The Lung Allocation Score Remains Inequitable for Patients with Pulmonary Arterial Hypertension, Even after the 2015 Revision

Abstract

Rationale: The lung allocation score (LAS) was revised in 2015 to improve waiting list mortality and rate of transplant for patients with pulmonary arterial hypertension (PAH). Objectives: We sought to determine if the 2015 revision achieved its intended goals. Methods: Using the Standard Transplant Analysis and Research file, we assessed the impact of the 2015 LAS revision by comparing the pre- and postrevision eras. Registrants were divided into the LAS diagnostic categories: group A-chronic obstructive pulmonary disease; group B-pulmonary arterial hypertension; group C-cystic fibrosis; and group D-interstitial lung disease. Competing risk regressions were used to assess the two mutually exclusive competing risks of waiting list death and transplant. Cumulative incidence plots were created to visually inspect risks. Measurements and Main Results: The LAS at organ matching increased by 14.2 points for registrants with PAH after the 2015 LAS revision, the greatest increase among diagnostic categories (other LAS categories: Δ, -0.9 to +2.8 points). Before the revision, registrants with PAH had the highest risk of death and lowest likelihood of transplant. After the 2015 revision, registrants with PAH still had the highest risk of death, now similar to those with interstitial lung disease, and the lowest rate of transplant, now similar to those with chronic obstructive pulmonary disease. Conclusions: Although the 2015 LAS revision improved access to transplant and reduced the risk of waitlist death for patients with PAH, it did not go far enough. Significant differences in waitlist mortality and likelihood of transplant persist.

Keywords: equity; lung allocation score; lung transplantation; pulmonary arterial hypertension.

Figure 1.

Cumulative incidence of waitlist death in (A) the whole cohort, (B) lung allocation score (LAS) category B–PAH, (C) LAS category A–COPD, (D) LAS category C–CF, and (E) LAS category D–ILD, stratified by era. Black lines indicate before 2015 LAS revision. Orange lines indicate after 2015 LAS revision. Log-rank test was performed to assess for statistical significance. CF = cystic fibrosis; COPD = chronic obstructive pulmonary disease; ILD = interstitial lung disease; PAH = pulmonary arterial hypertension.

Figure 2.

Cumulative incidence of transplantation in (A) the whole cohort; (B) lung allocation score (LAS) category B–PAH, (C) LAS category A–COPD, (D) LAS category C–CF, and (E) LAS category D–ILD, stratified by era. Black lines indicate pre-2015 LAS revision. Orange lines indicate post-2015 LAS revision. Log-rank test was performed to assess for statistical significance. For definition of abbreviations, see Figure 1.

Figure 3.

Cumulative incidence of (A) waitlist death, and (B) transplant before the 2015 lung allocation score (LAS) revision stratified by LAS category. Cumulative incidence of (C) waitlist death, and (D) transplant after the 2015 LAS revision stratified by LAS category. Purple lines denote LAS category B–PAH. Red lines indicate LAS category A–COPD. Green lines indicate LAS category C–CF. Blue lines indicate LAS category D–ILD. Log-rank test performed to assess for statistical significance. For definition of abbreviations, see Figure 1.

Figure 4.

Kaplan-Meier plot of post-transplant survival (A) before the 2015 lung allocation score (LAS) revision stratified by LAS category, and (B) after the 2015 LAS revision stratified by LAS category. Purple lines denote LAS category B–PAH. Red lines indicate LAS category A–COPD. Green lines indicate LAS category C–CF. Blue lines indicate LAS category D–ILD. Log-rank test performed to assess for statistical significance. For definition of abbreviations, see Figure 1.