Gamma‐glutamyl transpeptidase dynamics as a biomarker for advanced fibrosis in non‐alcoholic fatty liver disease

It is unclear whether changes in lipid profile and liver biochemistry are associated with advanced fibrosis.Patients diagnosed with non-alcoholic fatty liver disease (NAFLD) between 2009 and 2017 were included. The changes in blood tests were calculated as follows: [(value at 6 months - value at baseline)/value at baseline] × 100. The endpoint was advanced fibrosis determined by the NAFLD fibrosis score, calculated every year from diagnosis until 2019. Cox proportional hazards models were used to identify factors predicting advanced fibrosis.After a median follow-up of 31.7 (19.4-50.8) months, advanced fibrosis occurred in 64 (6.3%) of 1021 patients. Gamma-glutamyl transpeptidase (GGT) levels (72.9 vs 51.1 IU/L; P = 0.23) and ΔGGT (+6.0% vs -6.9%; P = 0.06) were higher in the advanced fibrosis group. ΔGGT (hazard ratio [HR] 1.03; P < 0.001) was significantly associated with advanced fibrosis after adjusting for age and platelet count. The positive ΔGGT group showed a higher incidence of advanced fibrosis and the 1-standard deviation increment in ΔGGT showed a significant association with advanced fibrosis both in statin users (HR, 1.35) and in non-users (HR, 1.31; Ps < 0.05). The restricted cubic spline model identified a positive correlation between ΔGGT and the NAFLD fibrosis scores (P < 0.001). ΔGGT showed sensitivity of 64.2%, specificity of 52.6%, and negative predictive value of 98.3% in predicting advanced fibrosis.ΔGGT calculated at 6 months following NAFLD diagnosis is associated with advanced fibrosis.