Utility of the fibrosis-3 index for predicting liver fibrosis 5 years after achieving sustained virological response in patients with chronic hepatitis C

Aim: Non-invasive tests for liver fibrosis frequently use serum aminotransferases; however, their accuracy may be influenced by hepatitis virus eradication. This study evaluated the effectiveness of the age-independent FIB-3 index in patients with chronic hepatitis C who achieved sustained virological response (SVR). Methods: A total of 115 patients who achieved SVR following interferon therapy were analyzed. Liver fibrosis was assessed by biopsy before treatment and 5 years after achieving SVR. The diagnostic accuracies of the FIB-3 and FIB-4 indices were compared using Receiver Operating Characteristic (ROC) curve analysis and representative cutoff values (FIB-3:3.5, FIB-4:2.67), with a specific focus on age-stratified performance. Results: Age-stratified analysis revealed distinct patterns in fibrosis index performance before and after SVR. Among patients aged ≥ 65 years, both indices demonstrated poor accuracy pre-SVR (FIB-3:0.35, FIB-4:0.29) but markedly improved post-SVR, with FIB-3 demonstrating significantly superior performance (accuracy: 0.82 vs 0.64). This improvement was primarily due to better specificity (FIB-3:0.85 vs FIB-4,0.60) while maintaining high sensitivity (0.62 vs 0.87). In patients aged < 65 years, both indices exhibited modest improvement post-SVR, with no significant differences observed. Conclusions: At established cutoff values, the FIB-3 index demonstrated significantly higher diagnostic performance than the FIB-4 index, particularly in patients aged ≥ 65 years who achieved SVR. These findings suggest that the FIB-3 index is a reliable tool for long-term monitoring of liver fibrosis after hepatitis C eradication.