Background: In 2016, nearly 40% of the US population was classified as obese, and current projections indicate that obesity will affect 50% of the population by 2030. Inevitably, patients evaluated for surgical intervention with hepatic malignancy will present with increasing Body Mass Indices (BMI). However, the impact of BMI in liver surgery for malignancy is less well defined. Previous studies examining BMI and hepatectomy place all obese patients in a single cohort. The goal of this study is to stratify patients who underwent hepatic resection for malignancy by BMI group to determine the short term outcomes between BMI and perioperative outcomes. Methods: A retrospective review was performed of the NSQIP hepatectomy database from 2014–2016. Patients included were >18 years of age and underwent liver resection for malignancy. Patients were subdivided into BMI classes based on the WHO classification for obesity. For BMI categories: < 18.5 = Underweight, 18.5-24.9 = Normal, 25-29.9 = Overweight, 30-34.9 = Obese I, 35-39.9 = Obese II, 40+ = Obese III. Univariate analyses were performed using t-test, Mann-U and Anova. Unadjusted survival was performed via Kaplan Meier log-rank method followed by multivariate Cox proportional hazards modeling to adjust for confounders. Significance was determined to an alpha error of < 0.05. Results: There were 8400 patients identified who underwent resection for liver malignancy. Class II and III obesity patients were more likely to be female, on insulin, more often ASA class 3 OR 4, and were more likely to undergo partial hepatectomy (p<0.01, ALL). Obese class II and III patients were less likely to have viral hepatitis and primary liver cancer (p< 0.01 and p = 0.05). All obese groups were less likely to have cirrhotic liver texture and more likely to have steatosis (p = 0.01). No difference was observed between open vs. laparoscopic approach among BMI categories (p = 0.32). The percentage of any complications was highest in the Underweight group (39%), followed by the Normal (33%) and lower in all obese groups (29-30%, p = 0.03). Major complications occurred most frequently in the Normal and Overweight groups (p = 0.03). In fact, Class I obese groups had lower odds of complications on multivariate analysis (OR 0.75, 95%CI (0.62-0.9), p = 0.02). Unadjusted short-term mortality was not different between the BMI groups (p = 0.06)(graph). However, predictors of 30 day mortality included signs of liver dysfunction such as elevated INR (HR 1.14, 95%CI (1.06–1.22) p < 0.001), low platelets (HR 0.76, 95%CI (0.63–0.91), p = 0.003 and albumin (HR 0.70, 95%CI (0.59–0.83), p < .001, and class II obesity (HR 2.03, 95%CI (1.04-3.98), p = .039). Conclusion: Higher BMI does not significantly impact the rate of perioperative complications after hepatectomy for malignancy. Inherent selection bias toward more partial resections and less native liver disease in obese patients, particularly the Obese I and Obese II categories, may account for these results. Careful selection of appropriate surgical candidates among the obese appears warranted; however, with the caveat that a higher perioperative mortality occurs among the Obese II category who undergo hepatectomy.
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May 6, 2024
Meriam Dalhoum + 9
Open Access