The context you need, when you need it

When news breaks, you need to understand what actually matters — and what to do about it. At Vox, our mission to help you make sense of the world has never been more vital. But we can’t do it on our own.

We rely on readers like you to fund our journalism. Will you support our work and become a Vox Member today?

The liver transplant system tried to fix its sex bias. Did it work?

The algorithm that ranks candidates just got an update and the results are in.

In theory, getting a donor liver in the United States when you need one should be an extremely equitable process: The sickest patients with the greatest chance to benefit from a donated organ should jump to the front of the line regardless of their gender, race, or other factors.

But in practice, things look quite different.

One study from 2020 showed that women were 8.6 percent more likely than men to die waiting for a liver transplant and 14.4 percent less likely to receive a deceased donor liver transplant compared to men. That gap may not seem enormous, but it still represents a significant disparity. As it turns out, it’s rooted in the very system that’s supposed to make the process fairer, a process that unintentionally ranks women lower on the waitlist for livers.

Explore the big, complicated problems the world faces and the most efficient ways to solve them. Sent twice a week.

The system in question is known as the Model for End-Stage Liver Disease (MELD). The scoring model has been used since 2002 to rank candidates on the waiting list based on how likely they are to survive without a liver transplant in the short term. The higher your score, the reasoning goes, the sicker you are and the more urgently you need a liver transplant.

One of the values used to calculate the score is creatinine — a waste product made by muscles as they break down proteins or other compounds to release energy. In medicine, the creatinine levels in your blood are used to determine how well your kidneys are functioning because they process and remove creatinine.

And this is where the system designed for equity gets a little less than equitable for some patients.

Creatinine levels are affected by muscle mass, and women typically have lower muscle mass than men. A man and woman experiencing the same level of kidney dysfunction will therefore have different levels of creatinine in the body. The MELD model doesn’t take this difference into account — and so lower levels of creatinine in a woman’s blood can make her seem healthier than she is, bumping her farther down the liver waiting list.

In 2023, Dr. Ray Kim, a transplant hepatologist at Mayo Clinic in Arizona who developed the original system, debuted a new model called MELD 3.0. The model not only seeks to address the sex disparity in liver access but also improve the accuracy of scores for all patients. Among other changes, it takes into account the sex of the transplant candidate and uses it to adjust the MELD score by 1.33 points for women. This is meant to address the difference in creatinine levels between men and women and provide a more accurate understanding of how sick a female patient really is.

Simple fix, right? Even though MELD 3.0 took the sex disparity in liver access seriously and developed changes to combat it, early research on its efficacy found that even this new and improved system hasn’t yet brought men and women to parity on the liver waitlist.

And the problem may lie less with what MELD 3.0 did than with what it did not do, prompting the question: Are we focusing on the wrong........

© Vox