Transient Elastography and Serum-Based Tests for Diagnosis of Fatty Liver and Advanced Fibrosis in a Community Cohort: A Cross-Sectional Analysis.

Background: Noninvasive tests (NITs) are necessary for knowing the true prevalence of fatty liver (FL) and advanced fibrosis. NITs for diagnosis of FL and fibrosis were compared.

Methods: Data were obtained from the National Health and Examination Survey (2017-2018). Participants were excluded with other liver diseases, missing data for NIT calculation, and/or excessive alcohol use. Area under the receiver operating characteristic (AUROC) compared the accuracy of 4 FL NITs (CAP, HSI, FLI, USFLI) among themselves and to CAP value of 285 dB/m and 5 fibrosis NITs (transient elastography, APRI, NFS, FIB-4, HEPAmet) among themselves and to LSM ≥8.7 kPa.

Results: Among 2,051 participants (average age 47 (±17.7), 48% males, 62% white, 73% overweight/obese, 39% metabolic syndrome), demographics were similar among NIT groups (CAP = 812; HSI = 1,234; FLI = 935; USFLI-824). FL prevalence by NIT: 39% CAP, 58% HSI, 47% FLI, 37% USFLI. Advanced fibrosis prevalence by test: LSM (≥8.7 kPa) 10-14%; FIB-4 (≥2.67) and APRI (≥0.7) 1.3-2.7%; HEPAmet (>0.47) 14-21%. Compared to CAP ≥285, FLI (AUROC = 0.823) and USFLI (AUROC = 0.833) performed better than HSI (AUROC: 0.798). Compared to LSM ≥8.7 kPa, only NFS (AUROC = 0.722) performed well (FIB-4 AUROC = 0.606; APRI = 0.647; HEPAmet = 0.629). Among the CAP cohort, the strongest FL predictor was obesity (OR: 15.2, 95% CI: 7.97-28.9, p < 0.001); the only fibrosis predictor was elevated AST (OR: 1.06, 95% CI: 1.00-1.12, p = 0.04). The addition of CAP or LSM as a second NIT reduced the number of indeterminate patients especially for FL.

Conclusions: Regardless of diagnostic method in 2017-2018, the prevalence of NAFLD was >35%. NITs for FL performed well but not for advanced fibrosis. CAP and LSM as a second NIT reduced those considered indeterminate.