UC San Diego

Background and aims

Patients with NAFLD with significant hepatic fibrosis (Stage ≥ 2) are at increased risk of liver-related morbidity and are candidates for pharmacologic therapies. In this study, we compared the diagnostic accuracy of MEFIB (the combination of magnetic resonance elastography [MRE] and Fibrosis-4 [FIB-4]) and FAST (FibroScan-aspartate aminotransferase; combined liver stiffness measurement by vibration-controlled transient elastography, controlled attenuation parameter, and aspartate aminotransferase) for detecting significant fibrosis.

Approach and results

This prospective cohort study included 234 consecutive patients with NAFLD who underwent liver biopsy, MRE, and FibroScan at the University of California San Diego (UCSD cohort) and an independent cohort (N = 314) from Yokohama City University, Japan. The primary outcome was diagnostic accuracy for significant fibrosis (Stage ≥ 2). The proportions of significant fibrosis in the UCSD and Yokohama cohorts were 29.5% and 66.2%, respectively. Area under the receiver operating characteristic curve (95% CI) of MEFIB (0.860 [0.81-0.91]) was significantly higher than that of FAST (0.757 [0.69-0.82]) in the UCSD cohort (p = 0.005), with consistent results in the Yokohama cohort (AUROC, 0.899 [MEFIB] versus 0.724 [FAST]; p < 0.001). When used as the rule-in criteria (MEFIB, MRE ≥ 3.3 kPa and FIB-4 ≥ 1.6; FAST ≥ 0.67), the positive predictive value for significant fibrosis was 91.2%-96.0% for MEFIB and 74.2%-89.2% for FAST. When used as the rule-out criteria (MEFIB, MRE < 3.3 kPa and FIB-4 < 1.6; FAST ≤ 0.35), the negative predictive value for significant fibrosis was 85.6%-92.8% for MEFIB and 57.8%-88.3% for FAST.

Conclusions

MEFIB has higher diagnostic accuracy than FAST for significant fibrosis in NAFLD, and our results support the utility of a two-step strategy for detecting significant fibrosis in NAFLD.