Sex-based Differences and Comparative Predictive Value of MELD 3.0 in Simultaneous Liver-Kidney Transplantation Waitlist Outcomes After Standardization of Listing Criteria in the United States.

Background: Sex disparities in solid organ transplantation are well documented. Relative changes in sex-based outcome disparities after the 2017 standardization of simultaneous liver-kidney (SLK) listing criteria in the United States have not been reported. We hypothesized that this policy's objective measures of kidney dysfunction may differentially affect SLK patients by sex and that the use of MELD 3.0 in the SLK population might provide unique benefit to female transplant candidates.

Methods: Organ Procurement and Transplantation Network data were retrospectively analyzed comparing 2013-2016 with 2018-2021 SLK listings. Waitlist outcomes and Model for End-stage Liver Disease (MELD) 3.0 reclassifications were compared by sex and listing period.

Results: There were 2626 and 2609 male patients and 1670 and 1919 female patients pre- and post-policy changes, respectively. The proportion of female SLK listings post-policy change (42.4%) was higher than both female SLK listings pre-policy change (38.9%) and female single-organ liver listings post-policy change (36.8%; P < 0.01). A statistically significant interaction between sex and listing group (pre- versus post-policy change) was present in multivariable analysis (P = 0.02). Female patients were more likely to have a higher MELD 3.0 score than the listing MELD/MELD-Na score when the listing MELD score was <30 (P < 0.01). Among all patients who died on the waitlist, female patients were nearly twice as likely to be underrepresented by listing MELD compared with MELD 3.0 (23% female and 13% male patients; P < 0.01).

Conclusions: Waitlist outcomes were changed differentially between male and female patients after the 2017 SLK policy change. The application of MELD 3.0 to SLK patients is likely to benefit female patients.