Endocrine. 2022 Aug 18. doi: 10.1007/s12020-022-03157-x. Online ahead of print.
BACKGROUND: Controlled attenuation parameter (CAP) has been suggested as a new non-invasive measurement performed during transient elastography (TE) to assess liver steatosis. The aim of this study was to evaluate CAP values head to head with ultrasound (US) as reference standard.
METHODS: A consecutive cohort of patients attending abdominal US in an outpatient liver unit was included in this study with simultaneous CAP determination using the FibroScan® M probe and fibrosis scored by TE. Patients were subdivided in four groups on the basis of risk factors for Metabolically Associated Fatty Liver Disease (MAFLD).
RESULTS: Four hundred thirty-five patients were included in the analysis: 221 (51%) were male; 117 (26.9%) were in control group, 144 (33.1%) in group 2 with inactive HCV or HBV infection and at low-risk for MAFLD, 134 (30.8%) in group 3 at high-risk of MAFLD, 40 (9.2%) in group 4 at high-risk of MAFLD and concomitant inactive HCV or HBV infection. Liver steatosis detected with US evaluation was observed in the 41% of the entire cohort; in particular in the 3.4%, 20.1%, 83.6% and 87.4% of the group 1, 2, 3 and 4, respectively (p < 0.001). In patients at high-risk factor for MAFLD (group 3 and 4), CAP median levels were found statistically different among the severity-grading groups for US steatosis (S0 [n.27], ≥S1 [n.59], ≥S2 + S3 [n.89]), observing higher CAP levels in patients with a higher steatosis grade (≥S2 + S3 327.5 [±40.6] vs ≥S1 277.7 [±45.6] vs S0 245.1 [±47.4]; p < 0.001 for the whole cohort analysis) (p < 0.001 between ≥S2 + S3 and ≥S1) (p < 0.001 between ≥S2 + S3 and S0) (p = 0.004 between ≥S1 and S0). ROC analysis showed that the global performance of the CAP median level ≥ 258 to predict liver steatosis (S0 vs S1-3), was excellent with an Area Under the Curve (AUC) value of 0.87 [CI 95% 0. 835-0.904] with an 84% of sensitivity and a 78% of specificity, and a positive predictive value (PPV) of 73% and negative predictive value (NPV) of 88%. A TE-kPa median value <8.0 was detected in the 100%, 84%, 83.6% and 60% of patients in group 1, 2, 3 and 4, respectively. A TE-kPa median value >13.0 was detected in the 0%, 4.2%, 5.2% and 17.5% of patients in group 1, 2, 3 and 4, respectively.
CONCLUSIONS: CAP values are strongly associated with the standard US criteria for different degree of steatosis. Integrating TE up to 5% of patients may be identified at risk for advanced fibrosis.