Liver and Bile
Hepatology. 2023;77(3):920–30
Validation of the new 2021 EASL algorithm for the non-invasive diagnosis of advanced fibrosis in NAFLD
Background and aims: The European Association for the Study of the Liver (EASL) has recently proposed an algorithm for the diagnosis of advanced liver fibrosis. The authors aimed to evaluate the diagnostic accuracy of this algorithm in non-alcoholic fatty liver disease (NAFLD).
Approach and results: 1051 patients with NAFLD, liver biopsy, and 4 non-invasive tests (NITs; Fibrosis-4 [FIB-4], vibration-controlled transient elastography [VCTE], FibroMeter, Fibrotest) were included. The enhanced liver fibrosis (ELF) score was available in 396 patients. A cohort of 230 patients from primary care/diabetes clinics had FIB-4, VCTE, and ELF. Compared with the performance of single NITs, agreement between 2 NITs (FIB-4 and VCTE, VCTE and patented serum tests) increased specificity and positive predictive value (PPV) by 20%, thus justifying the sequential use proposed in the EASL algorithm. The FIB-4/VCTE/FibroMeter and FIB-4/VCTE/Fibrotest algorithms performed similarly, providing 85% diagnostic accuracy and a liver biopsy requirement rate of only 10%. The FIB-4/VCTE/ELF algorithm performed similarly in the subgroup where ELF was available. Simulations of algorithm accuracies at different prevalence showed that PPVs rapidly increased, reaching a plateau above 75% starting at 15% prevalence. Negative predictive values (NPVs) remained higher than 90% up to 25% prevalence. The rate of liver biopsy requirement remained stable, increasing by only 5% between low- and high-prevalence settings. When the EASL algorithm was applied in the primary care/diabetes clinic cohort, liver biopsy requirement was only 3%, and the agreement among the 3 steps provided 75% PPV.
Conclusions: The present study validates the algorithm proposed by the EASL in its latest 2021 guidelines for the diagnosis of advanced fibrosis in the setting of non-alcoholic fatty liver disease.