Role of AST to platelet ratio index in the detection of liver fibrosis in patients with recurrent hepatitis C after liver transplantation

Background and Aim: Per protocol annual liver biopsy represents the gold standard in the assessment of graft fibrosis progression due to recurrent hepatitis C after liver transplantation. Non-invasive liver fibrosis tests have been proposed as surrogate markers of liver fibrosis in hepatitis C virus (HCV)-positive immune-competent patients. No data are available in the literature on the usefulness of non-invasive liver fibrosis tests in liver transplanted patients with recurrent HCV infection. Methods: A total of 102 annual per protocol liver biopsies performed in 51 consecutive HCV-positive recipients (31 men), with a follow-up period lasting up to 5 years, were included and evaluated in this study. At each time point, the following non-invasive liver fibrosis tests were calculated: aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio, age-platelet index, AST to platelet ratio index (APRI), Forns' fibrosis index and Bonacini's discriminant score. Results: In discriminating patients with histological fibrosis score > 2, APRI provided the best area under the receiver operating characteristic curves (AUROC) (0.801), in comparison to the other four non-invasive liver fibrosis tests. The AUROC of APRI was better in female (0.871) than in male (0.753) recipients. Among female recipients, an APRI value > 1.4 was 91% sensitive and 75% specific in detecting a staging score > 2. The corresponding values among male recipients were 60% and 77%, respectively. Conclusions: Among non-invasive liver fibrosis tests, APRI has the highest diagnostic value in discriminating liver transplanted patients with progression to significant liver fibrosis, although its accuracy is influenced by recipient sex.