Novel controlled attenuation parameter for noninvasive assessment of steatosis using Fibroscan(®): validation in chronic hepatitis C

Abstract

A novel controlled attenuation parameter (CAP) has been developed for Fibroscan(®) to assess liver steatosis, simultaneously with liver stiffness measurement (LSM). We assessed CAP diagnostic accuracy in a large cohort of patients with chronic hepatitis C (CHC) virus. A total of 615 patients with CHC, who underwent both Fibroscan(®) and liver biopsy, were analysed. Fibrosis was graded using METAVIR score. Steatosis was categorized by visual assessment as S(0) : steatosis in <10% of hepatocytes, S(1) : 11-33%, S(2) : 34-66% and S(3) : 67-100%. Performances of CAP and liver stiffness were determined using receiver operating characteristic (ROC) curve analysis and cross-validated using the bootstrap method. The Obuchowski measure was used to assess overall accuracy of CAP and to differentiate between steatosis grades. In multivariate analysis, CAP was related to steatosis (P < 10(-15) ) independently of fibrosis stage (which was related to LSM). The areas under ROC curves using CAP to detect steatosis were 0.80 (95% CI, 0.75-0.84) for S ≥ S(1) , 0.86 (0.81-0.92) for S ≥ S(2) and 0.88 (0.73-1) S = S(3) . CAP exhibited a good ability to differentiate steatosis grades (Obuchowski measure = 0.92). Performance of LSM for fibrosis assessment confirmed results from previous studies. CAP is a novel tool to assess the degree of steatosis and both fibrosis and steatosis can be evaluated noninvasively during the same procedure using Fibroscan(®) , in patients with CHC.