Mitigating geographic disparities not enough

Sex-based inequities in access to liver transplants won’t necessarily be solved by just enacting policies designed to mitigate geographic disparities in liver allocations.

In fact, according to researchers, a more comprehensive approach is needed — one that addresses other aspects of the allocation system that disadvantage women, such as the inability of MELD (Model for End-stage Liver Disease) scores to accurately estimate the extent of disease severity in women.

In a retrospective cohort study, Jayme E. Locke, MD, MPH, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, Birmingham School of Medicine, and colleagues found that laboratory and MELD scores, as well as candidate anthropometric and liver measures, were strongly associated with disparities between men and women.

The study was published in JAMA Surgery.

The MELD score-based liver allocation system was adopted in 2002 as a metric for identifying patients at highest risk of death within 90 days of being placed on a transplant wait list. However, as Locke and colleagues pointed out, differences in local organ supply in demand have created geographical disparities in this allocation system.

Furthermore, they wrote, “discussions surrounding equity in allocation require critical assumptions to be met, including that the MELD score accurately defines disease severity and patients prioritized as the sickest actually receive the liver transplant.”

In this study, Locke and colleagues wanted to quantify sex disparities in wait list mortality and deceased donor liver transplant (DDLT) associated not only with geographic characteristics, but with clinical characteristics as well.

The study used data from 81,357 adults on the Organ Procurement and Transplant Network liver-only transplant waiting list from June 18, 2013, through March 1, 2018. Of these study subjects, 36.1% were women (mean age, 54.7 years), and 63.9% were men (mean age 55.7 years).

Locke and colleagues found that after weighting by geographic (United Network for Organ Sharing) region, women had 11.1% greater risk of wait list mortality compared with men (adjusted hazard ratio, 1.11; 95% CI, 1.06-1.17), representing a 22.8% increase in the disparity between female sex and wait list mortality. There was a statistically insignificant 3.9% increase in the disparity between female sex and DDLT.

However, while geographic location had a strong association with increased disparities in wait list mortality, Lock and colleagues found that candidate anthropometric and liver measurements, as well as laboratory MELD scores, had the strongest associations (125.8% and 50.1% increases in disparities among women, respectively).

And, while the increased disparity among women in DDLT was not statistically significant, anthropometric and liver measurements and MELD scores were associated with 49% and 10% increases, respectively.

“Although geographic factors matter, examining geographic access alone may be insufficient,” Locke and colleagues wrote. “We believe that efforts should simultaneously focus on ensuring that the definition of medical urgency, the MELD score, is equitable and that those who are prioritized for transplant, even those with small body stature, actually receive the transplant.”

In a commentary accompanying the study, Willscott E. Naugler, MD, and Susan L. Orloff, MD, both of Oregon Health and Science University, warned that simply making changes to the MELD score will not fix certain realities. For example, they noted that under the current allocation system women of smaller stature are bypassed when the donor liver is large.

There are simple solutions to these kinds of problems, they argued, but in reality, different cultural biases may be preventing their implementation. For example, they pointed to a study that showed that women, due to their role as traditional family caretakers, may end up declining access to a transplant, even when one is available.

“These realities cannot be fixed with changes to the MELD score, and we must be mindful not to let such notions distract from the essential hard work of creating long-lasting cultural changes that underpin a true path forward,” they wrote.

And in an accompanying opinion piece, Elizabeth C. Verna, MD, MS Center for Liver Disease and Transplantation, Columbia University Irving Medical Center, and Jennifer C. Lai, MD, MBA Department of Medicine, Division of Gastroenterology & Hepatology, University of California San Francisco, argued that changes in policy changes “to diminish the effect of this sex-based disparity on the chances of receiving a transplant could and should be prioritized and implemented to correct these unforeseen consequences of allocation rules.”

For example, eGFR for serum creatinine levels as the measure of kidney function in a MELD-based allocation score would have a rapid effect on the sex-based disparity in waiting list mortality, they suggested, while changing the liver allocation system to allow women of small stature access to pediatric donor livers once the pediatric waiting list is exhausted could mitigate disparities in waiting list outcomes.

“It is now time to move the debate from ongoing documentation of the disparity to discussing which concrete changes should be pursued first and how success will be measured,” Verna and Lai concluded.

  1. Sex-based inequities in access to liver transplants can’t be reduced by addressing geographic disparities alone.

  2. A much more comprehensive approach is needed that includes revising MELD (Model for End-stage Liver Disease) scores so they accurately estimate the extent of disease severity in women.

Michael Bassett, Contributing Writer, BreakingMED™

Locke reported receiving personal fees from Sanofi and Hansa Medical outside the submitted work.

Verna reports a grant from Salix Pharmaceuticals and is on the advisory board for Gilead Sciences outside the submitted work. Lai reports personal fees and other support (consulting and research support) from Axcella Health, personal fees (advisory board and consulting) from BioMarin, personal fees (advisory board and consulting) from Ambys Medicines, other (research support) from Pliant Therapeutics, other (research support) from Genentech, and grants from the National Institutes of Health outside the submitted work.

Cat ID: 636

Topic ID: 630,636,636,730,473,192,925,312