TUESDAY, Aug. 9 (HealthDay News) -- A new study appears to upend the long-held belief that black patients with kidney failure do better on dialysis than whites.

Researchers found that black patients younger than 50 years old who receive the blood-filtering process actually fare worse than whites.

"This is a brand new finding," said lead researcher Dr. Dorry L. Segev, an associate professor of surgery at Johns Hopkins University School of Medicine. "Before, all medical decision making, referral and medical care advice has been given under the pretext that blacks do better on dialysis. Now we know that's not true for young blacks."

In the United States, blacks are almost four times as likely as whites to develop end-stage kidney disease, according to background information in the study.

The findings suggest a need to rethink how younger black patients with kidney failure are counseled regarding their treatment options, the study said. While dialysis acts as a replacement for lost kidney function, the process is arduous, often interfering with work and family life.

Earlier studies looked at all blacks, not at different age groups, Segev said. For this study, the researchers reviewed information from the U.S. Renal Data System on 1.3 million people with end-stage kidney disease who received dialysis, and they separated the results by age.

Overall, the data showed that blacks did somewhat better on dialysis than whites: 63.5 percent of whites died during treatment compared with 57.1 percent of blacks.

However, when the researchers stratified the results by age, they found surprising differences. For blacks aged 18 to 30, the risk of death was about double -- about 28 percent vs. 14 percent for whites. In the 31-to-40 age group, blacks were 1.5 times more likely to die. Between the ages of 41 and 50, the increased risk of death narrowed to about 45 percent vs. 38 percent.

The report is published in the Aug. 10 issue of the Journal of the American Medical Association.

Why the success rates differ so dramatically is unclear. The researchers suspect "an interaction between the biology of the disease in younger blacks" and racial disparities in income and access to health care, Segev said.

"There is plenty of evidence to show that blacks have less access to health care than whites," Segev said. "If you have a disease that can tolerate that, then you will be OK. But if you have a disease that becomes out of control without health care, then you're not going to be OK."

Why older blacks do better on dialysis than whites also remains an open question, Segev added. It could be that only the stronger and healthier blacks reach dialysis, while others die beforehand, he speculated.

Access to kidney transplantation may also be a contributing factor, Segev said, referring to the study findings. "If you were 18 to 30 and white, you had a 55 percent chance of getting a transplant. If you were black, only 32 percent got transplants," he said.

Among all ages, 9.1 percent of blacks got kidney transplants, compared with 12.4 percent of white patients, and whites were more likely to receive a transplant kidney from a live donor. Segev said perhaps black family members are less willing to donate kidneys or maybe fewer black patients get referred for transplants.

Whatever the reason, more blacks should be referred for transplant, he said.

Dr. Ajay Singh, clinical chief of the renal division and director of dialysis at Brigham and Women's Hospital and an associate professor of medicine at Harvard Medical School in Boston, said the study "raises questions about whether socioeconomic factors or quality of insurance coverage might explain these findings."

Finding the answers to those questions is critical for improving clinical decisions and providing equitable care, the study authors concluded.

More information

For more information on dialysis, visit the U.S. National Library of Medicine.