Improved Access to Lung Transplantation Among Adolescents After Introduction of the Lung Allocation Score

Abstract

SESSION TITLE: Pediatric Pulmonary SESSION TYPE: Original Investigation Slide PRESENTED ON: Tuesday, October 25, 2016 at 02:45 PM - 04:15 PM PURPOSE: The Lung Allocation Score (LAS) was introduced in May 2005 to allocate donor lungs to lung transplant (LTx) candidates ages 12 years and older on the basis of transplant urgency, while lung allocation for patients <12 years old remained dependent on waiting time. Effects of LAS implementation on outcomes in pediatric LTx candidates are unclear. METHODS: The United Network for Organ Sharing registry was queried to identify first-time LTx candidates ages 0-17 years listed between 1995-2015. Waitlist outcomes included transplantation, mortality, and removal due to deteriorating condition. One-year survival was assessed post-transplant. Difference-in-difference models were fitted to estimate the influence of LAS implementation on outcomes of adolescents (ages 12-17) compared to children (ages 0-11). Competing-risks regression was used for waitlist outcomes and Cox proportional hazards regression was used for 1-year post-transplant survival. Trends in the LAS among adolescents listed after LAS implementation were described using least-squares regression. RESULTS: There were 1,287 adolescents (495 listed after LAS implementation) and 981 children (370 listed after LAS implementation) who were listed for LTx since 1995 and selected for analysis. The most common waitlist outcome was transplantation (47% of adolescents and 45% of children), whereas 17% of children and 16% of adolescents died on the waitlist. In competing-risks regression, LAS implementation increased the hazard of transplantation for adolescent candidates (HR=2.21; 95% CI=1.89, 2.58; p<0.001), and the interaction between adolescent age and transplant era determined this improvement was greater for adolescents than for children (p<0.001). There was no significant change in waitlist mortality hazard among adolescents when comparing the LAS to the pre-LAS era (HR=0.79; 95% CI=0.59, 1.06; p=0.119). Among LTx recipients (593 adolescents, 435 children), Cox analysis of 1-year mortality demonstrated marginally significant improvement in survival for adolescents after LAS implementation (HR=0.68; 95% CI=0.46, 1.03; p=0.066), and no significant difference in this effect between children and adolescents (p=0.596). Since LAS implementation, adolescents’ LAS at transplantation has trended upwards by 0.78 points (95% CI=0.09, 1.46; p=0.027) each year. CONCLUSIONS: Relative to children <12 years old, LAS implementation improved access to LTx for adolescents ages 12-17, although LAS-era improvements in post-transplant outcomes among adolescents were modest. The latter may be attributable to a trend towards transplanting adolescents with higher transplant urgency in the recent era. CLINICAL IMPLICATIONS: Donor allocation for LTx in children remains to be a controversial topic in the United States. The LAS system appears to have made a positive impact on LTx in adolescent candidates since implementation. DISCLOSURE: The following authors have nothing to disclose: Don Hayes, Jr., Joseph Tobias, Dmitry Tumin No Product/Research Disclosure Information