Why are African-American patients with end-stage renal disease (ESRD) less likely to be placed on waiting lists for kidney transplantation? It's not because they live farther away from transplant centers, reports a study being presented at the American Society of Nephrology's 40th Annual Meeting and Scientific Exposition in San Francisco.

However, black patients who live in poorer neighborhoods are less likely to be placed on transplant waiting lists than white patients. "This finding warrants further exploration but suggests that racial disparity in the waitlisting process may indeed be a reflection of differential access to healthcare," comments Dr. Sandra Amaral of Emory University, co-author of the study.

The researchers analyzed the relationship between being placed on a transplant waiting list and distance from a patient’s residence to the nearest transplant center among ESRD patients in Georgia and the Carolinas from 1998 to 2002. Waitlisting status was assessed using data from the United Network for Organ Sharing.

Of 12,572 ESRD patients in the study, 17 percent were placed on the waiting list for a kidney transplant. Sixty-two percent of the ESRD patients were black, while 17 percent lived in impoverished neighborhoods. Compared to non-Hispanic whites, blacks were more likely to live in high-poverty areas: 27 percent of black patients (versus nine percent of whites) resided in areas with greater than 25 percent of the population living below the poverty line. Forty-four percent of the patients had diabetes-related ESRD, while 70 percent had other medical problems besides kidney disease.

The researchers hypothesized that patients living farther from transplant centers would be less likely to be placed on the transplantation waiting list. However, distance to the transplant center did not significantly affect the chances of being waitlisted. The patients lived an average of 49 miles from the nearest transplant facility.

In contrast, black patients living in poorer neighborhoods—based on U.S. Census data—were less likely to be placed on the waiting list than whites patients. There appeared to be no significant racial difference in waitlisting in higher-income neighborhoods.

"Black patients were 56 percent less likely than white patients to be waitlisted for transplantation in the most impoverished neighborhoods," says Dr. Amaral. Other characteristics affecting the chances of being put on the waiting list included sex, age, body mass index, and baseline clinical parameters, such as presence of anemia or hypoalbuminemia.

"Racial disparities persist in the U.S. transplantation process," according to Dr. Amaral. "The reasons for this are poorly understood, but multiple factors are likely involved." The new results show that distance from transplant centers does not affect the likelihood of being waitlisted or explain racial disparity in the waitlisting process. However, community poverty does appear to be a significant factor. "To our knowledge, this is the first study to examine the impact of community poverty on racial disparity in transplant waitlisting," says Dr. Amaral. "It also introduces a potential new approach to addressing the disparities: reaching out to poorer communities with advocacy and education."

The study abstract, "Distance to Nearest Transplant Center Is Not Associated with Racial Disparities in Placement on a Kidney Transplant Waiting List," (SU-FC123) will be presented as part of a Free Communications session on the topic of “Kidney Transplant Outcomes: Epidemiology, Clinical Trials and Health Services Research” on Sunday, November 4 at 4:24 PM in Room 2005 of the Moscone Center.