Noninvasive assessment of liver fibrosis with aspartate transaminase to platelet ratio index (APRI)

Adler M. Noninvasive assessment of liver fibrosis with aspartate transaminase to platelet ratio index (APRI). In chronic liver diseases, the management of patients must include a determination of the stage of fibrosis (to select specific therapies), a prognosis, the prevention of complications, and the surveillance of the disease. Over the past several years, significant progress has been made in improving noninvasive methods of assessing liver fibrosis. The risks of liver biopsy and the potential for sampling errors with regard to fibrosis staging support the use of noninvasive modalities including serum fibrosis markers or scores and elastography. The first are classified as direct (representing components of the extracellular matrix) or indirect (reflecting hepatic inflammation and function) and included in panels for clinical use. They include patented (i.e. Fibrotest, Fibrometer) and nonpatented (ASL/ALT ratio, APRI, FIB-4, Forns, ELF, Hepascore) tests. The majority of studies has involved patients with chronic HCV infection. Direct and indirect methods have demonstrated good to excellent performance in detecting significant disease (≥ F2) and cirrhosis (F4) (1). Transient elastography (Fibroscan®), which measures liver stiffness, has excellent accuracy in detecting cirrhosis (F4) in chronic liver diseases (2). The APRI (AST-to-platelet count ratio) is the most simple and cheapest indirect marker of inflammation and fibrosis (3). Its diagnostic performance in detecting advanced fibrosis has been evaluated extensively (4), showing low sensitivity (41%), low negative predictive values (64%), good specificity (95%) and high positive predictive values (88%). In a study, a group of Turkish investigators presented their experience with the APRI in patients with chronic liver disease (5). In a retrospective series of 455 patients (207 with HBV, 108 with HCV, and 140 with NAFLD) the low value (1) median Metavir fibrosis score with median values for APRI were reported 0.46, 0.49 and 0.43 respectively in the HBV, HCV and NAFLD groups. AUROC values for the detection of fibrosis (1 to 4) versus no fibrosis (F0) were 0.58, 0.54, and 0.62, respectively, in the 3 groups. Dr. Yilmaz and his team concluded that the APRI has acceptable accuracy in assessing liver fibrosis in patients with HCV and NAFLD but not in those with HBV. There are several drawbacks and flaws in this report that render its message unrealistic and erroneous. It was a retrospective series, without validation in an independent series, with 3 categories of etiologies, each