Novel urinary protein panels for the non‐invasive diagnosis of non‐alcoholic fatty liver disease and fibrosis stages

Abstract Background & Aims There is an unmet clinical need for non‐invasive tests to diagnose non‐alcoholic fatty liver disease (NAFLD) and individual fibrosis stages. We aimed to test whether urine protein panels could be used to identify NAFLD, NAFLD with fibrosis (stage F ≥ 1) and NAFLD with significant fibrosis (stage F ≥ 2). Methods We collected urine samples from 100 patients with biopsy‐confirmed NAFLD and 40 healthy volunteers, and proteomics and bioinformatics analyses were performed in this derivation cohort. Diagnostic models were developed for detecting NAFLD (UP NAFLD model), NAFLD with fibrosis (UP fibrosis model), or NAFLD with significant fibrosis (UP significant fibrosis model). Subsequently, the derivation cohort was divided into training and testing sets to evaluate the efficacy of these diagnostic models. Finally, in a separate independent validation cohort of 100 patients with biopsy‐confirmed NAFLD and 45 healthy controls, urinary enzyme‐linked immunosorbent assay analyses were undertaken to validate the accuracy of these new diagnostic models. Results The UP fibrosis model and the UP significant fibrosis model showed an AUROC of .863 (95% CI: .725–1.000) and 0.858 (95% CI: .712–1.000) in the training set; and .837 (95% CI: .711–.963) and .916 (95% CI: .825–1.000) in the testing set respectively. The UP NAFLD model showed an excellent diagnostic performance and the area under the receiver operator characteristic curve (AUROC) exceeded .90 in the derivation cohort. In the independent validation cohort, the AUROC for all three of the above diagnostic models exceeded .80. Conclusions Our newly developed models constructed from urine protein biomarkers have good accuracy for non‐invasively diagnosing liver fibrosis in NAFLD.