SAT-431 Insulin Resistance, Lipid Profile and High-Sensitivity C-Reactive Protein in Patients with Autoimmune Thyroiditis

Abstract

Introduction: Thyroid function and autoimmunity has been associated with cardiovascular events in patients with autoimmune thyroiditis. Objectives: To evaluate the association between thyroid function, antithyroid antibodies levels, insulin resistance and markers of cardiovascular risk in patients with autoimmune thyroiditis. Methods: We evaluated 228 patients with autoimmune thyroiditis, 93.9 % female, with a mean age of 47.06 ± 15.35 years. We analyzed thyroid function, anti-thyroglobulin antibodies (anti-Tg), anti-thyroid peroxidase antibodies (anti-TPO), HOMA-IR, HOMA-B, QUICKI, HISI (Hepatic Insulin Sensitivity Index), WBISI (Whole-Body Insulin Sensitivity Index), the levels of lipid profile, high-sensitivity C-reactive protein (hs-CRP), homocysteine, folic acid, and vitamin B12. We defined 3 groups based on TSH levels: TSH between 0.35-2.49 µUI/ml, (n = 166), TSH between 2.50-4.94 µUI/ml, (n = 43) and TSH over 4.95 µUI/ml, (n = 19), and normal levels of free T4 and free T3. A 75-g OGTT was performed in the morning and blood samples were obtained every 30 min for 120 min for measurements of plasma glucose, insulin, and C-peptide. For the statistical analysis we used the Mann-Whitney test and Spearman correlations. Results are expressed as means ± SD or percentages. A two-tailed p<0.05 was considered statistically significant. Results: There were no significant differences regarding median age or median BMI between groups. We did not find any significant differences comparing group with TSH 0.35-2.49 and group with TSH 2.50-4.94, in all parameters evaluated. Group with TSH 2.50-4.94 had higher indexes of QUICKI (0.69 ± 0.39 vs 0.48 ± 0.13; p = 0.02) and HISI (79.83 ± 63.72 vs 41.73 ± 29.02; p = 0.01) than group with TSH over 4.95. The group with TSH over 4.95 demonstrated a higher index of HOMA-IR than group with TSH 2.50-4.94 (3.77 ± 2.93 vs 1.95 ± 1.24; p = 0.01). In the TSH 0.35-2.49 group we found significant correlations between TSH and HOMA-IR (r= 0.18; p = 0.01), total cholesterol and anti-TPO (r =0.23; p = 0.002), anti-Tg and HDL-cholesterol (r= -0.17; p=0.002), anti-Tg and triglycerides (r=0.34; p < 0.001), and anti-Tg and LDL-cholesterol (r=0.16; p=0.03). In the TSH 2.50-4.94 group we observed positive correlation between Apo A1 and HOMA-B (r=0.58; p<0.001), HOMA-IR and LDL-cholesterol (r=0.34; p=0.02) and WBISI and HDL-cholesterol (r=0.34; p=0.02). In the TSH over 4.95 group we observed a correlation between TSH and triglycerides (r=0.70; p<0.001) and between anti-Tg and hs-CRP (r=0.64; p=0.004). Conclusions: The association among TSH, lipid profile, insulin resistance, hs-CRP and antithyroid antibodies in patients with autoimmune thyroiditis may contribute to an increased cardiovascular risk, not only in patients with subclinical hypothyroidism but also in those classified as euthyroid.