Magnetic resonance elastography combined with fibrosis-4 index for diagnosing at-risk metabolic dysfunction-associated steatohepatitis: a systematic review and meta-analysis of diagnostic test accuracy studies

BACKGROUND: Patients with metabolic dysfunction-associated steatohepatitis (MASH; nonalcoholic fatty liver disease activity score ≥4) and significant fibrosis (≥F2; at-risk MASH) are at increased risk for disease progression. Magnetic resonance elastography (MRE) combined with the fibrosis-4 (MEFIB) index enables the noninvasive diagnosis of at-risk MASH and significant fibrosis. We assessed the performance of the MEFIB index for ruling in/out both target conditions. METHODS: We analyzed studies up to February 2025 assessing the performance of MEFIB index for ruling in (MRE≥3.3 kPa plus FIB-4≥1.6) and out (MRE<3.3 kPa plus FIB-4<1.6) at-risk MASH or significant fibrosis, using liver biopsy as the reference standard. We calculated pooled diagnostic accuracy estimates using bivariate random-effects models. RESULTS: We included 7 studies with 3356 participants. For ruling in at-risk MASH, the MEFIB index yielded a pooled specificity of 0.94 (95% confidence interval [CI] 0.74-0.99), and a positive likelihood ratio (LRp) of 5.3 (95%CI 1.8-15.7). For ruling out at-risk MASH, the MEFIB index had a pooled sensitivity of 0.77 (95%CI 0.62-0.88) and a negative likelihood ratio (LRn) of 0.34 (95%CI 0.23-0.52). For ruling in significant fibrosis, the MEFIB index achieved a summary specificity of 0.93 (95%CI 0.85-0.97) with LRp 8.2 (95%CI 4.5-14.9). For excluding significant fibrosis, the pooled sensitivity and LRn of the MEFIB index were 0.88 (95%CI 0.79-0.94) and 0.16 (95%CI 0.08-0.31), respectively. CONCLUSIONS: MEFIB index has acceptable accuracy for diagnosing at-risk MASH and significant fibrosis. Proposed thresholds can be used to identify both target conditions in high prevalence settings and facilitate patient recruitment in clinical trials.