Introduction: Liver biopsy is regarded as a gold standard in assessment of liver fibrosis in children with α₁-antitrypsin deficiency (ATD). Liver fibrosis due to viral infections and alcoholic liver disease can also be assessed by a non-invasive marker – APRI (AST-to-platelet ratio index). As prognosis and progression of liver disease in ATD are variable, non-invasive evaluation of liver fibrosis would be helpful.

Aim: To evaluate APRI as an indicator of advanced liver fibrosis in children with PiZZ phenotype of ATD.

Material and methods: Liver biopsy was performed in 45 patients aged 0.25 years (0.17-0.67 years), median (Q1-Q3). In all subjects APRI and liver histology were analyzed and compared. Liver fibrosis was assessed according to a 5-point scoring system (0-4). Points 2-4 were regarded as advanced fibrosis. Liver cirrhosis was also described. The best sensitivity and specificity of APRI were calculated based on receiver operating characteristic (ROC) analysis and area under curve (AUROC) was assessed.

Results: In the studied group APRI was 0.22 (0.12-0.39), median (Q1-Q3). In 21 children advanced fibrosis was recognized and in 6 patients liver cirrhosis was described. The optimal cut-off value for APRI for advanced fibrosis was 0.26, and for cirrhosis 0.33. Respectively for advanced fibrosis and cirrhosis, sensitivity was 0.60 (95% CI: 0.41-0.77), 0.83 (0.36-0.99); specificity was 0.87 (95% CI: 0.60-0.98), 0.31 (0.17-0.48); AUROC was 0.74 (95% CI: 0.58-0.89), 0.51 (95% CI: 0.28-0.74).

Conclusions: AST-to-platelet ratio index appears to be a sensitive but less specific indicator of cirrhosis in ATD and a valuable marker of advanced liver fibrosis.