Fatty liver index is an independent risk factor for all-cause mortality and major cardiovascular events in type 1 diabetes: an 11-year observational study

Background: Non-alcoholic fatty liver disease (NAFLD), identified by the Fatty Liver Index (FLI), is associated with increased mortality and cardiovascular (CV) outcomes. Whether this also applies to type 1 diabetes (T1D) has not been yet reported. Methods: We prospectively observed 774 subjects with type 1 diabetes (males 52%, 30.3 ± 11.1 years old, diabetes duration (DD) 18.5 ± 11.6 years, HbA1c 7.8 ± 1.2%) to assess the associations between FLI (based on BMI, waist circumference, gamma-glutamyl transferase and triglycerides) and all-cause death and first CV events. Results: Over a median 11-year follow-up, 57 subjects died (7.4%) and 49 CV events (6.7%) occurred among 736 individuals with retrievable incidence data. At baseline, FLI was < 30 in 515 subjects (66.5%), 30–59 in 169 (21.8%), and ≥ 60 in 90 (11.6%). Mortality increased steeply with FLI: 3.9, 10.1, 22.2% (p < 0.0001). In unadjusted Cox analysis, compared to FLI < 30, risk of death increased in FLI 30–59 (HR 2.85, 95% CI 1.49–5.45, p = 0.002) and FLI ≥ 60 (6.07, 3.27–11.29, p < 0.0001). Adjusting for Steno Type 1 Risk Engine (ST1-RE; based on age, sex, DD, systolic BP, LDL cholesterol, HbA1c, albuminuria, eGFR, smoking and exercise), HR was 1.52 (0.78–2.97) for FLI 30–59 and 3.04 (1.59–5.82, p = 0.001) for FLI ≥ 60. Inclusion of prior CV events slightly modified HRs. FLI impact was confirmed upon adjustment for EURODIAB Risk Engine (EURO-RE; based on age, HbA1c, waist-to-hip ratio, albuminuria and HDL cholesterol): FLI 30–59: HR 1.24, 0.62–2.48; FLI ≥ 60: 2.54, 1.30–4.95, p = 0.007), even after inclusion of prior CVD. CV events incidence increased with FLI: 3.5, 10.5, 17.2% (p < 0.0001). In unadjusted Cox, HR was 3.24 (1.65–6.34, p = 0.001) for FLI 30–59 and 5.41 (2.70–10.83, p < 0.0001) for FLI ≥ 60. After adjustment for ST1-RE or EURO-RE, FLI ≥ 60 remained statistically associated with risk of incident CV events, with trivial modification with prior CVD inclusion. Conclusions: This observational prospective study shows that FLI is associated with higher all-cause mortality and increased risk of incident CV events in type 1 diabetes.