Liver stiffness assessed by transient elastography as a potential indicator of chronic kidney disease in patients with nonalcoholic fatty liver disease.

BACKGROUND: This study was designed to determine the diagnostic value of liver stiffness measured by transient elastography (TE) in identifying chronic kidney disease (CKD) in individuals with ultrasonography-diagnosed NAFLD.

METHODS: A total of 1439 adult patients with ultrasonography-diagnosed NAFLD between October 2015 and August 2017 in China-Japan union hospital of Jilin university were initially eligible. According to the exclusion criteria, 24 patients were excluded, and eventually, a total of 1415 patients were included in the study. The AST/ALT ratio and FIB-4 score were calculated from blood tests, and liver stiffness was measured using TE.

RESULTS: The liver stiffness measured by TE, FIB-4 score, ALT/AST ratio were significantly elevated in CKD patients, compared with those without CKD (P < 0.001). The areas under the curve (AUROC) of liver stiffness, FIB-4 score and AST/ALT ratio were 0.694 (0.670-0.718), 0.707 (0.682-0.730), 0.712 (0.688-0.736), showing no statistically significant difference between these three tests. Further, multivariate analysis identified four independent risk factors for CKD: age, diabetes mellitus, serum uric acid, and liver stiffness. Also, the performance of these four independent variables taken together in a logistic regression model for identifying CKD was 0.834 (AUROC; 95%CI: 0.814-0.853), showing a higher diagnostic performance than that of a single application of liver stiffness.

CONCLUSIONS: Liver stiffness assessed by TE is a potential indicator for CKD in ultrasonography-diagnosed NAFLD patients. Further, a four-variable model (liver stiffness, age, serum uric acid, and diabetes mellitus) could be a useful tool for identifying subjects at high risk for CKD in NAFLD patients.