Donor obesity and MASLD as barriers to living donor liver transplantation: Institutional attrition and national outcomes

Background & Aims: Obesity and metabolic dysfunction-associated steatotic liver disease (MASLD) are major barriers to access to living donor liver transplantation (LDLT) and increasingly prevalent among potential LDLT-donors. The extent to which obesity drives donor attrition during referral/evaluation and whether carefully selected donors with obesity associate with inferior outcomes are poorly defined. We aimed to characterize donor attrition from obesity and MASLD and evaluate donor/recipient outcomes among donors with obesity. Methods: All adult LDLT-donor referrals (n=1,963) at a high-volume US center (2018-2024) were included. Donor progression through screening, evaluation, and donation was assessed by BMI category. Institutional data were complemented by national SRTR-Registry analysis of association between donor BMI and recipient survival in adult LDLT recipients (2010- 2024). Results: From 1,963 referrals, 843 completed preliminary screening, including 295 donors with obesity. Only 14% of donors with obesity proceeded to donation versus 22% without obesity. Most donors with obesity were excluded before in-person evaluation, and >50% were declined after evaluation, most commonly due to MASLD. Donors with obesity proceeding to donation experienced longer evaluation-to-donation intervals but similar surgical complication profiles. Recipient outcomes did not differ by donor obesity status, including biliary or vascular complications or one-year recipient survival. In national analyses, donor BMI was not independently associated with recipient survival. Conclusions: Obesity and MASLD are dominant drivers of early donor attrition in LDLT, frequently limiting access before definitive evaluation. However, carefully selected donors with Class I obesity demonstrate preserved donor safety and comparable recipient outcomes at both institutional and national levels. These findings support a more individualized donor assessment strategy that prioritizes metabolic evaluation rather than BMI alone while maintaining donor safety and access to living donation.