Poor Diagnostic Efficacy of Noninvasive Tests for Advanced Fibrosis in Obese or Younger Than 60 Diabetic NAFLD patients

Abstract

Background & aims: Serum-based noninvasive tests (NITs) have been widely used to assess liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). However, the diagnostic efficacy of NITs across ranges of age, body mass index (BMI), and presence of type 2 diabetes (T2DM) may vary and have not been well-characterized.

Methods: We analyzed 1489 patients with biopsy-proven NAFLD from 6 centers in Japan, Taiwan, and Korea. Using histology as the gold standard, we compared the areas under the receiver operating characteristic (AUROCs) of Fibrosis-4 index (FIB-4), NAFLD fibrosis score (NFS), and the new Hepamet fibrosis score (HFS), with a focus on performance in subgroups as stratified by age, BMI, and the presence of T2DM.

Results: By histology, 44.0% of the overall cohort (655/1489) had F2-4, and 20.6% (307/1489) had F3-4 fibrosis. FIB-4 had the highest AUROCs for both F2-4 (0.701 vs NFS 0.676 and HFS 0.682, P = .001) and F3-4 (0.767 vs NFS 0.736 and HFS 0.752, P = .002). However, for F3-4 fibrosis, the AUROCs of all 3 NITs were generally higher in older (>60 years), nonobese (BMI <25 kg/m²), and non-diabetic patients, although overall the best performance was observed with FIB-4 among nonobese (BMI<25) diabetic patients (AUROC, 0.92). The worst performance was observed in younger patients with T2DM for all NITs including FIB-4 (AUROC, 0.63-0.66).

Conclusions: FIB-4 had higher diagnostic efficacy for F3-4 than NFS or HFS, but this varied greatly by age, BMI, and T2DM, with better performance in older, nonobese, and nondiabetic patients. However, all NITs including FIB-4 had unacceptably poor performance in young or obese diabetic patients.

Keywords: FIB-4 Index; Hepamet Fibrosis Score; NITs; Nonalcoholic Fatty Liver Disease.