Evaluation of controlled attenuation parameter in assessing hepatic steatosis in patients with autoimmune liver diseases

BACKGROUND: Hepatic steatosis commonly occurs in some chronic liver diseases and may affect disease progression. AIM: To investigate the performance of controlled attenuation parameter (CAP) for the diagnosis of hepatic steatosis in patients with autoimmune liver diseases (AILDs). METHODS: Patients who were suspected of having AILDs and underwent liver biopsy were consistently enrolled. Liver stiffness measurement (LSM) and CAP were performed by transient elastography. The area under the receiver operating characteristic (AUROC) curve was used to evaluate the performance of CAP for diagnosing hepatic steatosis compared with biopsy. RESULTS: Among 190 patients with biopsy-proven hepatic steatosis, 69 were diagnosed with autoimmune hepatitis (AIH), 18 with primary biliary cholangitis (PBC), and 27 with AIH-PBC overlap syndrome. The AUROCs of CAP for the diagnosis of steatosis in AILDS were 0.878 (0.791-0.965) for S1, 0.764 (0.676-0.853) for S2, and 0.821 (0.716-0.926) for S3. The CAP value was significantly related to hepatic steatosis grade (P < 0.001). Among 69 patients with AIH, the median CAP score was 205.63 ± 47.36 dB/m for S0, 258.41 ± 42.83 dB/m for S1, 293.00 ± 37.18 dB/m for S2, and 313.60 ± 27.89 dB/m for S3. Compared with patients with nonalcoholic fatty liver disease (NAFLD) presenting with autoimmune markers, patients with AIH concomitant with NAFLD were much older and had higher serum IgG levels and LSM values. CONCLUSION: CAP can be used as a noninvasive diagnostic method to evaluate hepatic steatosis in patients with AILDs. Determination of LSM combined with CAP may help to identify patients with AIH concomitant with NAFLD from those with NAFLD with autoimmune phenomena.