A proposed new system for assigning kidneys to patients waiting for transplants would reduce the median waiting time for transplantation from approximately 24 to 14 months and improve equity for African-Americans and women, according to the author of a study published in a journal of the Institute for Operations Research and the Management Sciences (INFORMS®).
The proposal, an alternative to the system currently employed by the United Network of Organ Sharing (UNOS), would also increase the overall likelihood of transplantation from 45% to 61% and increase quality-adjusted life expectancy from 32.7 months to 33.9 months.
"We developed a mathematical model that describes the dynamics of the patient group with renal disease and superimposes a system that maximizes length and quality of life," explains Prof. Lawrence M. Wein of MIT, a co-author. "The model also minimizes inequity in waiting time and inequity in the likelihood of transplantation.
"Our model leads us to propose a new policy that assigns priorities using a mixture of efficiency points and equity points that are similar to the one used by UNOS. But we add a larger set of historical information about the patient and donor characteristics and their relationship to chance of a successful transplant. We also add points to reduce disparities between different groups." Using the proposed operations research system, when a new cadaveric kidney becomes available, a statistical model computes a health benefits score for each patient. This score takes into consideration both the patient and organ characteristics used by UNOS, as well as newly added factors that include prior transplants, body size, gender, and race. The health benefits score is higher for those patients that are most likely to gain maximum benefit from the organ. The score is then adjusted so that patients who repeatedly score low on the health benefits scale can gain equal access to transplantation.
The study, "Dynamic All
Contact: Barry List
Institute for Operations Research and the Management Sciences