Accuracy of FibroScan Controlled Attenuation Parameter and Liver Stiffness Measurement in Assessing Steatosis and Fibrosis in Patients With Non-alcoholic Fatty Liver Disease.

Abstract

BACKGROUND & AIMS: We estimated the accuracy of FibroScan vibration-controlled transient elastography controlled attenuation parameter (CAP) and liver stiffness measurements (LSMs) in assessing steatosis and fibrosis in patients with suspected NAFLD. METHODS: We collected data from 450 consecutive adults who underwent liver biopsy analysis for suspected NAFLD at 7 centers in the United Kingdom from March 2014 through January 2017. FibroScan examinations with M or XL probe were completed within the 2 weeks of the biopsy analysis (404 had a valid examination). The biopsies were scored by 2 blinded expert pathologists according to non-alcoholic steatohepatitis clinical research network criteria. Diagnostic accuracy was estimated using the area under the receiver operating characteristic curves (AUROC) for the categories of steatosis and fibrosis. We assessed effects of disease prevalence on positive and negative predictive values. For LSMs, the effects of histological parameters and probe type were appraised using multivariable analysis. RESULTS: Using biopsy analysis as the reference standard, we found that CAP identified patients with steatosis with an AUROCs of 0.87 (95% CI, 0.82-0.92) for S≥S1, 0.77 (95% CI, 0.71-0.82) for S≥S2, and 0.70 (95% CI, 0.64-0.75) for S=S3. Youden cut-off values for S≥S1, S≥S2 and S≥S3 were 302 dB/m, 331 dB/m, and 337 dB/m respectively. LSM identified patients with fibrosis with AUROCs of 0.77 (95% CI, 0.72-0.82) for F≥F2, 0.80 (95% CI, 0.75-0.84) for F≥F3, and 0.89 (95% CI, 0.84-0.93) for F=F4. Youden cut-off values for F≥F2, F≥F3 and F=F4 were 8.2 kPa, 9.7 kPa, and 13.6 kPa respectively. Applying the optimal cut-off values, determined from this cohort, to populations of lower fibrosis prevalence increased negative predictive values and reduced positive predictive values. Multivariable analysis found that the only parameter that significantly affect LSMs was fibrosis stage (P<10-16); we found no association with steatosis or probe type. CONCLUSIONS: In a prospective analysis of patients with NAFLD, we found CAP and LSMs by FibroScan to assess liver steatosis and fibrosis, respectively, with AUROC values ranging from 0.7 to 0.89. Probe type and steatosis did not affect LSMs.