The grade of obesity affects the noninvasive diagnosis of advanced fibrosis in individuals with MASLD.

Objective: Metabolic dysfunction-associated steatotic liver disease (MASLD) is closely associated with obesity. We aimed to assess the impact of obesity on the performance of different noninvasive tests, including liver stiffness measurement (LSM) and Agile3+ (A3+), to detect advanced fibrosis (AF) in a population of patients with MASLD encompassing a wide range of BMI values.

Methods: A total of 479 patients with MASLD were consecutively included (Lyon Hepatology Institute). Clinical data and noninvasive tests, including FibroTest, LSM, A3+, Fibrosis-4 (FIB-4), magnetic resonance elastography, and liver biopsies, were collected. AF was determined by a composite endpoint, i.e., histological stage ≥ F3, overt diagnosis of cirrhosis by magnetic resonance elastography, or concordant LSM ≥ 9.6 kPa and FibroTest ≥ F3.

Results: The median BMI was 35.0 kg/m, and the prevalence of AF was 28.6%. Patients with BMI ≥ 35 versus <35 had a lower proportion of AF, i.e., 19.3% versus 38.1% (p < 0.001), but higher indeterminate status for AF (34.2% vs. 15.4%; p < 0.001). In the case of BMI ≥ 35, LSM had lower specificity to rule in AF (77.9%) versus A3+ (90.4%), but A3+ had decreased sensitivity to rule out AF. A sequential LSM/A3+ strategy achieved high specificity to rule in AF and lowered the proportion of indeterminate cases in patients with BMI ≥ 35.

Conclusions: The grade of obesity affects the detection of MASLD-related AF. A sequential use of LSM/A3 could improve AF detection in patients with BMI ≥ 35.