Comparative value of controlled attenuation (CAPc) and continuous controlled attenuation (CAP) parameters for different stages of non-alcoholic fatty liver disease

Objective: To compare the efficacy of continuous controlled attenuation parameter (CAPc) compatible with vibration-controlled transient elastography (VCTE) versus standard controlled attenuation parameter (CAP) in a population of patients with non-alcoholic fatty liver disease (NAFLD). Materials and methods: A retrospective analysis of the database of patients (n = 582), divided into two groups: NAFLD group (n = 342) and control group (n = 240), was performed. The database was formed in the period from 2021 to 2023. The assessment of VCTE with CAP was carried out using two elastographs (FibroScan 530® and FibroScan 630 Expert®). The indicators of biochemical blood test, lipid and carbohydrate metabolism were evaluated. Statistical calculations were performed using STATISTICA13.0 (StatSoftInc., USA). Results: When comparing CAP with CAPc, statistical differences between CAP (264.7 ± 61.2) and CAPc (260.1 ± 57.4) (P 2 =0,87). The analysis showed high sensitivity and specificity of CAPc compared to CAP for S0 (85.2% and 88.5%) and S3 (81.2% and 91.2%) stages vs S1 (41.4% and 91.0%) and S2 (25.0% and 93.7%) stages. When analyzing mismatches, it was shown that the main share of mismatches falls within the interval between two adjacent stages (one for S0 and one for S3): S0: 10.7%, S1: 42.8%, S26 62.5% and S3: 10.0%. Conclusion: Since IQR CAPc is 3 times less than IQR CAP, CAPc has high diagnostic efficiency. On the other hand, CAPc and CAP scores are highly correlated, and the stages of liver steatosis calculated with CAPc and CAP are not statistically different, which indicates the equivalence of the results of two elastographs.