Predictive value of cytokeratin-18 fragment levels for diagnosing steatohepatitis in patients with nonalcoholic fatty liver disease

Several noninvasive markers have been developed to predict nonalcoholic steatohepatitis (NASH). We investigated the predictive value of the cytokeratin-18 fragment (CK18-F) level and FIB-4 index for diagnosing NASH in patients with nonalcoholic fatty liver disease (NAFLD).A total of 246 patients histologically diagnosed with NASH (n = 185) or nonalcoholic fatty liver (n = 61) were enrolled. We analyzed weighted receiver operating characteristic (ROC) curves for the prediction of NASH and determined the relationship between the CK18-F level and the histological features of NASH. In addition, we investigated the predictive value of the combination of the CK18-F level and FIB-4 index for diagnosing NASH.The area under the ROC curve (AUROC) value of the CK18-F level was 0.77. With a CK18-F cutoff level of 260 U/L, the sensitivity and specificity for diagnosing NASH were 82.7 and 57.4%, respectively. Multiple comparisons showed that the CK18-F level did not differ among fibrosis stages but did significantly differ among hepatocyte ballooning grades. Overall, 95.7% (66/69) of patients with a FIB-4 index of ≥2.67 had NASH. In patients with a FIB-4 index of <2.67, the AUROC value of the CK18-F level for predicting NASH was 0.77 and a CK18-F cutoff level of 260 U/L resulted in a sensitivity and specificity of 82.4 and 56.9%.The CK18-F level had a good predictive ability for diagnosing NASH in patients with NAFLD. Additionally, the combination of the CK18-F level and FIB-4 index accurately and noninvasively predicted NASH, even those with a low FIB-4 index.