Diagnostic accuracy of FibroScan-AST score to identify nonalcoholic steatohepatitis with significant activity and fibrosis in Japanese patients with nonalcoholic fatty liver disease: comparison between M and XL probes.

AIM: Recently, FibroScan-AST (FAST) score was reported to be effective for identifying nonalcoholic steatohepatitis (NASH) with significant activity and fibrosis in nonalcoholic fatty liver disease (NAFLD). The aim of this study was to confirm the diagnostic accuracy of FAST score of Japanese patients and compare the cut-off values and diagnostic accuracy between the FibroScan(R) M and XL probes. METHODS: Eighty-two and 84 patients were included the verification and validation sets, respectively. All patients were diagnosed with NAFLD via biopsy by two central expert pathologists. Liver stiffness measurements and controlled attenuation parameter were performed, and diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: No significant difference existed in FAST score between the M and XL probes (0.489 vs 0.483, p=0.187). No significant difference existed in the area under the ROC between the two probes (M, 0.7598; XL, 0.7614; p=0.958). According to the Youden index, the cut-off value using the M probe was 0.57 with 68.2% sensitivity and 78.3% specificity. For the XL probe, the cut-off value was 0.56 with 68.2% sensitivity and 73.3% specificity. To obtain sensitivity and specificity values higher than 90%, cut-off values of 0.35 and 0.66 were chosen for the M probe and 0.32 and 0.63 were chosen for the XL probe. CONCLUSIONS: There was no significant difference in diagnostic accuracy of FAST score between the FibroScan(R) M and XL probes. FAST score can be used to identify NASH with significant risk in Japanese patients regardless of probe selection.