(147) Lung transplant waitlist disparities for children with cystic fibrosis

Background: With no previous research evaluating whether disparities influence outcomes for children with cystic fibrosis (CwCF) on the waitlist for lung transplant (LTx) or who undergo LTx in the United States, we explored this important question using a national registry. We examined whether survival differences exist between White non-Hispanic (WNH) and non-White (NW) (Black/Hispanic/Asian/Other) CwCF either on the waitlist for LTx or who underwent LTx.

Methods: The United Network for Organ Sharing (UNOS) Registry was queried for CwCF (< 18 years-of-age) in the modern era who were waitlisted for or underwent LTx between January 1, 2000 and December 31, 2021. Chi-square and non-parametric median tests were used to compare categorical and continuous variables, respectively. Data is presented as median with interquartile range (IQR). Statistical significance was achieved at a p-value < 0.05.

Results: A total of 828 CwCF were placed on the waitlist for LTx with 660 in the WNH cohort and 198 in the NW cohort. Comparing these two cohorts, WNH CwCF (N=660) were older (15 [12-16] years vs 14 [10.25-15] years, p< 0.001), taller (150 [138-157.5] cm vs 146.6 [128.8-154.9] cm, p=0.02), and on the waitlist longer (180 [41-540.25] days vs 109 [31-349] days, p=0.001). In addition, there was no difference in sex, body mass index (BMI), weight, lung allocation score, and mean pulmonary artery pressure (mPAP) between the two cohorts. Compared to WNH, our analysis identified that NW CwCF had a significantly higher rate of dying on the waitlist or removal from it for deteriorating conditions 47 (27.9%) vs 123 (18.6%), p=0.007. Nonetheless, there was no difference between the two cohorts for removal due to undergoing LTx or improved condition (WNH vs NW: 455 (68.9%) vs 104 (61.9%), p=0.08) and Other/unknown (WNH vs NW: 82 (12.4%) vs17 (10.1%), p=0.4). The Figure shows Kaplan-Meier survival curves for WNH and NW CwCF on the waitlist for LTx (Left Panel) and post-LTx (Right panel). Cox proportional model multivariate analysis for the key clinical variables (age, height, weight, BMI, LAS, and mPAP) for NW versus WNH CwCF did not identify significant confounders contributing to waitlist survival. There was no difference in post-LTx survival between CwCF who were NW (mean survival: 3099 95%CI (2304-3876) days) versus WNH (mean survival: 3055, 95%CI (2727-3393) days) (p=0.8) (Right panel). During this same time period, there were no disparities found in waitlist outcomes for adults with CF who were WNH vs NW (p=0.3).

Conclusions: A significant LTx waitlist disparity for NW CwCF was identified. Despite advancements in cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy greatly impacting the pediatric CF population and reducing the need for LTx in WNH CwCF, we anticipate the need for LTx to continue in NW CwCF until specific discoveries can address the more common CFTR mutations in the NW CF population. Therefore, there is a pressing need to address the waitlist disparity in NW CwCF, given the impact of this issue.

Acknowledgements: This work was supported by the National Institute of Health R01HL142210 (AZ), R01HL151588 (AZ-MPI) and R01HL147957-01

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