BACKGROUND: This is the largest UK-based study on the effect of recipient body mass index (BMI) and its extremes (BMI <18.5 and BMI ≥35 kg/m²) on liver transplant (LT) outcomes. Its purpose was to analyze the BMI effect on post-LT mortality, graft loss, primary non-function (PNF), and graft vascular and biliary complications.

MATERIAL AND METHODS: Data were retrieved from a single-center LT database of 2,115 consecutive patients receiving first LT during period February 2004 to September 2015. Survivals were compared across the BMI groups; the effects of recipient BMI on survival, PNF, and graft vascular and biliary complications were analyzed via regression.

RESULTS: Autoimmune disease and nonalcoholic steatohepatitis were prevalent among underweight and morbidly obese adults, respectively. Graft survival was similar across BMI classes at 30 days and in 1, 2, 5, and 10 years (p=0.75) and on obese versus non-obese (p=0.33). BMI <35 kg/m² versus BMI ≥35 kg/m² mean graft survival was similar (p=0.84). BMI <18.5 kg/m² recipients tended to have inferior mean graft and patient survivals; however, the difference was non-significant (p=0.09 and p=0.1 respectively). BMI <18.5 kg/m² recipients were at higher risk of hepatic artery thrombosis (HR, 1.73, 95% CI 1.73–3, p<0.05). Adult underweight status was an independent HAT risk factor (HR 3, 95% CI 1–8.6, p=0.046). BMI class did not affect ischemic cholangiopathy risk (p=0.84). However, the overall biliary complication risk increased by 3% for every 1 kg/m² BMI rise.

CONCLUSIONS: Post-LT survival is independent of recipient BMI. Underweight status is linked to higher HAT risk. Biliary complication risk increases with rising recipient BMI. After appropriate recipient selection, recipient BMI extremes are not a contraindication for LT.

Keywords: Body Mass Index, Liver Transplantation, Obesity, Morbid