Value of fibrosis-4 index in diagnosis of liver fibrosis in autoimmune hepatitis

Objective To investigate the value of the noninvasive diagnostic model of liver fibrosis fibrosis-4 ( FIB-4) index in the diagnosis of liver fibrosis in autoimmune hepatitis ( AIH) through an analysis of the clinical data of AIH patients. Methods A retrospective analysis was performed for the clinical data of 71 AIH patients who were hospitalized in Beijing Ditan Hospital, Capital Medical University from January 2010 to December 2015 and underwent liver biopsy, including age, alanine aminotransferase ( ALT) , aspartate aminotransferase ( AST) , and platelet count ( PLT) . FIB-4 index was calculated and its correlation with pathological staging of liver fibrosis was analyzed, as well as the specificity and sensitivity of FIB-4 index in the diagnosis of liver fibrosis in AIH patients. The Kruskal-Wallis H test was used for comparison of continuous data between groups. Spearman correlation analysis was also performed. The receiver operating characteristic ( ROC) curve was plotted and the area under the ROC curve ( AUC) was analyzed. Results There was a significant difference in FIB-4 index between patients with different stages of liver fibrosis ( χ2= 10. 134, P = 0. 038) , but there were no significant differences in age, ALT, AST, and PLT between these patients ( all P > 0. 05) . FIB-4 index was positively correlated with fibrosis degree and increased with the increase in fibrosis degree ( rs= 0. 338, P = 0. 004) , while PLT was negatively correlated with fibrosis degree ( rs=-0. 305, P =0. 010) . In the diagnosis of S≥1, S≥2, and S≥3 liver fibrosis in AIH, FIB-4 index had AUCs of 0. 603 ( P = 0. 408) , 0. 698 ( P =0. 004) , and 0. 704 ( P = 0. 049) , respectively. FIB-4 had relatively low sensitivity and specificity for the diagnosis of S≥1 liver cirrhosis, but had a relatively high sensitivy for the diagnosis of S≥2 liver cirrhosis ( 77. 4%) and S≥3 liver fibrosis ( 88. 9%) . Conclusion FIB-4 index does not have a significant value in evaluating liver fibrosis in patients without liver fibrosis or with mild liver fibrosis, while it has a high value in the diagnosis of marked ( S≥2) and severe ( S≥3) liver fibrosis. It has better results in the diagnosis of severe liver fibrosis than marked liver fibrosis.