Discordance among transient elastography, aspartate aminotransferase to platelet ratio index, and histologic assessments of liver fibrosis in patients with chronic hepatitis C.

BACKGROUND & AIMS: Liver biopsy is the standard for assessing hepatic fibrosis. Ultrasound transient elastography (TE) and the aspartate aminotransferase to platelet ratio index (APRI) are validated, noninvasive tests for identifying patients with cirrhosis. We evaluated discordance among TE, APRI, and histology diagnoses of cirrhosis.

METHODS

We analyzed findings from 109 patients with chronic hepatitis C who underwent TE within 6 months of liver biopsy at the US National Institutes of Health from 2006 to 2011. Fibrosis was scored using the Ishak scale (0-6). APRI scores were calculated using data collected on the day of the biopsy. Area under receiver operator characteristic curves for TE and APRI were calculated to distinguish patients with cirrhosis (Ishak scores, 5-6) from those without cirrhosis (Ishak scores, 0-4). The best cut-off value and corresponding positive predictive value (PPV) and negative predictive value (NPV) were selected.

RESULTS

Based on biopsy analysis, 18% of the patients had no fibrosis, 52% had mild fibrosis, 17% had bridging fibrosis, and 13% had cirrhosis. A TE cut-off value of 13.1 kPa identified patients with cirrhosis with the highest level of accuracy (100% sensitivity, 89% specificity, 58% PPV, 100% NPV), as did an APRI cut-off value of 1.0 (79% sensitivity, 78% specificity, 34% PPV, 96% NPV). Results from TE and APRI were discordant for 28% of cases. TE identified all cases of cirrhosis and an additional 10 patients who were not found to have cirrhosis based on histology analysis; 7 of these patients had clinical or radiologic evidence of cirrhosis, indicating that the biopsy sample was not staged correctly.

CONCLUSIONS

TE increases the accuracies of biopsy and APRI analyses in identifying patients with cirrhosis. TE also might be used to screen patients for cirrhosis and identify those who should be followed up for development of hepatocellular carcinoma and varices.