The Impact of Donor-Recipient Weight Ratios and Body Surface Area Ratios on Outcomes After Adult Deceased Donor Whole-Liver Transplantation

Background. The impact of donor-recipient size mismatch on deceased donor whole-liver transplant (DDLT) outcomes remains underexplored. Weight ratio (WR) is a simple, readily available size-matching metric, whereas body surface area ratio (BSAR) requires additional calculations. We analyzed the impact of donor-recipient WR and BSAR on outcomes among adult DDLT recipients and compared their predictive abilities. Methods. We evaluated adult primary DDLTs in the United Network for Organ Sharing database from January 1, 2013, to January 1, 2024 (n = 69 511). Patients were divided into 5 WR and BSAR percentiles (<10th, 10th–20th, 20th–80th [reference], 80th–90th, and >90th). Cox models assessed associations with graft survival, patient survival, and length of stay (LOS). Kaplan-Meier and receiver operating characteristic (ROC) curves compared outcomes and predictive ability, respectively. Results. WR and BSAR both impacted outcomes. Lower percentiles were associated with modestly decreased graft and patient survival. Graft survival was decreased in the <10th WR percentile (WR ≤0.65; hazard ratio [HR], 1.13; 95% confidence interval [CI], 1.06-1.20; P < 0.001), 10th–20th WR percentile (0.65< WR ≤0.74; HR, 1.06; 95% CI, 1.01-1.13; P = 0.03), <10th BSAR percentile (BSAR ≤0.78; HR, 1.14; 95% CI, 1.08-1.21; P < 0.001), and 10th–20th BSAR percentile (0.78< BSAR ≤0.85; HR, 1.10; 95% CI, 1.04-1.16; P = 0.001). Only the <10th WR percentile was associated with worse patient survival (HR, 1.08; 95% CI, 1.01-1.15; P = 0.02), whereas both the <10th BSAR percentile and 10th–20th BSAR percentile were associated (HR, 1.09; 95% CI, 1.02-1.16; P = 0.007; HR, 1.07; 95% CI, 1.01-1.14; P = 0.02, respectively). Both <10th and >90th WR and BSAR percentiles prolonged LOS. ROC analysis revealed identical areas under the ROC curve for WR and BSAR, suggesting similar predictive ability (c-statistic = 0.62). Conclusions. WR and BSAR are both reasonable tools to assess donor-recipient size matching in DDLT. Lower size-matching ratios increased graft failure and mortality, whereas both extremes prolonged LOS. Given its simplicity and immediate availability during donor evaluation, WR may serve as a practical adjunct for donor-recipient size matching. Caution is warranted with WR ≤0.74 or BSAR ≤0.85.