A simple scoring system using type IV collagen 7S and aspartate aminotransferase for diagnosing nonalcoholic steatohepatitis and related fibrosis.

BACKGROUND: Recently we reported novel noninvasive scoring systems for diagnosing nonalcoholic steatohepatitis (NASH) and related fibrosis, namely FM-NASH index and FM-fibro index. They are highly accurate, however, they contain some items not widely used in clinical practice and require six or more items to diagnose both NASH and related fibrosis. By focusing on widely used items, we tried to identify convenient markers in common with the both diagnoses.

METHODS: To explore the markers for NASH and related fibrosis in nonalcoholic fatty liver disease (NAFLD) patients, we used data of 24 clinical items in our previous report. By logistic regression analysis, we identified items suitable for the both diagnoses. We then evaluated their accuracies by area under the receiver operator characteristic curves (AUROCs) on independent validation data.

RESULTS: We identified the combination of type IV collagen 7S and aspartate aminotransferase (AST) as the predictor both for NASH and related fibrosis. We developed a scoring system based on the combination and evaluated the prediction accuracy: the AUROCs for training/validation data sets are 0.857/0.769 for NASH and 0.918/0.842 for NASH-related fibrosis. The former was higher than that of NAFIC score, and the latter was higher than those of existing fibrosis markers: BARD score, FIB-4 index and NAFLD fibrosis score but lower than FM-fibro index.

CONCLUSIONS: The scoring system using type IV collagen 7S and AST named CA index can predict both NASH and related fibrosis in NAFLD patients with sufficient accuracy and could be a convenient diagnostic and screening tool for NASH and related fibrosis. The scoring system needs to be validated in independent larger populations from multiple clinical centers.