Background: Literature data regarding the prevalence of the syndromes of thyroid autoimmunity (AIT) in antiphospholipid syndrome (APS) are rather limited. However, quite frequently it is hypothesized on common pathophysiologic mechanisms underlining these disorders.
Objectives: The aim of this investigation was to evaluate the frequency of disorders of thyroid function and occurrence of anti-thyroid antibodies (ATAs) among patients with antiphospholipid syndrome (APS) included in the Serbian National APS Registry.
Methods: Started in January 2006, Serbian National APS Registry currently records information about 267 patients (206 females) in its database. These patients had a mean age of 44.89+12.95 years and mean disease duration of 4.41+4.07 years. Authors are planning to analyze serum levels of TSH, free thyroxine (fT4), anti-thyroglobulin antibody (TgAb), anti-thyroid peroxidase antibody (TPOAb) and thyroid receptor antibody (TRAb) in all of these patients. Now, we are presenting initial results obtained from 68 patients (comprising 25.46% of all patients included in Serbian National APS Registry) who undergone endocrinology screening during last year.
Results: Thyroid involvement was observed in 30.9% (21 patients, 20 females) of studied patients with APS. All of these patients were positive for at least one of the anti-thyroid antibodies, TgAb or TPOAb. On the contrary, no one of them was found positive for TRAb. We found no case of active hyperthyroidism in this sample, but according to previous medical data six of them had a history of treatment for hyperthyroidism. Hypothyroidism requiring substitution treatment was found in 14.8% (ten patients) of patients with APS. All of these patients were positive for at least one of the anti-thyroid antibodies.
Conclusion: Coexistence of the syndromes of thyroid autoimmunity and antiphospholipid syndrome in significant percent of patients is obvious. However, mutual genetic and/or pathophysiologic mechanisms connecting antiphospholipid syndrome and autoimmune thyroid diseases have yet to be proven.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.