Correlation between thyroid function, sensitivity to thyroid hormones and metabolic dysfunction-associated fatty liver disease in euthyroid subjects with newly diagnosed type 2 diabetes

Purpose To estimate the prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) and to evaluate the associations between thyroid parameters, MAFLD and liver fibrosis in euthyroid patients with newly diagnosed type 2 diabetes mellitus (T2DM). Methods Overall, 776 patients with newly diagnosed T2DM and 120 subjects without diabetes were included. All the participants were euthyroid, and were categorized as non-MAFLD and MAFLD. Demographic information, biochemical parameters, and serum thyroid hormones were collected. The thyroid hormone sensitivity indices were calculated. MAFLD was defined according to abdominal ultrasound and clinical manifestations. Noninvasive fibrosis indices were calculated to identify advanced liver fibrosis. Results The prevalence of MAFLD was significantly higher in patients with T2DM than in subjects without diabetes. Levels of free triiodothyronine (FT3) and FT3 to free thyroxine (FT4) ratio were significantly higher in subjects with MAFLD. In patients with T2DM, levels of thyroid stimulating hormone (TSH), Thyroid feedback quantile-based index (TFQI FT3 ) calculated using FT3 and TSH, thyrotroph T3 resistance index (TT3RI) and thyrotroph T4 resistance index (TT4RI) were significantly higher in subjects with MAFLD. The prevalence of MAFLD increased with the rise of FT3, FT3/FT4, TSH, and sensitivity to thyroid hormone indices (TFQI FT3 , TT3RI, and TT4RI). But significant correlations were not found between thyroid hormones, sensitivity to thyroid hormones and MAFLD, after adjustment for BMI and HOMA-IR. The incidence of advanced fibrosis tended to increase as the rise of TSH and sensitivity to thyroid hormone indices (TFQI FT3 , TT3RI, TT4RI, and TSHI). Conclusion MAFLD was prevalent in euthyroid patients with newly diagnosed T2DM. Higher normal FT3, TSH and impaired sensitivity to thyroid hormones are associated with increased incidence of MAFLD, being dependent on other metabolic factors.