Racial, ethnic, and sex disparities in lung transplant waitlist outcomes before and after composite allocation score implementation.

Introduction: We aimed to evaluate if known racial, ethnic, and sex disparities in lung transplant waitlist outcomes with the Lung Allocation Score (LAS) persist with implementation of the Composite Allocation Score (CAS). Methods: We performed a retrospective cohort study of the Scientific Registry of Transplant Recipients (SRTR) database, examining waitlist outcomes of all adult patients listed for lung transplantation in the United States from January 2018 to March 2024, comparing patients listed in the LAS (1/1/2018-9/9/2022) or CAS (3/9/23-3/24/24) eras. Results: Black candidates had a lower likelihood of transplantation (LAS sHR: 0.85, 95% CI: 0.79-0.91, p<0.001; CAS sHR: 0.81, 0.71-0.93, p=0.002) compared to White candidates in both eras, and a greater likelihood of waitlist removal (sHR: 2.31, 1.35-3.95, p=0.003) in the CAS era. Female candidates had lower rates of transplantation compared to male candidates in both eras (LAS sHR: 0.75, 0.71-0.80, p<0.001; CAS sHR: 0.88, 0.79-0.98, p=0.017). There were no significant differences in extracorporeal membrane oxygenation (ECMO) or mechanical ventilation while listed between race/ethnicity in the CAS era. Female candidates had lower odds of ECMO in both eras (LAS OR: 0.74, CI: 0.58-0.95, p=0.019; CAS OR: 0.53, 0.30-0.96, p=0.037). Black candidates had a greater hazard of waitlist removal due to "other" reasons compared to White candidates in both eras (LAS sHR: 1.75, 1.27-2.42, p<0.001; CAS sHR: 2.06, 1.17-3.61, p=0.013). Conclusion: Disparities in lung transplant waitlist outcomes are improved but persist in the CAS era. These disparities warrant further investigation into ways to provide more equitable access to lung transplantation.