Objective: To investigate the value of controlled attenuation parameter (CAP) in the diagnosis of fatty liver using FibroScan in patients with chronic liver disease (CLD).
Methods: A prospective cohort study was performed for the patients with chronic hepatitis B (CHB), chronic hepatitis C (CHC), and non-alcoholic fatty liver disease (NAFLD) who underwent liver pathological examination followed by CAP measurement within 1 week in The Second People's Hospital of Tianjin from February 2013 to May 2014. According to related guidelines, hepatocyte steatosis was classified as S0: <5%, S1: 5%-33%, S2: 34%-66%, or S3: ≥67%. The receiver operating characteristic (ROC) curves were plotted with positive results as the diagnostic criteria, and the optimal cut-off values were determined at the maximum Youden index. Single linear regression and multiple stepwise regression were applied to analyze the influencing factors for CAP.
Results: A total of 427 patients were enrolled, consisting of 19 patients (4.4%) with NAFLD, 383 (89.7%) with CHB, and 25 (5.9%) with CHC. The optimal cut-off values for CAP in the diagnosis of steatosis ≥5%, ≥34%, and ≥67% were 230 dB/m, 252 dB/m, and 283 dB/m, respectively, and the areas under the ROC curve were 0.803, 0.942, and 0.938, respectively (Z = 14.194, 28.385, and 16.486, respectively, all P < 0.01). CAP differentiated S0 from S1, S1 from S2, S0 from S2, S0 from S3, and S1 from S3 (Z = 10.109, 10.224, 47.81, 29.917, and 10.999, all P < 0.01), but was not able to differentiate S2 from S3 (Z = 0.656, P = 0.5116). The single linear regression and multiple stepwise regression analyses showed that only body mass index (BMI; B = 4.001, P < 0.01) and hepatic steatosis (B = 33.015, P = 0.000) were correlated with CAP. The coincidence rates between CAP and liver pathological diagnosis were 77.4%, 81.0%, and 96.2% for S0, S3, and ≥S2, respectively.
Conclusion: CAP has a good value in the diagnosis of fatty liver in CLD patients, and can well differentiate between all stages of fatty liver except S2 and S3. CAP is influenced by BMI, but is not found to be associated with liver fibrosis, inflammation, liver stiffness measurement, and etiology.