Validation of the FibroScan-AST (FAST) and Agile 3+ score in metabolic dysfunction-associated steatotic liver disease in a Russian cohort of patients

Introduction. The high prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) requires timely diagnosis of its progressive forms. Recently developed for this purpose FibroScan-AST (FAST) and Agile 3+ indices have shown good diagnostic capabilities, but have not been validated in a Russian cohort. Aim. To evaluate the diagnostic efficiency of the FAST and Agile 3+ scores in Russian patients with MASLD. Materials and methods. The medical records of 43 patients with histologically verified MASLD and transient elastography (TE) performed were analyzed. Non-invasive indices of progressive MASLD were calculated: FIB-4, FAST and Agile 3+. Results. All the studied methods demonstrated good diagnostic ability. FAST demonstrated the best results for detecting non-alcoholic steatohepatitis (NASH) + NAS ≥ 4 + F ≥ 2 compared to TE and FIB-4. The area under the ROC curve (AUROC) for FAST was 0.827 ± 0.064 (95% CI: 0.701–0.952, p < 0.0001); for FIB-4 and TE – 0.786 ± 0.069 (95% CI: 0.651–0.920, p = 0.001) and 0.758 ± 0.075 (95% CI: 0.610–0.905, p = 0.004), respectively. However, the standard FAST cutoff values (≤0.35 and ≥0.67) had low sensitivity in the study cohort: the number of indeterminate results was 60.5%. Optimization of the FAST cutoff values (≤0.41 and ≥0.52) reduced the proportion of indeterminate cases to 23.25% and increased the number of correctly classified patients (from 37.2% to 62.8%, p = 0.0012). For the diagnosis of progressive fibrosis (F ≥ 3), the Agile 3+ score showed the best result (AUROC = 0.825 ± 0.077 (95% CI: 0.675–0.976, p = 0.003)) compared to FIB-4 and TE, but recalculation of the threshold values did not lead to a significant improvement in the diagnostic ability of the Agile 3+. Conclusions. The FAST and Agile 3+ scores are effective for diagnosing progressive MASLD, but the FAST threshold values require adaptation for the Russian population.