Novel non-invasive score to predict cirrhosis in the era of hepatitis C elimination: A population study of ex-substance users in Singapore.

BACKGROUND: Chronic hepatitis C infection is common among people with history of substance use. Liver fibrosis assessment is a barrier to linkage to care, particularly among those with history of substance users. The use of non-invasive scores can be helpful in predicting liver cirrhosis in the era of HCV elimination, especially in countries where transient elastography (TE) is not available. We compared the commonly used non-invasive scores with a novel non-invasive score in predicting liver cirrhosis in this population.

METHODS: HCV patients with history of substance use between 2011 and 2016 were analyzed. All patients had TE for liver fibrosis assessment. Clinical performance of established non-invasive scores for fibrosis assessment and novel score were compared. Youden's index was used to determine optimal cut-off of the novel score.

RESULTS: A total of 579 patients were included. In multivariate logistic regression, cirrhosis on TE was associated with age (P = 0.002), aspartate aminotransferase (AST) (P = 0.004), and platelet count (P < 0.001), but not alanine aminotransferase (ALT) (P = 0.896). These form the components of modified AST-to-platelet ratio index (APRI) score. Modified APRI was superior to APRI in predicting cirrhosis (AUROC, 0.796 vs. 0.770, P = 0.007), but not fibrosis-4 score (FIB-4) (P = 1.00). Modified APRI at cut-off of 4 has sensitivity, specificity and negative predictive value (NPV) of 94.4%, 26.9% and 92.6%, respectively, and at 19, has sensitivity, specificity and positive predictive value (PPV) of 33.3%, 96.2% and 77.1%, respectively. FIB-4 has a NPV and PPV of 88.6%, 41.8% and 78.5%, 77.6%, at cut-off of 1.45 and 3.25, respectively. Using the cut-off of 4 and 14 for modified APRI, 32.5% of patients can be correctly classified and misses out only 5.6% of cirrhosis patients.

CONCLUSIONS: Modified APRI score is superior in predicting cirrhosis in HCV population, with 32.5% of the population being correctly classified using cut-off of 4 and 14. Further studies are required to validate the findings.