Socioeconomic status does not explain racial disparities in survival after transplant

Key takeaways:

• Accounting for area deprivation index did not improve racial disparities in survival after transplantation among donors and recipients.
• Black vs. white recipients had worse survival.

Increased mortality following lung transplantation was found among both Black recipients and those who received a lung from a Black donor, and this disparity could not be explained by socioeconomic status, according to study results.

“The finding of increased post-transplant risk for recipients of donors of non-Hispanic Black race/ethnicity and those of the lowest area deprivation index (ADI) quintile were surprising to us,” Carli J. Lehr, MD, PhD, pulmonologist at Cleveland Clinic, told Healio. “This finding suggests that perhaps the biologic embodiment of social adversity and associated injustices that occur across the life course of racially minoritized individuals contribute to health outcomes of not only the donor but the recipient of their donated lungs. This can be further compounded when considering adverse life experiences of both a donor and recipient when evaluating post-transplant outcomes.”

In a cohort study published in JAMA Network Open, Lehr and colleagues analyzed 19,504 lung transplant donor (median age, 33 years) and recipient pairs (median age, 60 years) from September 2011 to September 2021 to see if socioeconomic status and region of residence could explain racial disparities in survival following transplantation.

The socioeconomic conditions of the donors and recipients’ regions were found through ADI, which combines 17 data points from the U.S. census related to income, education, employment and housing. The scoring scale ranges from 0 to 100, with a lower score representing most resourced areas (quintile 1) and a higher score representing least resourced (quintile 5).

Through Kaplan-Meier analysis, researchers assessed how survival differed according to individuals’ ADI scores. They also utilized Cox proportional hazards regression to determine the relationship between race/ethnicity, ADI and survival.

Findings

Of the total cohort, most donors were non-Hispanic white (61.2%), followed by Black (18.8%) and Hispanic (16%) individuals. Similar race prevalence was found in the lung transplant recipients, with more non-Hispanic white individuals (78.8%) than Black (9.5%) and Hispanic (8.8%) individuals.

In ADI quintile 5 areas, researchers found more Black and Hispanic individuals than white individuals, whereas more white individuals lived in ADI quintile 1 areas.

When evaluating only one variable, the donor demographic of Black race was linked to a higher risk for death in recipients following transplantation (HR = 1.23; 95% CI, 1.16-1.31), and this risk remained elevated after adjusting for donor race, ethnicity and ADI. For those who had a donor living in ADI quintile 5, researchers did observe a slightly lower risk for death after accounting for race/ethnicity, but it still demonstrated a heightened risk (14% vs. 8%), according to researchers.

Comparable findings were observed in Kaplan-Meier analysis, with higher recipient mortality linked to having a donor who lived in the highest ADI quintile (P = .003) or of Black or Hispanic race.

When evaluating outcomes in recipients based on their racial/ethnic group, researchers further found a link between Black race and mortality, with Black individuals facing greater risks for mortality than Hispanic individuals by 18% (95% CI, 3%-36%) and white individuals by 11% (95% CI, 1%-22%). After adjusting for race, ethnicity and ADI, this risk remained.

Further, death rates did not differ significantly between white and Hispanic recipients, according to researchers.

Between Black and white recipients, researchers found no explanation of disparities in survival when factoring in ADI. However, when evaluating survival differences among Black and Hispanic individuals who received a transplant, ADI did slightly mediate this difference (4.1%; P = .006).

Survival rates were comparable in the five ADI quintiles of recipients; however, the number of deaths by race and ethnicity was different, with higher death rates per 100 person-years observed in Black recipients than white or Hispanic recipients in Kaplan-Meier analysis.

In spatial analysis, excluding donor and recipient region yielded the risk factor of Black recipient race, and this signals that region might have a part in the higher mortality risk in Black recipients, according to researchers.

“The findings of this study highlight two key areas in transplant medicine that deserve more attention,” Lehr told Healio. “First, the population of individuals who ultimately are able to access transplant is highly selected and as highlighted in a recent National Academies of Sciences Engineering and Medicine report, ‘An individual’s chance of referral for transplant evaluation, being added to the waiting list, and receiving a transplant varies greatly based on race and ethnicity, gender, geographic location, socioeconomic status, disability status, and immigration status.’ Second, despite this clinically homogenous residual cohort that is more insulated from social and economic stressors compared with the general end-stage lung disease population, racial differences in post-transplant outcomes still exist and must be studied further to achieve improved equity in the U.S. transplant system.”

Implications, future studies

Since systemic racism effects many patients, these results are extremely relevant for the everyday clinician, Lehr told Healio.

“It is important for clinicians to be aware of the impact that systemic racism has in determining a patient’s life experiences, as well as its impact on chronic diseases,” Lehr told Healio. “Furthermore, it is essential to be conscious of our own biases and how these may impact our patients. Finally, efforts focusing on increasing representation of racially minoritized individuals, cultural sensitivity training and advocacy efforts within medicine must continue to make progress for our patients.”

In addition to these messages for clinicians, Lehr said further analysis on disparities is needed.

“Future studies should focus on the impact of the effects of pulmonary and other chronic comorbidities on disparities and capture environmental factors that are not adequately captured by the ADI,” she told Healio.