Endocrine Abstracts

Introduction: Nonalcoholic fatty liver disease (NAFLD) affects ±55% of subjects with type 2 diabetes and contributes to cardiovascular mortality. NAFLD data in type 1 diabetes (T1DM) are scarce. Biopsy is the diagnostic reference but is not suited for routine screening. Ultrasound (US) is validated to diagnose steatosis as first-line imaging but is restricted to trained operators. The Fatty Liver Index (FLI) is a score to predict fatty liver based on triglycerides, Body Mass Index (BMI), gamma-glutamyl-transpeptidase (GGT) and waist circumference (WC), and stratifies risk groups in primary work-up. FLI <30 is considered to rule out steatosis, FLI ≥60 to rule in steatosis and trigger referral. We investigated the reliability of FLI to predict steatosis using ultrasound as the reference method in T1DM.

Methods: We consecutively recruited 331 T1DM patients who underwent anthropometry, US and lab-tests. We used the area under the receiver operating characteristic curve (AUROC) and Youden’s Index to determine diagnostic accuracy.

Results: Prevalence of steatosis was 22% (74/331) based on US. WC (89 ± 13 vs 103 ± 14 cm, P ≤ 0.001), BMI (25. 3 ± 4.1 vs 30.0 ± 4.9 kg/m², P ≤ 0.001), GGT (33 ± 2 vs 47 ± 5 mU/l, P = 0.007), HDL (64 ± 16 vs 58 ± 18 mg/dl, P = 0.005) and triglycerides (80 ± 40 vs 113 ± 84 mg/dl, P ≤ 0.001) differed significantly between the steatosis and non-steatosis group. Age, gender and ALT did not differ. The AUROC of the FLI for diagnosis of steatosis was 0.78 (95% CI : 0.71–0.84). Optimal cut-off according to Youden’s Index was ≥30 (sensitivity 0.84, specificity 0.63, PPV 0.82, NPV 0.92). Thirteen subjects with steatosis on US had a FLI <30 (13/175:7.4%). We further assessed the predefined threshold of ≥60 (sensitivity 0.55, specificity 0.84, PPV 0.50 and NPV 0.87). Thirty-three out of 74 patients with steatosis had a FLI <60, so 45% of cases would not be diagnosed. Comparison of groups with FLI <30 and FLI 30–59 showed significant differences in systolic blood pressure (133 ± 17 vs 140 ± 20 mmHg, P = 0.004), creatinine (0.8 ± 0.2 vs 0.9 ± 0.6 mg/dl, P = 0.007) and HDL (67 ± 17 vs 57 ± 16 mg/dl, P < 0.001), indicating a higher metabolic risk profile in the latter.

Conclusion: Diagnostic accuracy of FLI for diagnosis of steatosis is moderate in T1DM patients with optimal cutoff ≥30. The FLI cutoff ≥60 would miss the diagnosis of steatosis in 45% of cases, whereas the cutoff ≥30 would miss only 7.4%. The subjects with a FLI score 30–59 had a more severe risk profile compared to subjects with FLI <30. Therefore, we propose the cutoff ≥30 in primary decision making based on FLI to diagnose NAFLD in T1DM patients.