Gender Disparity in Lung Transplantation in the Pre- and Post–Composite Allocation Score System

Abstract

Background This study evaluated access to lung transplantation and outcomes in male and female candidates and examined the impact of recent changes to the Composite Allocation Score (CAS) system. Methods The United Network for Organ Sharing database was queried for all adult candidates listed for isolated lung transplantation from March 2022 to March 2024. Two distinct eras (era 1 and era 2) were defined on the basis of the implementation date of the CAS system. Each era was stratified by candidate gender (female vs male). Multivariable competing risk regression analysis was used to compare the transplantation rates and waitlist mortality; 6-month posttransplant survival was analyzed by the Kaplan-Meier method. Results A total of 6878 patients were included in the analysis, with era 1 comprising 3311 patients (40.7% female) and era 2 comprising 3567 patients (42.7% female). In era 1, women experienced a lower transplant rate than men (adjusted subhazard ratio [aSHR], 0.68; P < .001) but had similar waitlist mortality (aSHR, 1.00; P = .98) and posttransplant survival (91.9% vs 93.4%; P = .16). In era 2, female candidates still had a lower transplant rate compared with their male counterparts (aSHR, 0.84; P = .003) and continued to have similar waitlist mortality (aSHR, 1.16; P = .45) and posttransplant survival (92.8% vs 94.0%; P = .24). Conclusions Whereas the CAS system improved lung transplantation rates for female candidates, disparities in lung organ access based on gender persist. These findings underscore the need for ongoing evaluation and potential modification of allocation policies and practices.