Background: Controlled attenuation parameter (CAP) is a non-invasive method for diagnosing liver steatosis based on vibration-controlled transient elastography. The primary objective of this study was to assess CAP performance and determine the cut-off values for the diagnosis of hepatic steatosis in patients with chronic hepatitis B (CHB) using liver biopsy as a gold standard. The second objective was to apply the cut-off values found in the first cohort to a larger cohort to compare the performance of CAP and ultrasonography.
Methods: Overall, 189 patients with CHB who underwent liver biopsy and CAP detection and 1707 patients with CHB and CAP who underwent abdominal ultrasonography were prospectively enrolled. The performance of CAP for evaluating hepatic steatosis compared with liver biopsy was calculated using the area under the receiver operating characteristic curve (AUROC).
Results: In the 189 patients who underwent liver biopsy, the cut-offs for the CAP with steatosis S ≥ 1, S ≥ 2 and S ≥ 3 were 222 dB/m, 247 dB/m and 274 dB/m, respectively, and the AUROC were 0.88 (95% confidence interval [CI] = 0.82-0.95), 0.92 (95% CI = 0.87-0.97) and 0.94 (95% CI = 0.90-0.99), respectively. After applying the cut-offs above to the 1707 patients, it was found that CAP had a good concordance with abdominal ultrasonography with steatosis grade > S2. On multivariate analysis, body mass index (p < 0.001), triglyceride level (p < 0.001) and fasting glucose level (p = 0.001) were independent risk factors of CAP.
Conclusions: CAP had high diagnostic performance for evaluating hepatic steatosis in patients with CHB and had a good concordance with abdominal ultrasonography.
Keywords: CAP; abdominal ultrasonography; hepatic steatosis; laboratory examination.