Examining the Impact of Donor, Recipient Characteristics on Lung Transplant Mortality

Carli Lehr, MD, PhD

Credit: Cleveland Clinic

A recent study found that there are significant differences in organ transplant outcomes based on race and ethnicity, while socioeconomic status and region weren’t contributors to most of the observed differences in posttransplant outcomes.¹

“In this study, differential survival by race and ethnicity existed despite efforts to account for variation by socioeconomic position and region, a finding that highlights the presence of a complex social reality that warrants continued study to improve equity in posttransplant outcomes,” investigators wrote.

Analyzing Mediators of Posttransplant Outcome

Carli Lehr, MD, PhD, Cleveland Clinic, and a team of investigators conducted the cohort study to evaluate the role of donor and recipient socioeconomic position and region as a mediator of the observed racial and ethnic differences previously observed in patient survival following a transplant.

Patients who underwent a lung transplant and the donors who provided the organ for transplant between September 2011 -  September 2021 according to the US transplant registry were included in the analysis. Race and ethnicity information and a zip code tabulation area–defined area deprivation index (ADI) were collected on 19,504 participants from the registry.

The study used univariable and multivariable Cox proportional hazards regression to assess the association between donor and recipient race, ADI, and posttransplant survival. The Kaplan-Meier method was used to estimate survival rates based on donor and recipient ADI.

Generalized linear models were fit by race, and mediation analysis was performed. The study also used Bayesian conditional autoregressive Poisson rate models to analyze variation in posttransplant mortality and compared them according to ratios of mortality rates to the national average.

Disparities in Lung Transplant Outcomes

Findings showed the median age of the donors was 33 years, and the median age of recipients was 60 years. Donors were primarily non-Hispanic White (61.2%) and recipients were also predominantly non-Hispanic White (78.8%).

Recipients identifying as non-Hispanic White had the highest proportion of individuals residing in the lowest ADI quintile neighborhoods, while recipients identifying as non-Hispanic Black race and Hispanic ethnicity had the highest proportion of individuals residing in the highest ADI quintile neighborhoods.

According to the results, socioeconomic position and region of residence didn’t explain most of the differences in posttransplant outcomes among racial and ethnic groups. Investigators stated this could be due to the highly selected nature of the pretransplant population.

However, the study did find that ADI mediated 4.1% of the survival difference between non-Hispanic Black and Hispanic recipients. The spatial analysis revealed that the increased risk of posttransplant death among non-Hispanic Black recipients may be associated with the region of residence.

Recipients who received organs from donors residing in the least-resourced neighborhoods and who were of non-Hispanic Black or Asian or Pacific Islander race had an increased risk for posttransplant mortality. Regional associations were observed, with an increased risk of posttransplant mortality for recipients who received organs from the Northeast in the full conditional autoregressive model.

Although, investigators reported the conditional autoregressive model that used fixed effects for region alone found recipients from the South were at a greater risk for poor posttransplant outcomes, indicating that the increased risk of posttransplant death among non-Hispanic Black recipients may be related to region.

The findings suggest that addressing racial and ethnic disparities in organ transplant outcomes will require a multifaceted approach that considers a range of factors, including socioeconomic position, geographic location, and other potential mediating effects.

The team stated these data support the need for further research to identify other potentially mediating factors contributing to inequity in posttransplant survival, and have important implications for policymakers, healthcare providers, and advocates working to improve equity in access to life-saving organ transplants.

References:

1. Lehr CJ, Valapour M, Gunsalus PR, et al. Association of Socioeconomic Position With Racial and Ethnic Disparities in Survival After Lung Transplant. JAMA Netw Open. 2023;6(4):e238306. doi:10.1001/jamanetworkopen.2023.8306