Abstract: Objective To investigate the changes in alkaline phosphatase/platelet ratio (ALP/PLT) and the systemic immune inflammation index (SII) in patients with autoimmune hepatitis (AIH) and their clinical significance. Methods This study included 78 patients with AIH who were encountered in Hai'an People's Hospital between October 2021 and September 2024. After 6 months of treatment, biochemical response was assessed. The 62 patients with complete biochemical response were included in the complete group, and 16 patients with incomplete response were included in the incomplete group. ALP/PLT and SII were measured at admission and after treatment. SPSS statistical software was used for data analysis with the t-tests. P<0.05 was considered statistically significant. Applying the receiver operating characteristic (ROC) curves to evaluate the predictive value of the ALP/PLT ratio and systemic immune-inflammation index for treatment response in patients with AIH. Results The alanine aminotransferase (ALT) level in the complete group was (403.6 ± 44.8) U/L, higher than that in the incomplete group (359.7±59.5) U/L; the total bilirubin level was (351.9 ± 52.5) μmol/L, lower than that in the incomplete group (390.7±56.8) μmol/L, P<0.05. In the complete response group, ALP/PLT levels before and after treatment were (1.31 ± 0.11) and (0.73 ± 0.12), which were lower than the incomplete response group (1.51 ± 0.12 and 1.25 ± 0.14), P<0.05. Similarly, SII in the complete response group was (816.54 ± 103.59) before treatment and (645.28 ± 108.56) after treatment, lower than in the incomplete response group (951.40 ± 114.75 before treatment and 793.66 ± 93.72 after treatment), P<0.05. Logistic multivariate regression analysis showed that ALT, the degree of inflammation in the collecting area, TBil, ALP/PLT, and SII were all important factors in determining the biochemical response of the patients (P<0.05). ROC curve analysis showed that the AUC for ALP/PLT was 0.906, the AUC for SII was 0.805, indicating their higher diagnostic value. Conclusion ALP/PLT and the systemic immune inflammation index showed significant changes in AIH patients and were closely related to disease activity. They can be useful indicators for predicting biochemical responses and provide reference for clinical management.

Key words: Systemic immune inflammation index, Autoimmune hepatitis, Cirrhosis, Biochemical response, Predictive efficacy