Background and aim: The validity of biomarkers of excessive alcohol drinking (EAD) (30 g/day or more), such as carbohydrate-deficient transferrin (CDT%), is confounded by liver disease severity. The aim was to improve the accuracy of the percentage of CDT by taking into account the presence of fibrosis and steatosis, estimated using biomarkers FibroTest and SteatoTest.
Methods: Three hundred and twenty consecutive patients, 97 with alcoholic liver disease (ALD), and 223 non-ALD, were included. In ALD, 58% had advanced fibrosis and 58% had steatosis; in non-ALD, 25% had advanced fibrosis and 25% had steatosis.
Results: The mean percentage of CDT was lower in ALD with advanced fibrosis [2.4 (SE=0.2)] versus without [4.1 (0.3) P<0.0001], and lower in ALD with steatosis versus without (2.4 vs. 3.9; P=0.0007). Among non-ALD, there was no difference in the percentage of CDT according to fibrosis or steatosis. gamma-glutamyl-transpeptidase was higher in patients with advanced fibrosis or with steatosis both in ALD and non-ALD. Aspartate aminotransferase/alanine aminotransferase (AST/ALT) was higher in ALD patients with fibrosis versus without (2.5 vs. 1.3 P<0.0001) but not in non-ALD (1.01 vs. 0.98). AST/ALT was higher in ALD patients with steatosis versus without (2.2 vs. 1.6 P=0.04) and the inverse was observed in non-ALD (0.6 vs. 1.1 P<0.0001). In the entire population the percentage of CDT, gamma-glutamyl-transpeptidase, AST/ALT was associated with EAD, the area under the receiver operating characteristic curve =0.89 (95% CI: 0.84-0.93), 0.93 (0.89-0.93) and 0.77 (0.71-0.82). An algorithm combining the percentage of CDT, FibroTest and SteatoTest permitted to obtain area under the receiver operating characteristic curve=0.92 versus 0.88 for the percentage of CDT (P=0.004) with 87.4% of patients classified correctly.
Conclusion: Biomarkers of EAD are confounded by fibrosis and steatosis. Accuracy of the percentage of CDT is significantly increased when combined with biomarkers of fibrosis and steatosis.