We read with interest the article by Wai et al.1 on the use of the aspartate aminotransferase to platelet ratio index (APRI) for the noninvasive diagnosis of liver fibrosis. The authors concluded that APRI can identify with a high degree of accuracy patients who have chronic hepatitis C with significant fibrosis, and application of this index may decrease the need for staging liver biopsy specimens among these patients.
We therefore determined APRI after an overnight fast in 71 children (age range 4-17 years; mean age 10 years; mean alanine aminotransferase 83 IU/L) with biopsy-verified chronic hepatitis Be antigen– and HBV DNA–positive hepatitis B prior to antiviral treatment. Children infected with hepatitis C virus (HCV) and diagnosed liver cirrhosis were excluded from this study. Protocol was approved by the ethics committee of the Medical University of Bialystok. APRI was calculated according to Wai et al.1 Fibrosis stage was assessed in a blinded fashion according to Ishak et al.2 by a single pathologist. We defined advanced liver fibrosis as a score >2. Receiver-operating characteristics analysis was used to calculate the power of the index to detect advanced liver fibrosis (AccuROC, Accumetric Corp., Montreal, Canada).
Thirty-four children (48%) had advanced fibrosis. The ability of APRI was significant (P = 0.0003) in differentiating children with advanced liver fibrosis from those with mild fibrosis: area under the curve (95% CI) = 0.748 (0.63-0.87); positive predictive value = 70.3%; negative predictive value = 76.5%. APRI > 0.59 had a sensitivity of 76.5% and a specificity of 70% (Fig. 1). Correct classification proportion of staging fibrosis was 73.2%; therefore, 52 of 71 children could be correctly allocated to either the group with mild or advanced fibrosis, potentially avoiding biopsy. Other serum parameters—e.g., aspartate to alanine aminotransferase ratio (AAR) or platelet count—yielded a lower predictive power (area under the curve = 0.395 and 0.346, respectively).
Liver biopsy is thought mandatory for the management of patients with chronic hepatitis B virus (HBV) infection, especially for staging fibrosis. However, noninvasive markers that predict advanced fibrosis due to chronic hepaititis B in children are lacking, except in our previous studies. Among the panel of examined serum fibrosis markers (n = 11), only hyaluronan and laminin-2 accurately predicted the presence of advanced fibrosis.3–5 However, extracellular matrix components are not routinely used in clinical practice in contradiction to APRI, which can be calculated without additional blood collection or costs and is not influenced by body growth.
Data regarding assessment of APRI in adults are also scarce. Our results are in agreement with the data presented by Wai et al.1 and Berg et al.,6 but Giannini and Testa,7 Le Calvez et al.,8 and Castera et al.9 found that AAR7 and Fibrotest8, 9 are more accurate than APRI for noninvasive assessment of significant fibrosis. The usage of different histological scoring systems, interobserver or intraobserver variability of the biopsies, and differences between the patient populations in these studies could be responsible for this disagreement.
We conclude that APRI may be an accurate, inexpensive, and simple noninvasive index in predicting advanced liver fibrosis in children with chronic hepatitis B. Application of this index may decrease the need for liver biopsy in children with chronic hepatitis B, but further studies are urgently needed to confirm this finding.