Changing national practice patterns in living donor BMI and liver biopsy utilization from 2000-2024

Background: Living donor liver transplantation (LDLT) remains an important alternative to deceased donor transplantation amid organ shortages. However, rising obesity may limits its growth through increased steatosis and decreased donor approval. We evaluated trends in donor and recipient BMI, liver biopsy utilization, and the association between donor obesity and recipient outcomes from 2000-2024. Methods: Adult transplant recipients and donors from 2000-2024 were identified using the UNOS STAR file. Temporal BMI trends were assessed using annual percent change (APC). Liver biopsy utilization was evaluated overall and stratified by donor obesity status (BMI ≥30 kg/m 2 ), center volume, and UNOS region. Secondary outcomes included length of stay and post-operative complications. Post-transplant survival was assessed using Cox proportional hazard models, with multivariable regression adjusting for a priori selected covariates. Results: Among 7,942 donor-recipient pairs, recipient median BMI increased from 25.9 to 26.8 kg/m 2 , (APC 0.1%, p =0.01), while donor BMI increased from 24.6 to 27.6 kg/m 2 (APC 0.4%, p <0.001). Despite increasing BMI, liver biopsy utilization declined from approximately 45%-50% in the mid-2000s to 6% by 2024 (APC −8.3%). Biopsy utilization remained higher among obese donors and declined more slowly (APC −5.8%). Donor BMI was not associated with transplant length of stay, post-operative complications (reoperation, vascular/biliary complications, readmissions), or post-transplant recipient survival (OR 1.00, 95% CI 0.99-1.01, p =0.42). Conclusions: Donor and recipient BMI have both increased since 2000, yet donor obesity was not associated with inferior recipient outcomes. Liver biopsy utilization has declined substantially, with persistent regional and center-level variation. Standardization of steatosis assessment may help expand the living donor pool without compromising outcomes. Future studies should assess graft-specific outcomes and long-term steatosis recurrence.