Serum β-klotho is a potential biomarker for diagnosing alcoholic liver disease and differentiating from nonalcoholic fatty liver disease.

Background: Alcoholic liver disease (ALD), with the control of infectious liver disease and the improvement in living standards, is emerging as a significant liver disease posing a threat to public health. Besides, ALD often overlaps or coexists with nonalcoholic fatty liver disease (NAFLD), however, due to the lack of specific non-invasive biomarkers and the fact that drinkers' self-reported alcohol consumption is often concealed, the identification of ALD and NAFLD is sometimes not easy. This study aims to explore a new specific serum biomarker to more easily diagnose ALD and differentiate it from NAFLD.

Subjects And Methods: A total of 204 serum samples were collected, including 70 from ALD patients, 68 from NAFLD patients and 66 from healthy controls (HC). Serum β-klotho (sKLB) levels were measured using the enzyme-linked immunosorbent assay (ELISA). The diagnostic performance of potential biomarkers was evaluated using the area under the receive operating characteristic curve (AUROC).

Results: The levels of sKLB were significantly elevated (1,332.12 (410.40, 2,687.00) pg/mL, < 0.001) in ALD patients and significantly reduced in NAFLD patients (47.82 (32.76, 77.11) pg/mL, = 0.018) compared to the healthy controls. The AUROC for sKLB in diagnosing ALD is 0.927, which was higher than that for the aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (0.672) and γ-glutamyl transpeptidase (GGT) (0.891). The combined AUROC for sKLB + AST/ALT, sKLB + GGT, and AST/ALT ratio + GGT in diagnosing ALD were 0.924, 0.967 and 0.917, respectively.

Conclusion: sKLB is a potential biomarker for diagnosing ALD, and may aid in differentiating between ALD and NAFLD, when combined with GGT, sKLB offers enhanced diagnostic sensitivity and specificity for ALD.