Abstract: Objective The aim of this study was conducted to explore the clinical prediction of significant liver fibrosis by transient ultrasound elastography and the aspartate aminotransferase/platelet ratio index (APRI) combination in patients with autoimmune hepatitis (AIH). Methods 67 patients with AIH and 54 healthy individuals at physical examination were enrolled in our hospital between August 2019 and August 2022, and all received FibroScan detection for liver stiffness measurement (LSM) and blood routine for the calculation of APRI. The patients with AIH underwent liver biopsies. The receiver operating characteristic curve (ROC) was applied to analyze the diagnostic performance of APRI and LSM for predicting significant liver fibrosis (SLF, >=S2) in patients with AIH. Results Serum AST level in patients with AIH was (104.3±21.9)U/L, significantly higher than [(30.5±5.1)U/L, P<0.05], the APRI and LSM were (1.4±0.1) and (8.1±1.2)kPa, both significantly greater than [(0.4±0.1) and (4.3±0.7)kPa, P<0.05], while the peripheral blood platelet count was (157.8±23.1)×10⁹/L, significantly less than [(208.5±20.7)×10⁹/L, P<0.05] in the healthy control; the liver histopathological examination showed the liver fibrosis S0 stage in 10 cases, S1 in 17 cases, S2 in 19 cases, S3 in 13 cases and S4 in 8 cases in our series; the APRI and LSM in patients with liver fibrosis S4 were(2.1±0.3) and (13.9±2.8)kPa, in S3 were (1.8±0.2) and (11.2±2.1)kPa, and in S2 were (1.5±0.2) and (7.6±1.5)kPa, all significantly higher than(1.1±0.2) and (6.1±1.2)kPa in S1 (P<0.05) or (0.8±0.1) and (4.0±0.5)kPa in S0 (P<0.05); the ROC analysis showed that the AUC was 0.950, with the sensitivity (Se) of 95.0% and the specificity (Sp) of 85.2%, when the APRI (with the cut-off-value of 1.5) and the LSM (with the cut-off-value of 7.5 kPa) were combined in predicting SLF, much superior to that by APRI(with the Se of 90.0% and the Sp of 81.5%) or by the LSM(with the Se of 75.0% and the Sp of 96.3%)diagnosis. Conclusion The combination of LSM and APRI might a high diagnostic efficacy in predicting SLF in patients with AIH, and warrants further clinical investigation.

Key words: Autoimmune hepatitis, Liver fibrosis, Aspartate aminotransferase/platelet ratio index, Transient ultrasound elastography, Diagnosis