Research Feature: Impact of living donation on women’s access to liver transplantation
Did you know?
- Living liver donations accounted for 21% (1 in 5) of the estimated 36,000 liver transplants performed in WHO member countries in 2019. (Source)
- In Canada, 1 in every 8 liver transplants is made possible by a living liver donor. (Source)
- Two-thirds of Canadian living donors are women. (Source)
In August, Dr. Mamatha Bhat and team published their latest work Sex Disparity in Liver Transplant and Access to Living Donation in JAMA Surgery. It is known that women are disadvantaged in their access to deceased donor liver transplants, and their study examined whether living donation could help remedy this inequity. We caught up with Mamatha to find out more.
How do you think the research will advance the field?
The MELD Na score was transformational in decreasing overall waitlist mortality. However, over time, we have realized that there are certain subgroups that are disadvantaged by this score. For women, the disadvantage is multifactorial. Firstly, the MELD Na in women appears to underrepresent the degree of illness. Specifically, the creatinine in women tends to be lower due to lower muscle mass, and the sodium is also underreflected. Women with cholestatic liver disease such as PBC and PSC are also disadvantaged, due to the bilirubin being underweighted in the MELD Na score.
Beyond prioritization, organ allocation depends on the match between the donor and recipient liver. Most deceased donor organs are from male donors, which could be a disadvantage to women with smaller bodies. A study by Locket et al in JAMA Surgery, 2020 confirmed that women were 14.4% less likely to receive a deceased organ compared to men, having accounted for geographic location, MELD score, and candidate anthropometric and liver measurements.
In our study, we confirmed that living donor liver transplantation is helpful to all patients (both women and men) on the waiting list, regardless of their clinical characteristics. Beyond this, we discovered that as a program performing living donor liver transplants, we can alleviate sex disparity on the waiting list. In fact, using competing risk analysis, we found that women benefited from access to living donor liver transplantation 1.38 times more than men.
Where should the research go from here?
Various studies have looked into how sex disparity on the waiting list could be rectified. However, none of the adjustments for factors such as GFR and liver volume have been able to rectify this disparity. Therefore, this is a very complex problem with no simple solution, given the number of variables involved and dynamics on the waiting list.
I feel that we should be developing a new prioritization and decreased donor organ allocation system that is responsive to the evolving clinical characteristics of waitlisted patients. It is likely that the optimal prioritization would vary based on the unique considerations of each jurisdiction in terms of indication for transplant and supply:demand mismatch. Until such time as we develop a more optimal and equitable prioritization and allocation system, living donation could be considered particularly if there is a substantial mismatch between organ supply and demand in a particular jurisdiction.
The CDTRP is proud to be supporting Dr. Bhat’s work through 2016 and 2018 Research Innovation Grants, funded in partnership with University Health Network.
You can find Mamatha on Twitter @MamathaBhat3 and as co-lead of CDTRP Research Theme 4: Tailor an Optimal Immune System for Each Patient.