Validation and Refinement of Noninvasive Methods to Assess Hepatic Fibrosis: Magnetic Resonance Elastography Versus Enhanced Liver Fibrosis Index

Background: Noninvasive fibrosis markers are routinely used in patients with liver disease. Magnetic resonance elastography (MRE) is recognized as a highly accurate methodology, but a reliable blood test for fibrosis would be useful. We examined performance characteristics of the Enhanced Liver Fibrosis (ELF) Index compared to MRE in a cohort including those with HCV, HIV, and HCV/HIV. Methods: Subjects enrolled in the Miami Adult Studies on HIV (MASH) cohort underwent MRE and blood sampling. The ELF Index was scored and receiver–operator curves constructed to determine optimal cutoff levels relative to performance characteristics. Cytokine testing was performed to identify new markers to enhance noninvasive marker development. Results: The ELF Index was determined in 459 subjects; more than half were male, non-white, and HIV-infected. MRE was obtained on a subset of 283 subjects and the group that had both studies served as the basis of the receiver–operator curve analysis. At an ELF Index of > 10.633, the area under the curve for cirrhosis (Metavir F4, MRE > 4.62 kPa) was 0.986 (95% CI 0.994–0.996; p < 0.001) with a specificity of 100%. For advanced fibrosis (Metavir F3/4), an ELF cutoff of 10 was associated with poor sensitivity but high specificity (98.9%, 95% CI 96.7–99.8%) with an AUC of 0.80 (95% CI 0.749–0.845). ELF Index performance characteristics exceeded FIB-4 performance. HCV and age were associated with increased fibrosis (p < 0.05) in a multivariable model. IP-10 was found to be a promising biomarker for improvement in noninvasive prediction algorithms. Conclusions: The ELF Index was a highly sensitive and specific marker of cirrhosis, even among HIV-infected individuals, when compared with MRE. IP-10 may be a biomarker that can enhance performance characteristics further, but additional validation is required.