How Good Are Controlled Attenuation Parameter Scores from Fibroscan to Assess Steatosis, NASH, and Fibrosis?

Abstract

The objective of our study was to determine the concordance rates of steatosis staging by controlled attenuation parameter (CAP) scores from transient elastography (TE) in comparison with liver histology in patients with chronic liver disease and to determine the optimal CAP cutoffs to predict the severity of steatosis and identify those with nonalcoholic steatohepatitis (NASH). Patients (n = 217) who had both CAP scores and liver biopsy within a period of 90days were retrospectively studied. Histology was graded in a blinded fashion by a single pathologist; steatosis was graded on a scale from 0 to 3. Nonalcoholic fatty liver disease activity scores (NAS) scores were calculated for all patients. Optimal CAP cut-points were selected by maximum Youden's index. Area under receiver operating characteristic curve (AUROC) for CAP (using cutoff value ≥ 278dB/m) in differentiating steatosis 1-3 from 0 was 0.82 (95% CI 0.75-0.89), and 0.79 (95% CI 0.70-0.88) in differentiating steatosis 0-1 from 2 to 3 using CAP cutoff value ≥ 301dB/m. With CAP cutoff value ≥ 301dB/m, CAP identified NAS 3 or above with AUROC of 0.82 (95% CI 0.74-0.89). The AUROC for TE in differentiating fibrosis (cutoff 11.9kPa) 3-4 from 0 to 2 was 0.85 (95% CI 0.77-0.92), and 0.84 (95% CI 0.74-0.93) in differentiating (cutoff 14.4kPa) 4 from 0 to 3. Transient elastography is a good modality to accurately diagnose steatosis and NASH and can also differentiate advanced liver fibrosis from early stages.