Cardiovascular Risk Factors, Autoimmunity And Insulin Resistance In Graves' Disease

Introduction: Graves' disease is an autoimmune disease accounting for the majority of hyperthyroidism cases, with a multisystemic influence. Our aim was to assess the interrelationships between cardiovascular risk factors, autoimmunity and insulin resistance 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 (TV), BMI, glucose, HbA1c, HOMA-IR (homeostatic model assessment for insulin resistance), levels of total cholesterol, HDL, LDL-cholesterol, triglycerides, apolipoprotein B, apoA1, lipoprotein(a), CRP (C-reactive protein), folic acid, B12 vitamin in 85 patients with Graves' disease, defined by TSH<0.35 mu UI/mL, T3L>3.71 pg/mL and/ or T4L>1.48 ng/dL and TRAb>1.8 U/L. Patients were divided in subgroups according to performed treatment: we compared patients with definitive treatment [surgery (27.1%) versus iodine 131 (10.5%)] and patients treated with antithyroid drugs [ in remission ( 42.4%) versus in treatment with anti-thyroid drugs (20%)]; and according to autoimmunity profile [positive TRAb (9.4%) or negative TRAb (81.2%)]. Then we divided patients in active disease [positive TRAb and/or in treatment with anti-thyroid drugs (27,1%)] and non-active disease [negative TRAb and not actually in treatment with anti-thyroid drugs, and may be previously treated with surgery or Iodo 131 (64,7%)].Pearson correlation, t-test and Mann-Whitney test were performed for statistical analysis.Results: The mean age of the population was 52.9 +/- 13.0 years with 89.4% female patients. Regarding TRAbs subgroups there was a positive correlation between TSH and PCR (r=0.8,p=0.010) in positive TRAb subgroup. Comparing with the remission subgroup, significantly higher TV (20.7 +/- 9.9 vs 15.4 +/- 7.7 mL, p=0.048) and thyroglobulin [45.9 (18.4-59.4) vs 7.5 (1.3-16.2) ng/mL, p=0.001] and significantly lower TSH [0.7 (0.4-1.4) vs 2.7 (1.1-2.9) mu UI/mL, p=0.002] were found in patients currently treated with antithyroid drugs. There was a positive correlation between TV and apoB (r=0.9,p=0.034) and between TSH and PCR (r=0.6,p=0.034) in currently treated subgroup.TV and HbA1c (r=0.4,p=0.023) were positively correlated in remission subgroup.Conclusion: The interrelationships found between autoimmunity, insulin resistance, inflammation and lipid profile may contribute to the cardiovascular risk in Graves' disease.