Limited use of FIB-4 index in patients under 65 years of age with type 2 diabetes mellitus.

Objective: Screening for liver fibrosis holds significant importance in patients with type 2 diabetes mellitus (T2DM) due to their elevated risk of advanced hepatic fibrosis. However, it is recognized that the diagnostic performance of the Fibrosis-4 (FIB-4) index is relatively low in T2DM patients. Our study aims to explore the potential and limitations of utilizing FIB-4 as a screening tool in patients with T2DM.

Methods: A retrospective biopsy cohort of 1906 patients with biopsy-proven metabolic dysfunction-associated steatotic liver disease from South Korea, Japan, and Taiwan. Diagnostic performance according to T2DM was again compared after propensity score matching on age, sex, and body mass index.

Results: Patients with T2DM were significantly older than those without. The area under the receiver operating characteristic curve (AUROC) of FIB-4 for ruling out advanced fibrosis in non-T2DM patients was significantly higher than that of T2DM (0.821 vs. 0.761, p = 0.044). However, the AUROCs of FIB-4 according to the same age groups showed no significant difference between patients with T2DM and without (all p > 0.05). In the middle-aged group, the sensitivity of FIB-4 for ruling out advanced hepatic fibrosis was 77.1% for T2DM and did not differ with that of non-T2DM patients (73.0%) (p = 0.093). After propensity score matching of age, there was no statistically significant difference in the AUROCs of the T2DM and non-T2DM groups (0.860 vs. 0.761, p = 0.142).

Conclusions: Although the diagnostic performance of FIB-4 was found to be suboptimal in patients with T2DM, its limited use in individuals under 65 years of age with T2DM still holds value as a screening tool.