Equity in organ transplantation: Are we there yet?

The Organ Procurement and Transplantation Network (OPTN) released its latest policy updates on July 13, 2023, that aimed to improve equity in liver allocation. This update improved the model for end-stage liver disease (MELD) scoring system by incorporating additional variables (albumin and sex), updating coefficients for existing variables, introducing interaction terms and lowering the maximum creatinine value to 3.0 mg/dL from 4.0.

The most notable of these changes was to add sex as a variable used in the model. The new MELD score aims to resolve the disparities in transplant rate and waitlist mortality for female patients as described on American Journal of Transplantation (AJT) more than 10 years ago. Using the previous MELD score, women were 19% more likely to die on the waiting list as compared to men. In addition, females had a 14% lower transplant rate than males with similar MELD score and other clinical factors. While the new MELD has improved, there are reasons to be skeptical about whether it should be the ultimate model. Fortunately, the OPTN updates its prediction model using the most recent data at least every 5 years.

Last July, the OPTN issued a new policy update to resolve racial disparities in kidney transplantation. This policy called for race to be removed from the formula to calculate Estimated Glomerular Filtration Rate (eGFR) for newly registered kidney transplant candidates. The inclusion of the race variable in eGFR calculations had shown to increase eGFR values by as much as 16% for Black individuals.

Overestimated eGFR values resulting from race adjustments had the potential to delay referral for kidney transplantation and the initiation of qualifying waiting time. In addition, the use of race adjustments in the calculation of eGFR had the potential to exacerbate existing disparities and negatively impact patient outcomes. In January 2023, the OPTN also published a new policy mandating transplant programs submit complete eGFR waiting time modifications for all affected candidates and inform all registered kidney candidates by Jan. 3, 2024.

Each organ is different and we should add/remove variables in the model for a specific organ based on rigorous scientific evidence. However, sex and race have been described in the literature as social determinants affecting transplantation inequities and have received the most attention from researchers, policy makers and the public. Black and female patients have been systemically disadvantaged when accessing the service. Further studies are needed to establish causal mechanisms leading to these disparities and evaluate tailored interventions to resolve them. Given all the ongoing changes in policies, I believe there is good momentum to get there. Organ transplant is a special service. There should not be any disparities in receiving it.

As a recent heart transplant said: “I know nothing about my new heart other than it has saved my life. My heart could be male or female. My heart might be Hispanic, Black, Native American, Indian or Caucasian… My experience as a heart transplant recipient brought home an essential truth to me: We are ALL part of one another. We are one humanity. Our physical parts are even interchangeable. We can – if we choose to – have a unified heartbeat despite our differences.”

By Dr. Anh Nguyen, Department of Pediatrics, Baylor College of Medicine.