Controlled attenuation parameter for non-invasive assessment of hepatic steatosis in Chinese patients

Abstract

Aim: To evaluate the performance of a novel non-invasive controlled attenuation parameter (CAP) to assess liver steatosis.

Methods: This was a multi-center prospective cohort study. Consecutive patients (aged ≥ 18 years) who had undergone percutaneous liver biopsy and CAP measurement were recruited from three Chinese liver centers. Steatosis was categorized as S0: < 5%; S1: 5%-33%; S2: 34%-66%; or S3: ≥ 67%, according to the nonalcoholic fatty liver disease (NAFLD) activity score. The FibroScan(®) 502 equipped with the M probe (Echosens, Paris, France) was used to capture both CAP and liver stiffness measurement values simultaneously. Receiver operating characteristic curves were plotted, and the areas under the curves were calculated to determine the diagnostic efficacy. The accuracy of the CAP values at the optimal thresholds was defined by maximizing the sum of sensitivity and specificity (maximum Youden index).

Results: A total of 152 patients were recruited, including 52 (34.2%) patients with NAFLD and 100 (65.8%) with chronic hepatitis B (CHB) virus infection. After adjustment, the steatosis grade (OR = 37.12; 95%CI: 21.63-52.60, P < 0.001) and body mass index (BMI, OR = 6.20; 95%CI: 2.92-9.48, P < 0.001) were found independently associated with CAP by multivariate linear regression analysis. CAP was not influenced by inflammation, fibrosis or aetiology. The median CAP values and interquartile ranges among patients with S0, S1, S2 and S3 steatosis were 211 (181-240) dB/m, 270 (253-305) dB/m, 330 (302-360) dB/m, and 346 (313-363) dB/m, respectively. The cut-offs for the CAP values in all patients with steatosis ≥ 5%, ≥ 34% and ≥ 67% were 253 dB/m, 285 dB/m and 310 dB/m, respectively. The areas under the curves were 0.92, 0.92 and 0.88 for steatosis ≥ 5%, ≥ 34% and ≥ 67%, respectively. No significant differences were found in the CAP values between the NAFLD group and the CHB group in each steatosis grade.

Conclusion: CAP appears to be a promising tool for the non-invasive detection and quantification of hepatic steatosis, but is limited by BMI.

Keywords: Chronic hepatitis B; Controlled attenuation parameter; Fatty liver; Nonalcoholic; Transient elastography.

Figures

Figure 1

Controlled attenuation parameter distribution for different steatosis grades or body mass index levels. A: Controlled attenuation parameter distribution in patients with different steatosis grades (n = 152); B: CAP distribution in patients with different BMI levels (n = 152); C: CAP distribution in patients with BMI levels with either no steatosis or steatosis less than 5% (n = 63); D: CAP between NAFLD and CHB patients with the same degree of fatty deposition (n = 89). 1Fisher’s exact test was used; 2No NAFLD patients in S0. CAP: Controlled attenuation parameter; BMI: Body mass index; NAFLD: Non-alcoholic fatty liver disease; CHB: Chronic hepatitis B.

Figure 2

Receiver operating characteristic curves. A: Receiver operating characteristic curve for controlled attenuation parameter in the diagnosis of hepatic steatosis ≥ 5%, ≥ 34% and ≥ 67%; B: Receiver operating characteristic curves and area under the curves (AUCs) between two steatosis grades. Se: sensitivity; Sp: specificity.