Fatigue in Patients with Autoimmune Thyroid Diseases

Abstract

Fatigue is a common feature in a wide variety of chronic infl ammatory and autoimmune diseases, but fatigue in autoimmune thyroid disease (AITD) has not been investigated so far. Th e aim of this study was to examine fatigue in patients with AITD and to analyse the correlation between fatigue and the serum concentrations of thyroid antibodies, thyroid function and depression. Th is cross-sectional clinical study included 62 patients with increased concentrations of thyroperoxidase antibodies (TPOAbsThe concentration of TPOAbs was determined by a radioligand assay (TPO-Ab-CT, Cis-Biointernational, France) according to the manufacturer's instructions. The lower detection limit for this assay was 8 U/ml. The measured TPOAb concentrations were analysed towards the value of 130 U/ml, whereas autoantibody concentrations higher than 130 U/mL were considered "increased".The concentration of TgAb was determined by a competitive "one-step" radioimmunoassay (TgAb I step, CisBiointernational, France). The method was calibrated against the WHO First International Reference Preparation CRM 65/93 and had an analytical detection limit of 6.0 IU/ml. Autoantibody concentrations higher than 30 IU/mL were considered "increased".The concentration of free thyroxine (fT4) was determined by a radioimmunoassay (Cis-Biointernational, France). The detection limit for this assay was 0.5 pg/ml, and the reference range was 7-18 pg/ml.The concentration of thyrotropin (TSH) was determined by an immunoradiometric assay (IRMA TSH, Zemun, Serbia), with a detection limit of 0.056 mIU/L and reference range of 0.3-5.5 mIU/L.