Selecting the Target Population for Screening of Hepatic Fibrosis in Primary Care Centers in Korea

Diagnostic performance of the fibrosis-4 index and the NAFLD fibrosis score for screening at-risk individuals in a health check-up setting

BACKGROUND

The fibrosis-4 index (FIB-4) and the NAFLD fibrosis score (NFS) have been used as noninvasive screening methods for advanced fibrosis in patients with NAFLD. However, their diagnostic performance has not been evaluated in at-risk individuals regardless of hepatic steatosis. This study evaluated the performance of the FIB-4 and NFS in at-risk groups of health check-up examinees at mass screening centers.

METHODS

This retrospective, cross-sectional study included 8545 participants who underwent voluntary magnetic resonance elastography at a discounted fee during their regular health check-ups at 13 mass screening centers nationwide. The at-risk group was defined as those with any of the following conditions: NAFLD, 2 or more metabolic abnormalities, diabetes mellitus, or abnormal aminotransferase levels. A magnetic resonance elastography cutoff of ≥3.6 kPa was used to define conventional advanced fibrosis.

RESULTS

According to the proposed criteria, the proportion of at-risk individuals was 67.4%-80.2% in the health check-up cohort without viral or alcohol-associated liver disease. The prevalence of individuals with advanced hepatic fibrosis in each at-risk group was ~2.3%-2.8% according to various criteria. It was higher in patients without NAFLD than in those with NAFLD. A total of 28.2%-39.6% of those in each at-risk group did not show hepatic steatosis on ultrasonography. The performance of FIB-4 for advanced fibrosis in the at-risk group was comparable with that in the NAFLD group. FIB-4 showed a better area under the receiver operating characteristic curve and sensitivity than NFS in the at-risk group.

CONCLUSIONS

FIB-4 demonstrated superior performance compared with the NFS, and its performance in at-risk individuals was similar to that observed for patients with NAFLD.

Reappraisal of fibrosis-4 index and non-alcoholic fatty liver disease fibrosis score for advanced fibrosis in average-risk population

BACKGROUND AND AIM

The current cut-offs for fibrosis-4 (FIB-4) and non-alcoholic fatty liver disease fibrosis score (NFS) are suboptimal for screening because of low accuracy and high false-negative rates in average-risk populations. This study aimed to reappraisal the performance of FIB-4 and NFS in such average-risk populations.

METHODS

This is a cross-sectional study, which retrospectively reviewed the magnetic resonance elastography (MRE) data of 8,522 subjects. Individuals with history of significant alcohol consumption and those with positive viral serologic markers were excluded. Finally, 6,215 average-risk individuals were analyzed.

RESULTS

The area under the receiver operating characteristic curves (AUROCs) of FIB-4 for the diagnosis of advanced hepatic fibrosis was higher than that in the NFS especially in the metabolically healthy. The AUROCs of FIB-4 for in the average-risk population was also higher than that in the NFS (0.840 in FIB-4 vs. 0.798, P = 0.036). However, the sensitivity of FIB-4 and NFS was low (69.6 and 61.4%, respectively) in applying the current cut-off of FIB-4 [1.3 (2.0)] and NFS [-1.455 (0.12)]. At cut-off of FIB-4 at 1.0, sensitivity (90.2%), and negative predictive value (99.7%) were improved.

CONCLUSION

The diagnostic performance of FIB-4 was better than that of NFS for screening hepatic fibrosis in average-risk populations. It is recommended to use FIB-4 rather than NFS, when screening for hepatic fibrosis in general population.

Noninvasive Liver Fibrosis Staging: Comparison of MR Elastography with Extracellular Volume Fraction Analysis Using Contrast-Enhanced CT

Purpose: To compare the accuracy of liver fibrosis staging with MR elastography and of staging with extracellular volume fraction (fECV) analysis using contrast-enhanced CT. Methods: This retrospective study included 60 patients who underwent both MR elastography and contrast-enhanced CT before liver surgery between October 2013 and July 2020. Two radiologists independently measured liver stiffness of MR elastography and fECV of CT images. Accuracy for liver fibrosis staging was assessed using receiver operating characteristic (ROC) analysis. Correlations between liver stiffness or fECV and liver fibrosis were also evaluated by means of the Spearman rank correlation coefficient. Results: The areas under the ROC curves for MR elastography for each stage differentiation of ≥F1 (0.85, 0.82 for the two radiologists), ≥F2 (0.88, 0.89), ≥F3 (0.87, 0.86), and F4 (0.84, 0.83) were greater than those for fECV analysis with CT (0.64, p = 0.06, 0.69, p = 0.2; 0.62, p < 0.005, 0.63, p < 0.005; 0.62, p < 0.005, 0.62, p < 0.01; and 0.70, p = 0.08, 0.71, p = 0.2, respectively). The correlation coefficients between liver stiffness and liver fibrosis in A0 (0.67, 0.69 for the two radiologists), A1 (0.64, 0.66) and A2 group (0.58, 0.51) were significantly higher than those between fECV and liver fibrosis (0.28, 0.30; 0.27, 0.31; and 0.23, 0.07; p < 0.05 for all comparisons). Conclusion: MR elastography allows for more accurate liver fibrosis staging compared with fECV analysis with CT. In addition, MR elastography may be less affected than fECV analysis by the inflammatory condition.