Cytokeratin 18 fragment is associated with steatosis-associated fibrosis estimator score and lipid in patients with steatotic liver disease.

BACKGROUND: Serum cytokeratin 18 fragment (CK18F) has been developed as a new non-invasive test (NIT) for risk assessment of steatotic liver disease (SLD); however, there are few reports on its relationship with existing NITs and association with cardiometabolic risk factors (CMRFs). AIM: To clarify the relationship among CK18F, NITs, and CMRF. METHODS: We included 125 patients who were assessed for SLD and had CK18F measured in cross-sectional study. The fibrosis-4 index (FIB-4), steatosis-associated fibrosis estimator (SAFE) score, liver stiffness (LS), controlled attenuation parameter, and FibroScan-aspartate aminotransferase (FAST) score were compared with CK18F as existing NITs. RESULTS: CK18F was associated with aspartate aminotransferase, alanine aminotransferase, and triglyceride (TG). FAST and SAFE score were associated with high CK18F (> 260 U/L), but not FIB-4 or LS. The cut-off values for TG and high-density lipoprotein (HDL) cholesterol used to determine high CK18F using receiver operating characteristics analysis were 126 mg/dL and 56 mg/dL respectively. High TG (> 126 mg/dL) and low HDL (< 56 mg/dL) were associated with high CK18F. The risk of high CK18F was higher when high TG and low HDL were combined than when each was present alone. CMRF was higher in the high CK18F group, but was not associated with CK18F levels. However, when the TG and HDL criteria for CMRF were replaced by TG > 126 mg/mL and HDL < 56 mg/dL, modified CMRF (mCMRF) was associated with CK18F levels, with a higher risk of high CK18F than CMRF. CONCLUSION: CK18F is a new NIT associated with SAFE score and FAST. High TG, low HDL, and mCMRF are associated with high CK18F.