Gender Disparity in Waitlist Outcomes of Lung Transplantation in the Composite Allocation Score System

P. D.. Cho¹, J. P.. White², S. McKay², H. Zappacosta², D. Sayah², A. Ardehali^3
1Drexel University College of Medicine, Wyomissing, Pennsylvania ²David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California ³UCLA Medical Center, Los Angeles, California

Purpose: There has been a growing concern regarding reduced lung organ access and inferior outcomes of lung transplantation (LT) in women when compared to men. This study evaluates the impact of recent lung allocation policy changes on gender-based disparities in lung transplantation (LT) outcomes.

Methods: This study analyzed data from the United Network for Organ Sharing database, encompassing adult recipients of isolated LT from February 2022 to March 2024. Two distinct eras (Era 1 and Era 2) were defined based on the implementation date of the Composite Allocation Score (CAS) system, on March 9, 2023. Each era was stratified by recipient sex (male vs female). Multivariable competing risk regression analysis was utilized to assess changes in transplantation rates and waitlist mortality, while 6-month post-transplant survival was analyzed using the Kaplan-Meier method.

Results: A total of 7,046 patients were included in the analysis, with Era 1 comprising 3,652 patients (42.5% women) and Era 2 comprising 3,394 patients (40.8% women). In Era 2, women and men had similar CAS (32.0 vs 31.73, p=0.11), but women experienced longer waitlist durations (25 vs 17 days, p< 0.001). Women in Era 2 had a lower likelihood of undergoing LT compared to men (Figure), despite similar waitlist mortality (adjusted Sub-Hazard Ratio (aSHR): 0.72; 95% Confidence Interval (CI): 0.51-1.01, p=0.07). However, women in Era 2 had a significantly higher transplantation rate compared to women in Era 1 (aSHR: 1.88; 95% CI: 1.70-2.07, p< 0.001) (Table). No significant difference in 6-month survival post-transplant was observed between women and men in Era 2 (89% vs 90%, p=0.69).

Conclusion: While the updated allocation system improved LT rates for female recipients, disparities in lung organ access based on gender persist. These findings underscore the need for ongoing evaluation and potential modification of allocation policies to ensure equitable access to LT for all eligible patients.

Identify the source of the funding for this research project: None