Routine Versus Selective Liver Biopsy During Bariatric Surgery: Postoperative Outcomes and Preoperative Predictors of NASH.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) is common in patients with obesity. Liver biopsy (LB) can be routinely or selectively performed during bariatric surgery to identify patients with NASH. METHODS: Patients undergoing bariatric surgery between 2016 and 2020 at our institution were identified. Chart review identified patients undergoing concurrent LB. LB results were compared between patients undergoing routine LB and selective LB. Patient demographics and postoperative outcomes were compared between those who received LB and those who did not (non-LB). In the LB cohort, preoperative characteristics of patients with NASH were compared to those without NASH, and multivariable regression was used to identify predictors of NASH. RESULTS: Two thousand three hundred ninety-three patients were identified, of which 400 (16.7%) had liver biopsies (LB) and 1,993 (83.3%) did not (non-LB). Three hundred thirty LB were performed routinely, and 70 were selective. Compared to selective LB, routine LB identified significantly higher rates of steatosis (83.6% vs. 4.5%, p < 0.01), periportal inflammation (67.0% vs. 3.2%, p < 0.01), fibrosis (65.8% vs. 2.1%, p < 0.01), and NASH (10.9% vs. 1.5%, p < 0.01). There were no differences in postoperative complications, blood transfusions, readmissions, or reoperations between LB and non-LB. On multivariable regression, highest BMI > 40 (OR 2.85, 95% CI 1.43-5.67) and insulin-dependent diabetes (OR 4.83, 95% CI 1.70-13.69) were associated with a higher odds of NASH, while Black race was associated with lower odds (OR 0.25, 95% CI 0.09-0.65). CONCLUSIONS: Routine liver biopsies during bariatric surgery identify higher rates of advanced NAFLD compared to selective biopsies, and can be safely performed without an increased risk of postoperative complications.