Diabetes and central adiposity are associated with elevated liver stiffness despite low fibrosis-4 index in adults at metabolic risk

AIMS: To estimate how often elevated liver stiffness occurs despite a low fibrosis-4 index using age-stratified cutoffs (FIB-4) in adults at metabolic risk and whether diabetes and central adiposity characterize this discordant subgroup. METHODS: We performed a cross-sectional analysis of prospectively collected baseline data from a metabolic-risk screening programme. Adults aged ≥ 35 years with recorded FIB-4 and quality-confirmed vibration-controlled transient elastography were included. Low FIB-4 was < 1.3 at age 35-64 years and < 2.0 at age ≥ 65 years. The outcome was liver stiffness measurement (LSM) ≥ 8 kPa. RESULTS: Among 351 participants, 264 (75.2 %) had low FIB-4. LSM ≥ 8 kPa occurred in 17/264 (6.4 %) with low FIB-4 and 16/87 (18.4 %) with intermediate-to-high FIB-4 (OR 3.27, 95 % CI 1.57-6.81). Within the low-FIB-4 subgroup, diabetes was present in 70.6 % versus 20.0 %, and median waist-to-height ratio was 0.679 versus 0.620, in participants with versus without LSM ≥ 8 kPa. Adjusted ORs were 8.61 (95 % CI 2.59-28.64) for diabetes and 2.48 (1.23-4.99) per 0.1 higher waist-to-height ratio. CONCLUSIONS: Elevated liver stiffness was uncommon but not absent after a low FIB-4 result and was concentrated in participants with diabetes and central adiposity. Prospective validation should test whether these features improve selection for second-line liver assessment.