Validation of a two-step approach combining serum biomarkers and liver stiffness measurement to predict advanced fibrosis.

Background and aim The Gut and Obesity in Asia Workgroup recently reported that a two-step approach using fibrosis scores followed by liver stiffness measurement (LSM) could accurately detect patients with non-alcoholic fatty liver disease (NAFLD) having advanced fibrosis in low-risk fibrosis populations. This study aimed to validate the utility of this approach using a Japanese health checkup registry. Methods This cross-sectional study included subjects who underwent a health checkup from 2014 to 2019. Using estimated fibrosis stage measured by LSM as a standard, we calculated the percentage of misclassification from assessments made based on fibrosis scores (NAFLD fibrosis score [NFS] or Fibrosis-4 score [FIB-4]) and LSM, alone or in combination. Results Of 630 subjects with NAFLD, 4 (0.8%) had advanced fibrosis. In the first-step evaluation, only 21.4-38.0% of subjects needed further testing. This approach was associated with a high specificity of approximately 100% and a negative predictive value of 99.7%. The percentage of misclassification based on NFS or FIB-4 values followed by LSM in all subjects and using LSM after NFS or FIB-4 determination only in subjects with indeterminate/high NFS or FIB-4 values (two-step approach) was 0% and 0.3% and 0.16% and 0.3%, respectively. In addition, very few false negatives occurred for both NFS and FIB-4. Conclusion The two-step approach helps to identify the subjects with NAFLD who have advanced fibrosis during a routine health checkup and is associated with only a few false negatives.