S2624 Impact of Obesity on Pre- and Post- Orthotopic Liver Transplantation Outcomes: A Comparative Analysis Across Body Mass Index (BMI) Classes

Introduction: The number of obese patients undergoing orthotopic liver transplantation (OLT) is increasing in the United States. The impact of obesity on OLT remains debated. This study aims to evaluate the impact of obesity on pre- and post-OLT outcomes across different BMI categories in our tertiary care center. Methods: A single-center analysis of all adult patients who underwent OLT at Corewell Health William Beaumont University Hospital between 2013-2023 was conducted. Clinical, laboratory, histological, and follow-up data were retrieved from electronic medical records. Primary outcomes were intensive care unit (ICU) and hospital length of stay (LOS). Secondary outcomes were laboratory values at time of OLT, and post OLT infections. Categorical variables are reported as numbers and percentages, and the continuous variables are reported as median (med) with interquartile range (IQR) or means with standard deviation. Statistical significance was defined as P ≤ 0.05 for all the parameters. Results: A total of 239 OLT recipients were identified. Normal weight (BMI 18.5–24.9, 15%), Overweight (BMI 25.0–29.9, 30%), Obesity I (BMI 30.0–34.9, 26%), Obesity II (BMI 35.0–39.9, 9%), Obesity III (BMI ≥40.0, 5%), and Underweight (BMI <18.5, 0.01%). Obesity III patients required significantly longer ICU stays post-OLT (med = 12 days) compared to normal weight (med = 5 days, P = 0.001). Hospital LOS was prolonged in Obesity III (med = 25 days) compared to normal weight (med = 11 days, P = 0.01). Total bilirubin levels were elevated in Obesity III (med = 24 mg/dL) compared to both Obesity I (med = 6.2 mg/dL, P = 0.01) and normal weight (med = 4.8 mg/dL, P = 0.02). Obesity III patients exhibited lower hemoglobin (med = 8.4 g/dL) than normal weight (med = 10 g/dL, P = 0.01) and reduced platelet counts (med = 52 × 10³/mm³) compared to normal weight (med = 84 × 10³/mm³, P = 0.03). Post-OLT infections were more frequent in Obesity III patients (50%) than in normal weight individuals (13.9%, P = 0.05). Conclusion: Obesity III demonstrated significantly worse pre- and post-OLT outcomes compared to normal weight. Elevated bilirubin, lower hemoglobin, and reduced platelets in Obesity III suggest greater pre-OLT disease severity. Postoperatively, Obesity III experienced prolonged ICU, hospital LOS and higher infection rates. Further research, including prospective studies, is needed to better understand these outcomes.