Oct. 20, 2005 • Volume 14 Number 4

EXTRA Credit

Classic economic principles are literally a life-or-death matter in the work done by Prof. Tayfun Sonmez, a member of a team of economists that has developed a system for optimizing live donor kidney exchanges.

Sonmez and his colleagues utilize economic matching theory to match incompatible donor-patient pairs - in which each donor is unable to give a kidney to the intended recipient because of immunological unsuitability - with similarly incompatible pairs so that each patient can receive a kidney from a compatible donor. The transplants are done simultaneously so that each pair who donates a kidney also receives one.

The team's work has led to the establishment of a New England area kidney exchange clearinghouse, which is envisioned as the model for a national system that would shorten the wait time for kidney transplant patients and potentially save thousands of lives.

How do economists get involved in such a seemingly medical-scientific venture?

"Economics is basically a study of the efficient use of scarce resources," explains Sonmez, who joined the Boston College faculty this year after teaching at the University of Michigan and Koc University in his native Turkey. "It's a real life application of the economic principles of mechanism and market design."

Research that led to the computerized optimal kidney exchange proposal developed by Sonmez and his colleagues - Alvin Roth of Harvard University and Utku Unver of the University of Pittsburgh - was funded with three grants totaling $700,000 from the National Science Foundation. The initial results were published in the Quarterly Journal of Economics and American Economic Review Papers and Proceedings.

The economists' theory of optimizing kidney exchanges was accepted by the Renal Transplant Oversight Committee of New England in September, 2004. Over the following three months, five transplant matches were identified, and the idea has been embraced by Maryland's Johns Hopkins Hospital as well as transplant facilities in Ohio. Other transplant organizations across the nation are starting to show interest in both forming databases and in optimizing kidney exchanges, Sonmez says.

Sonmez hopes the research will help expand the database from its present two-way donor-recipient interactions to possible three-way exchanges, he says, significantly increasing the number of patients who could benefit from kidney transplant procedures.

"It's baby steps right now," he says. "But it's growing, and it's growing very fast. It is not only efficient, it does not suffer from an incentive issue."

Sonmez' research is available on-line at -Reid Oslin

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