WEDNESDAY, June 4 (HealthDay News) -- A range of biological, social and health care-related factors are responsible for the ethnic and racial disparities in results for U.S. patients with kidney disease, according to two new studies.

Previous research has shown that black and Hispanic kidney disease patients are more likely than white patients to develop kidney failure requiring dialysis or transplantation, according to background information in a news release about the studies.

A recently released U.S. government report said that black patients with end-stage renal disease (ESRD) account for 33 percent of all patients on the kidney transplant wait-list, even though blacks make up only 13 percent of the general population. Blacks with chronic kidney disease progress faster to ESRD than white patients and are much more likely to develop ESRD and to do so at an earlier age than whites.

Another federal government report said black patients with kidney disease are almost as likely as white patients to receive adequate dialysis, but the proportion of black patients registered on the kidney transplant wait-list is much lower than that of whites.

In one of the new studies, researchers identified a number of factors that play a role in these and other disparities: lack of patient trust; cultural and communication barriers; residential segregation that groups minorities in communities with lower quality health care; lower rates of insurance among minorities; and under-representation of minorities in clinical trials.

Health care providers can directly address some of these factors, said study authors Dr. Keith Norris of Charles R. Drew University in Lynwood, Calif., and Dr. Allen Nissenson of the University of California, Los Angeles.

"As a medical profession, we too frequently believe that many health issues are beyond our impact, citing them as societal issues, not realizing that we are society," wrote Norris and Nissenson. They encouraged doctors to effectively communicate with patients, to advocate for improved health care systems, and to investigate the situation by conducting relevant medical research.

The study is in the July issue of the Journal of the American Society of Nephrology.

A second study in the same issue of the journal also identified a number of factors that contribute to racial and ethnic disparities among kidney disease patients in the United States, including: genetic incompatibility; wait-list registration practices; donor kidney acceptance practices; patient interest in transplantation; attitudes and beliefs about organ donation; and differences in risk factors for kidney disease progression after transplantation.

"There is a professional, economic, and ethical imperative to eliminate health disparities. We have the means to find and implement solutions by holding ourselves, and others, accountable," wrote study author Dr. Neil Powe of the Johns Hopkins Medical Institutions in Baltimore, who suggested a number of steps that can be taken by doctors and others.

For example, researchers should examine why black and Hispanic patients with kidney disease are more likely than whites to progress to ESRD. Is it due to biological factors such as genetics, non-biological factors such as poverty, or lack of optimal care, or a combination of both?

Health providers and health care delivery organizations need to take action to eliminate disparities, and the nation's health care policies need to be changed, Powe said.

"The kidney disease community should strongly advocate for solutions that address broader issues, such as lack of awareness of kidney disease and its prevention, inadequate health insurance, and forces leading to the concentration (if not segregation) of care of racial and ethnic minorities to certain institutions, providers, and community services," he wrote.

More information

The U.S. National Kidney Disease Education Program has more about kidney disease.