Saturday, May 18, 2019

Yale SOM celebrates Vahideh Manshadi on the benefits of scale in kidney exchange

In Yale Insights (from Yale SOM):

Kidney Exchange Registries Should Collaborate to Save More Lives
VAHIDEH MANSHADI

"The results were surprising, says Manshadi. “We didn’t find any evidence that higher-frequency match runs were reducing the overall number of transplants by depleting the pool of potential donors. The total number of transplants remained stable.”

"What the researchers did find, however, was an unexpectedly high number of patients in both programs whose antibodies made them hard to match—what are called sensitized patients.

“The majority of patients in these programs are sensitized,” Manshadi says. “These patients have such high levels of antibodies in their blood that they are more likely to reject a donor organ. Frequent or infrequent matching will have little effect on them because it’s so much harder to find a donor whose kidney they can accept.”

"The best way of improving the outlook for these patients, says Manshadi, is to ensure they are prioritized when searching for matches. That, and find new ways of increasing—and diversifying—the number and range of donors coming into exchange programs. "
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And here's the original paper:

Effect of match‐run frequencies on the number of transplants and waiting times in kidney exchange
Itai Ashlagi  Adam Bingaman  Maximilien Burq  Vahideh Manshadi  David Gamarnik  Cathi Murphey  Alvin E. Roth  Marc L. Melcher  Michael A. Rees, American Journal of Transplantation, Volume18, Issue5, May 2018, Pages 1177-1186
First published: 31 October 2017 https://doi.org/10.1111/ajt.14566

Abstract
Numerous kidney exchange (kidney paired donation [KPD]) registries in the United States have gradually shifted to high‐frequency match‐runs, raising the question of whether this harms the number of transplants. We conducted simulations using clinical data from 2 KPD registries—the Alliance for Paired Donation, which runs multihospital exchanges, and Methodist San Antonio, which runs single‐center exchanges—to study how the frequency of match‐runs impacts the number of transplants and the average waiting times. We simulate the options facing each of the 2 registries by repeated resampling from their historical pools of patient‐donor pairs and nondirected donors, with arrival and departure rates corresponding to the historical data. We find that longer intervals between match‐runs do not increase the total number of transplants, and that prioritizing highly sensitized patients is more effective than waiting longer between match‐runs for transplanting highly sensitized patients. While we do not find that frequent match‐runs result in fewer transplanted pairs, we do find that increasing arrival rates of new pairs improves both the fraction of transplanted pairs and waiting times.

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