Endocrine Abstracts

Introduction: Graves’ disease is an autoimmune disease accounting for the majority of hyperthyroidism cases.

Aim: We aimed to assess the interrelationships between cardiovascular risk factors, autoimmunity, insulin resistance and treatment in Graves’ disease.

Material and methods: We measured free T3 (FT3), free T4 (FT4), TSH, thyrotropin receptor antibodies (TRAb), anti-thyroglobulin and anti-TPO antibodies, thyroid volume (each lobe’ volumes sum, given by the formula 0.479 × depth × wide × length), BMI, glucose, HbA1c, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), levels of total cholesterol (TC), HDL, LDL-cholesterol, triglycerides (TG), apolipoprotein B (ApoB), apoA1, lipoprotein(a) (Lp[a]), homocysteine, CRP (C-reactive protein), folic acid, B12 Vitamin in 85 patients with Graves’ disease (89.4% female, 52.8±13.4 years). Patients were divided in subgroups according to autoimmunity profile (positive TRAb (9.4%) or negative TRAb (81.2%)] and treatment [previously treated (80%) or in treatment with anti-thyroid drugs (20%)). Then, we divided the previously treated subgroup according to performed treatment [thyroidectomy (33.8%), I¹³¹ (13.2%) or anti-thyroid drugs (53%)]. Pearson correlation, t-test and Mann-Whitney test were performed for statistical analysis.

Results: Regarding TRAbs subgroups there was a positive correlation between Lp(a) and thyroid volume (r=0.4726, P=0.0228) in positive TRAb subgroup. A negative correlation between thyroid volume and FT3 (r=−0.4710, P=0.0065) was found in negative TRAb subgroup. Comparing with the previously treated subgroup, significantly higher thyroid volume (20.685±9.86 ml vs 15.43±1.398 ml, P=0.0480) and thyroglobulin (74.22±35.29 ng/ml vs 16.47±6.47 ng/ml, P=0.0315) and significantly lower TSH (0.85±0.15 UI/ml, vs 2.3±0.41 UI/ml, P=0.0139) were found in patients currently treated with antithyroid drugs. There was a positive correlation between HbA1c and thyroid volume (r=0.4290, P=0.0255), and between CRP and TC (r=0.4362, P=0.0375) in the previously treated subgroup. Regarding evaluation by performed treatment, significantly lower FT3 (2.395±0.37 pg/ml, IC95 (2.231–2.560), P=0.0319 vs 3.02±0.177 pg/ml, IC95 (2.67-3.38), P=0.032) was found in patients who performed thyroidectomy. In the thyroidectomy subgroup there was a positive correlation between FT3 and HOMA-IR (r=0.5734, P=0.0103). In patients without previous surgery or I¹³¹ treatment there was a positive correlation between age and thyroid volume (r=0.2972, P=0.0425), homocysteine and TRAb (r=0.7911, P=0.0341) and a negative correlation between thyroid volume and TRAb (r=−0.5275, P=0.0358).

Conclusion: In patients with Graves’ disease, we found significant interrelationships between thyroid volume and function, autoimmunity, lipid and glycaemic profiles. These associations may contribute to the cardiovascular risk in Graves’ disease.