Metabolic Dysfunction-Associated Steatotic Liver Disease in Severe Obesity and Concordance between Invasive (Biopsy) and Noninvasive (OWLiver®) Diagnoses

Introduction: Nonalcoholic fatty liver disease (NAFLD), now termed metabolic dysfunction-associated steatotic liver disease (MASLD), is an escalating health concern linked to obesity and type 2 diabetes. Despite liver biopsy being the gold standard, its invasiveness underscores the need for noninvasive diagnostic methods. Methods: A cross-sectional study was performed to assess MASLD using the noninvasive OWLiver ^® serum lipidomics test in a cohort of 117 patients with severe obesity undergoing bariatric surgery, comparing outcomes with liver biopsy. Exclusions (n = 24) included insufficient data, liver disease etiology other than MASLD, corticosteroid treatment, excessive alcohol consumption, low glomerular filtration rate, and declination to participate. Comprehensive laboratory tests, demographic assessments, and liver biopsies were performed. Serum metabolites were analyzed using OWLiverR, a serum lipidomic test that discriminates between healthy liver, steatosis, metabolic dysfunction-associated steatohepatitis (MASH), and MASH with fibrosis ≥2 by means of three algorithms run sequentially. Results: Liver biopsy revealed a MASLD prevalence of 95.7%, with MASH present in 28.2% of cases. OWLiverR demonstrated a tendency to diagnose more severe cases. Body mass index (BMI), rather than the presence of type 2 diabetes, emerged as the sole independent factor linked to the probability of concordance. Therefore, the all-population concordance of 63.2% between OWLiver ^® and liver biopsy notably raised to 77.1% in patients with a BMI <40 kg/m ². These findings suggest a potential correlation between lower BMI and enhanced concordance between OWLiver ^® and biopsy. Conclusion: This study yields valuable insights into the concordance between liver biopsy and the noninvasive serum lipidomic test, OWLiver ^®, in severe obesity. OWLiver ^® demonstrated a tendency to amplify MASLD severity, with BMI values influencing concordance. Patients with BMI <40 kg/m2 may derive optimal benefits from this noninvasive diagnostic approach.