Travel time disparities in access to liver transplantation in the United Kingdom: An argument for adding another center

External Validation of the United Kingdom Transplant Benefit Score in Australia and New Zealand

Introduction: In Australia and New Zealand, liver allocation is needs based (based on model for end-stage liver disease score). An alternative allocation system is a transplant benefit-based model. Transplant benefit is quantified by complex waitlist and transplant survival prediction models. Research Questions: To validate the UK transplant benefit score in an Australia and New Zealand population. Design: This study analyzed data on listings and transplants for chronic liver disease between 2009 and 2018, using the Australia and New Zealand Liver and Intestinal Transplant Registry. Excluded were variant syndromes, hepatocellular cancer, urgent listings, pediatric, living donor, and multi-organ listings and transplants. UK transplant benefit waitlist and transplant benefit score were calculated for listings and transplants, respectively. Outcomes were time to waitlist death and time to transplant failure. Calibration and discrimination were assessed with Kaplan-Meier analysis and C-statistics. Results: There were differences in the UK and Australia and New Zealand listing, transplant, and donor populations including older recipient age, higher recipient and donor body mass index, and higher incidence of hepatitis C in the Australia and New Zealand population. Waitlist scores were calculated for 2241 patients and transplant scores were calculated for 1755 patients. The waitlist model C-statistic at 5 years was 0.70 and the transplant model C-statistic was 0.56, with poor calibration of both models. Conclusion: The UK transplant benefit score model performed poorly, suggesting that UK benefit-based allocation would not improve overall outcomes in Australia and New Zealand. Generalizability of survival prediction models was limited by differences in transplant populations and practices.

Area deprivation is associated with poorer overall survival in children with acute lymphoblastic leukemia

BACKGROUND

Few studies have evaluated social determinants of outcomes disparities for children with acute lymphoblastic leukemia (ALL). We investigated the association of area deprivation index (ADI), a measure of neighborhood socioeconomic disadvantage, with overall survival (OS) among children and adolescents with ALL.

PROCEDURE

We obtained demographic and clinical data, geocoded addresses at diagnosis, and vital status on all Texas children diagnosed with ALL from 1995 to 2011 (N = 4104). Using the US Census Bureau 2010 geography, we computed ADI scores for all census tracts in Texas and grouped the tracts into quartiles: least, third-most, second-most, and most disadvantaged. We mapped children to ADI quartiles based on residence at diagnosis, and estimated OS using Cox regression adjusting for sex, race/ethnicity, age, and metropolitan/nonmetropolitan residence.

RESULTS

Five-year OS ranged from 89% (95% confidence interval [CI] 87-91%) for children in the least disadvantaged tracts to 79% (95% CI 76-81%) for children in the most disadvantaged tracts (P = 4E-7). An elevated hazard ratio (HR) for death was observed for children in the most disadvantaged tracts (HR 1.57, 95% CI 1.23-2.00), and trends toward increased mortality were observed in the third-most and second-most disadvantaged tracts (HR 1.23, 95% CI 0.97-1.57 and HR 1.27, 95% CI 0.99-1.62, respectively). In stratified analyses, area disadvantage was more strongly associated with OS in males than females.

CONCLUSIONS

Neighborhood socioeconomic disadvantage is associated with inferior OS in this analysis of over 4100 children with ALL, highlighting the substantial contributions of social-environmental factors to childhood cancer survival. This association was stronger in males than females.