The diagnostic performance of non-invasive fibrosis markers for predicting fibrosis in primary biliary cholangitis patients

Aim: This study aimed to investigate the relationship between liver fibrosis measured by transient elastography and non-invasive fibrosis scoring systems, including Fibrosis-4 (FIB-4) and aspartate-aminotransferase (AST)-to-platelet ratio index (APRI), in patients with primary biliary cholangitis (PBC). Material and Methods: A total of 45 PBC patients followed in the Gastroenterology Clinic were included in this retrospective study. Transient elastography was performed on all participants, and liver stiffness measurement (LSM) values were recorded in kilopascals (kPa). Fibrosis was defined as LSM ≥ 6.3 kPa, while advanced fibrosis was defined as LSM ≥ 10.5 kPa. To calculate the APRI score, the formula [(AST / upper normal limit × 100) / platelet count] was used, and for the FIB-4 score, the formula [(age × AST) / (platelet count × √alanine aminotransferase)] was applied. Results: Liver fibrosis was identified in 71.1% (n = 32) of patients, with advanced fibrosis present in 40.0% (n = 18). Patients with fibrosis had higher APRI and FIB-4 scores compared to those without fibrosis. Also, the median APRI score (0.7 vs. 0.5, p < 0.001) and median FIB-4 score (2.4 vs. 1.6, p < 0.001) were higher in patients with advanced liver fibrosis than in those without. For detecting fibrosis, the AUROC values were 0.73 (95% CI: 0.58–0.89) for APRI and 0.84 (95% CI: 0.73–0.96) for FIB-4. FIB-4 also showed higher accuracy than APRI for identifying advanced fibrosis (AUROC: 0.78 vs. 0.70, p = 0.042). Conclusion: Both APRI and FIB-4 are useful non-invasive tools for detecting and staging fibrosis in PBC. However, FIB-4 demonstrated superior diagnostic performance compared to APRI, particularly in predicting advanced fibrosis. Incorporating these markers into routine clinical practice may reduce the need for invasive liver biopsy and help optimize patient management.