Lung Composite Allocation Score System Cuts Waiting-List Mortality

MONDAY, Jan. 9, 2023 (HealthDay News) — The new Composite Allocation Score (CAS) system developed to improve equity in organ allocation by eliminating geographical barriers and prioritizing candidates’ medical needs results in a decrease in waiting-list deaths among lung transplant candidates, according to a study published in the December issue of the American Journal of Transplantation.

Maryam Valapour, M.D., from the Cleveland Clinic, and colleagues compared discrete CAS scenarios to the current concentric circle-based allocation system to assess their potential effects on the U.S. lung transplantation system. Using data from individuals on the lung transplant waiting list from Jan. 1, 2018, through Dec. 31, 2019, six alternative CAS scenarios were compared over 10 simulations.

The researchers observed a decrease of 36 to 47 percent in waiting-list deaths across scenarios, with larger decreases in deaths at lower placement efficiency weight and higher weighting of the waiting-list outcomes. More transplants occurred in individuals with the highest expected posttransplant survival when waiting-list outcomes were equally weighted to posttransplant outcomes. Improved overall measures of equity were seen for all CAS scenarios compared with the current Lung Allocation Score system, including reduced waiting-list deaths, resulting in similar survival posttransplant.

“The importance of removing the geographical barrier can’t be overstated here,” Valapour said in a statement. “The Composite Allocation Score system’s goal of making access to lung transplant more equitable for all candidates in the United States will help reduce waitlist mortality and we hope will even improve posttransplant survival over time.”