For decades, people have been puzzled by the differences in kidney transplant outcomes among certain populations. When we look at national statistics, kidneys transplanted into Asian and white patient populations have a greater longevity and survival opportunity than kidneys transplanted in black and Native American patient populations.
Many researchers have investigated this problem, but no one has yet developed indisputable reasoning to explain it.
While much of past research has created even more questions, Hopkins experts believe that they may be at the beginning of a research project that will identify some of the answers.
Recently, Hopkins researchers examined the differences in outcomes among various populations in our local patient communities. The preliminary study revealed some valuable insights that could assist Hopkins patients. Next, Hopkins scientists expect to conduct this research on the national level. As with much of research, comprehensive national findings have the potential to assist the medical community make more informed decisions to improve outcomes for all patients, regardless of the patient’s background.
For the local and national research, Hopkins experts wanted to answer the question "why does one population of patients lose transplanted kidneys at a more rapid rate than another?"
To begin this investigation, Hopkins Medical Institute researchers - J. Keith Melancon, M.D., primary investigator, Christopher Simpkins, M.D., Richard Ugarte, M.D., and a team of clinical specialists - reviewed information about kidney patients who have been transplanted at Hopkins. They wanted to explain what risk factors are key in leading to disparities in kidney transplantation outcomes.
"Past research has helped medical teams achieve important advances |
Researchers examined the information on patients who had been cared for by the transplant team at Hopkins. It was important to narrow the research question to compare just two populations, yet the researchers had to find groups where the most information was available. At Hopkins, that meant researchers conducted a comparison of data of white versus black patient populations. They identified close to twenty potential risk factors that might be the cause of the differences in outcomes among white versus black individuals. Next, the team poured over the data and used different mathematical equations to try to identify the primary risk factors. At the end of the research, they had identified three likely risk factors that have a greater impact on local black versus white patient populations.
The three primary factors that did increase the risk of losing the transplanted kidney in the black patient population were: (1) the age of the donor; (2) the length of time that the organ had to be preserved when it was transplanted from the donor to the recipient; and (3) the social and economic status related to the area where the recipient lived.
In other words, the researchers determined that there was a significant difference in outcomes for a white patient as compared to a black patient, even when they each had received an organ from a donor who was the same age.
Also, the outcome differences continued to appear, even when the researchers compared white versus black populations who lived in areas that were similar in social class and household income.
Are these risk factors facing Hopkins patients the same as the ones facing patients at transplant centers across the country?
The researchers intend to use this study as a starting point to review outcomes data on a national level. Hopkins researchers would like to determine if the findings in the local study can be applied to the nation as a whole.
We will not know more about this until the research team completes the next part of their study. However, we do anticipate new study findings will be published by many of the key researchers on the team.
Dr. Simpkins has committed to pursuing this line of research as one of his primary activities for the next couple of years.
Similarly, Dr. Ugarte has been involved in research on kidney transplantation for the past three years. His research is geared toward improving the outcomes for all kidney transplant patients, and his research has always included a special look at African Americans. " I chose to do research in this area because half of Hopkins transplant recipients are African American and I would like to see them keep their transplants as long as possible," comments Dr. Ugarte.
Finally, the primary investigator in this research, Dr. Melancon, has always been passionate about uncovering the mysteries behind disparities in transplantation.
Says Dr. Melancon, "Significant research findings can help doctors make better choices to prevent loss of kidneys in the minority patients they treat. It may even help us improve national transplant policies– UNOS [the national organization that regulates the transplant field] depends on solid research results to be the foundation of their policies." The transplant community will see more Hopkins results published to help transplant teams, policy makers and patients for years to come.
Researchers who have contributed to the preliminary study are: J. Keith Melancon, M.D. (primary investigator), Christopher Simpkins, M.D., Richard Ugarte, M.D. , Neil R. Powe, M.D., M.P.H., Ebony Boulware M.D., M.P.H., Richard Thompson, Ph.D., Dan Warren, Ph.D., Dorry Segev, M.D., Robert Montgomery, Ph.D., Andrea Zachary, Ph.D., M. Sue Leffell, Ph.D. Chris Handley of Transplant Resource Center also contributed to this research.
At the time of printing, Christopher Simpkins, M.D., Richard Ugarte, M.D were preparing to co-author the results of the first study for publication in a medical journal. For the details on where you can find the researchers’ published article, check the "what’s new" section of the Comprehensive Transplant Center’s webpage: www.hopkinsmedicine.org/transplant
Information on where to find the researchers’ published article will also be in the next Bridges issue.
