The development of noninvasive markers of liver fibrosis is a clinical and research priority. The aspartate aminotransferase-to-platelet ratio index (APRI) is a promising tool with limited expense and widespread availability. Our objective was to systematically review the performance of the APRI in hepatitis C virus (HCV)-infected patients. Random effects meta-analyses and areas under summary receiver operating characteristic curves (AUC) were examined to characterize APRI accuracy for significant fibrosis (stages 2-4) and cirrhosis. In 22 studies (n ؍ 4,266), the summary AUCs of the APRI for significant fibrosis and cirrhosis were 0.76 [95% confidence interval (CI), 0.74-0.79] and 0.82 (95%CI, 0.79-0.86), respectively. For significant fibrosis, an APRI threshold of 0.5 was 81% sensitive and 50% specific. At a 40% prevalence of significant fibrosis, this threshold had a negative predictive value (NPV) of 80%, but could reduce the necessity of liver biopsy by only 35%. For cirrhosis, a threshold of 1.0 was 76% sensitive and 71% specific. At a 15% cirrhosis prevalence, the NPV of this threshold was 91%. Higher APRI thresholds had suboptimal positive predictive values except in settings with a high prevalence of cirrhosis. APRI accuracy was not affected by the prevalence of advanced fibrosis, or study and biopsy quality. However, the accuracy for cirrhosis was greater in studies including human immunodeficiency virus (HIV)/HCV-co-infected patients. Conclusion: The major strength of the APRI is the exclusion of significant HCV-related fibrosis. Future studies of novel markers should demonstrate improved accuracy and cost-effectiveness compared with this economical and widely available index. (HEPATOLOGY 2007;46:912-921.)
C hronic hepatitis C virus (HCV) infection is a major public health problem, affecting an estimated 200 million individuals globally. 1 Although peginterferon and ribavirin treatment leads to a sustained virologic response in more than 50% of patients, only a minority are eligible or have access to therapy. 2 Thus, most are at risk of progressive liver fibrosis, which may lead to cirrhosis and complications including hepatocellular carcinoma and end-stage liver disease. 3 To estimate prognosis and guide management decisions, the accurate staging of hepatic fibrosis is a clinical and research priority. Currently, liver biopsy is the gold standard for this purpose. Unfortunately, this procedure is limited by invasiveness, complications, sampling error, variability in pathological interpretation, and the reluctance of patients to undergo repeated biopsies to monitor disease progression. 4,5 As antifibrotic therapies are developed, the latter will have important practical implications. 6 Because of these limitations, numerous investigators have examined alternative, noninvasive means of assessing hepatic fibrosis. A promising modality is transient elastography (FibroScan), which employs an ultrasound-based technique to measure the speed of propagation of elastic waves through the liver. 7 Unfortunately, this technology is costly (Ϸ $90,000 US) and limited to specialized centers. Serum biochemical tests, including direct and indi-