Metabolic Dysfunction-associated Steatotic Liver Disease in Adolescent and Young Adult Patients Undergoing Bariatric Surgery: When to Biopsy?

Introduction: Metabolic dysfunction-associated steatotic liver disease (MASLD) is prevalent in adolescent and young adults (AYA) with obesity. However, the role of liver biopsy during metabolic bariatric surgery (MBS) is debated. Methods: This is a retrospective chart review of AYA patients < 22 years old who underwent MBS between 2014-2023 at two institutions. A policy of selective liver biopsy was used for the majority of the study, but both sites had periods of routine biopsy. Selective biopsy was based on preoperative factors associated with MASLD. Patients with steatosis, fibrosis, or steatohepatitis on histology were considered to have a diagnosis of MASLD. Preoperative laboratory markers were evaluated for association with MASLD using multivariate regression. Results: Among 240 patients, 121 (50%) underwent biopsy, with 63 (53%) performed during routine biopsy periods. The remaining 56 biopsies (32%) were in the 177 patients who underwent MBS during a selective period. There was no difference in rate of positive biopsy between routine (47, 75%) and selective (44, 79%) groups (p=0.61). Steatohepatitis was present in 28 (23.5%) of patients and ≥ Stage 2 fibrosis in 13 (10.9%) of patients. Elevated BMI, ALT, and HbA1c were associated with a diagnosis of MASLD. Among 28 routine-biopsy patients with normal preoperative laboratory markers, 16 (57.1%) had MASLD on biopsy. Conclusion: In our cohort, selective biopsy was no more effective than chance at identifying patients with MASLD, suggesting a high rate of missed diagnoses. This presents an opportunity to standardize biopsy protocols including consideration of routine liver biopsy in AYA patients undergoing MBS.