APRI and FIB-4 for Liver Fibrosis Assessment in Chronic Hepatitis B: Evidence from a Hyperendemic Andean Setting

Background/Objectives: The 2024 WHO guidelines incorporated the APRI index into treatment decisions for chronic hepatitis B, with thresholds of >0.5 for significant fibrosis and >1.0 for cirrhosis, because it can be computed when neither biopsy nor elastography is available. The evidence supporting those thresholds derives almost entirely from studies using liver biopsy as reference standard; how serological indices behave when the available comparator is elastography remains unknown, and no data exist for Andean populations. We aimed to quantify the agreement of APRI and FIB-4 with transient elastography, determine whether either discriminates better, and evaluate the 2024 WHO thresholds in this setting.

Methods

Retrospective agreement study of patients in the Hepatitis B Elimination Plan of Huanta, Peru. APRI and FIB-4, computed from routine laboratory results, were compared against transient elastography (FibroScan 402, M+ probe) used as a reference standard given the unavailability of biopsy. Outcomes followed the 2024 WHO thresholds: >7.0 kPa for significant fibrosis and >12.5 kPa for cirrhosis. Only examinations meeting the pre-specified quality criterion (at least 10 valid measurements; IQR/median ≤ 30%) were analyzed. Diagnostic properties were estimated with exact confidence intervals and likelihood ratios, areas under the curve with bootstrap intervals, and the between-index comparison with DeLong’s test for paired curves. Reporting followed STARD 2015.