Background: Non-alcoholic steatohepatitis (NASH) can lead to cirrhosis and hepatocellular carcinoma. The NASH fibrosis score (NFS) has proven to be a reliable, non-invasive marker for prediction of advanced fibrosis. Aspartate aminotransferase-to-platelet ratio index (APRI) is a simpler calculation than NFS, but has never been studied in patients with non-alcoholic fatty liver disease (NAFLD).
Aim: To validate APRI as a non-invasive marker of liver fibrosis in subjects with NAFLD to be used in clinical practice.
Design/methods: The cohort consisted of 111 patients with histological diagnoses of NAFLD. The biopsy samples were staged and graded according to the NASH clinical research network (CRN) criteria. These were grouped into fatty liver disease (FLD), NASH, no/mild fibrosis, and advanced fibrosis. The sensitivity and specificity of APRI were compared with NFS and aspartate aminotransferase-to-alanine aminotransferase (AST/ALT) ratio.
Results: The APRI was significantly higher in the advanced fibrosis group. The area under receiver operating characteristic (ROC) curve for APRI was 0.85 with an optimal cut-off of 0.98, giving a sensitivity of 75% and a specificity of 86%. The NFS was significantly lower in the advanced fibrosis group. The ROC for NFS gave an area under curve (AUC) of 0.77 and a cut-off value of -1.3 with a sensitivity of 76% and specificity of 69%. The positive predictive value for APRI was 54% as opposed to 34% for NFS. The negative predictive value was 93% for APRI and 94% for NFS.
Conclusion: APRI compared favourably to NFS and was superior to AST/ALT for the prediction of advanced fibrosis. We therefore propose the use of APRI in a new algorithm for the detection of advanced fibrosis.