American—were listed for transplant less than five years after donating. This is troubling because the screening process has been thought to ensure that donors are healthier than the average citizen.

Does this mean that African Americans should be excluded as living donors on grounds that we do not know how to identify those at increased risk of developing kidney disease themselves? Our answer is emphatically no. Most African American living donors do very well. What all prospective donors need is an accurate estimate of the risks of donation in order to make an informed decision.

The Gibney data underscore the need for a national registry that prospectively follows living kidney donors. Long-term data are needed about all-cause mortality, cardiovascular disease, blood pressure changes, the development of proteinuria or reduced creatinine clearance, and ESRD. The epidemic levels of obesity, with its risks for diabetes and kidney failure, and the growing acceptance in some transplant programs of less than ideal living donors (for example, individuals with some degree of hypertension), amplify both the risks of ESRD to donors and the need for better data.

Recent UNOS regulations require a transplant center to follow living donors for two years, but there is no funding for transplant centers to systematically follow these individuals. Instead, donors are referred back to their own physicians and lost to follow-up by the transplant community. Unfortunately, some are lost only until they return needing their own transplant. Living donors deserve better. The lack of support for a prospective large-scale living donor registry is morally inexcusable.