In partial fulfilment of the requirements for the degree of Master in Medical Research.

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is increasingly common worldwide, especially in South Asia. Liver fibrosis is the most critical factor influencing long- term outcomes in MASLD. FibroScan is a trusted non-invasive method to assess fibrosis. Its high cost and limited availability in settings like Nepal make simpler alternatives necessary. The Fibrosis-4 (FIB-4) index, based on routine lab tests, is one such option-but its accuracy in the Nepalese MASLD population remains unclear. This study aimed to assess the diagnostic accuracy of the FIB-4 index in detecting hepatic fibrosis in MASLD compared to FibroScan at a tertiary care center in Nepal.
Materials and methods: A cross-sectional diagnostic accuracy study was carried out at Nobel Medical College in Biratnagar, involving 135 adult patients diagnosed with MASLD. FIB-4 scores were calculated and compared against liver stiffness measurements (LSM) obtained via FibroScan. We evaluated the sensitivity, specificity, and overall diagnostic accuracy of FIB-4 at different cutoff values.
Results: FIB-4 showed good diagnostic performance: AUROC 0.852 for significant fibrosis (≥7 kPa) and 0.868 for advanced fibrosis (29.7 kPa). At a cut-off above 1.3, it identified significant fibrosis (LSM 27 kPa) with 86.6% sensitivity and 66.0% specificity. A higher cut-off (>2.67) yielded excellent specificity (92.5%) for confirming fibrosis, though with lower sensitivity. For advanced fibrosis (LSM 29.7 kPa), FIB-4 achieved 80.0% sensitivity and 95.0% specificity. FIB-4 scores also rose progressively with the fibrosis stage and had a strong correlation with FibroScan values (r = 0.776).
Conclusion: FIB-4 is a reliable, affordable tool for assessing liver fibrosis in MASLD and may serve as a practical alternative where FibroScan is not accessible.