November 22, 2000

BIRMINGHAM, AL — Black Americans fare better now than they did seven years ago in the way donated kidneys are allocated for transplantation, but the playing field is still uneven, according to researchers at UAB (University of Alabama at Birmingham). An article entitled "Renal Transplantation in Black Americans" will appear in the November 23 issue of the New England Journal of Medicine (NEJM).

Dr. Robert S. Gaston, professor of medicine at UAB, wrote a report in 1993 that detailed disparities in the waiting period for black and white Americans to receive a donor kidney. “Today, for complex scientific and political reasons, white Americans still receive a disproportionately larger percentage of donated kidneys for transplant and black Americans still wait longer for transplantation,” Gaston said. UAB transplant surgeon Dr. Carlton Young wrote the report with Gaston.

Racial disparity appears very early in the process after the onset of end-stage kidney disease, Gaston and Young wrote. Among the factors are:

• Black patients are less likely than whites to be identified as transplant candidates.
  
  
• Blacks are less likely to appear on transplant waiting lists in the first year of eligibility.

Medicare, which pays for kidney dialysis or transplantation, has mandated that all patients undergoing dialysis be evaluated for transplantation. “One might expect this mandate to cause racial differences to wane, but this is not the case,” Gaston said. He cited several possible reasons including a medical evaluation process that is “daunting for many patients who have limited resources.”

Living donors are less of an option for black patients than whites, according to the NEJM article. One reason is because potential living-related black donors are more likely to be excluded because of previously undiagnosed health problems such as diabetes or high blood pressure. At UAB, only 13 percent of acceptable black candidates ultimately received a kidney from a living donor, compared with 33 percent of whites.

Cadaveric kidney transplantation is also problematic for black patients for socioeconomic and immunologic reasons. Patients are given greater preference if they have a closer genetic “match” with an available kidney. “The net result, however unintentional, is preference for white candidates for transplantation,” the article stated.

"Perfect matches are associated with a better transplant outcome and we have no quarrel with giving preference for a perfect match, even though whites are much more likely to benefit from this approach," the authors note. "Due to scientific advances, however, less-than-perfect matches make little difference in outcomes and should not exert a strong influence on who receives kidneys.”

The formula for allocating transplanted organs was modified soon after Gaston’s 1993 article in the Journal of the American Medical Association highlighted the issue. “At the very least, the effect of these modifications on minorities should be reassessed," Gaston said. "Indeed, it may be time to formulate an entirely new approach to organ allocation.”

The issue of kidney allocation is but a small part of overall problems relating to kidney failure in black Americans. Currently, blacks make up almost a third of patients with kidney failure while representing only 13 percent of the population. UAB researchers have played a leading role in developing information that links this anomaly to both environmental and genetic factors.

The authors said the scientific community should continue to search for explanations on why blacks develop kidney failure at a much higher rate than whites and should develop interventions early in the disease process. “It is sad to see so many patients from poor backgrounds who have never learned they have high blood pressure until they present to us with failing kidneys.”

Additionally, Gaston said, since black kidney transplant recipients fare worse than whites, there is a need for further advances in post-transplant care, including improved availability of transplant drugs and better understanding of ethnic differences in immune responses.

UAB is one of the largest kidney transplant centers in the world, having performed more than any other center in the past decade. A large portion of UAB's patients are black, due in part to the demographics of Alabama but also to the high incidence of hypertension in blacks, which frequently leads to kidney failure.

Gaston and Young called for greater efforts to “ensure that race is no longer an obstacle” to transplantation, the optimal therapy for end-stage kidney disease. “This is especially important since blacks are the most direly affected subgroup of patients with kidney failure.”