Demographic and clinical features of autoimmune thyroid disorder in Japanese patients with systemic sclerosis

Autoimmune thyroid disorders (AITD) are characterized by the impairment of the thyroid gland as a result of systemic or organ-specific autoimmune disorders, and the presence of antithyroid autoantibodies, such as antithyroglobulin antibody (AbTg) and antithyroid peroxidase antibody (AbTPO). Several studies have reported the association of AITD with systemic sclerosis (SSc). However, none of those studies analyzed the association between AITD and skin sclerosis in SSc patients. The aim of this study was to examine the demographic and clinical features of SSc patients with AITD treated in our department. Of a total of 210 SSc patients, we identified 30 with AITD (14.3%), including 29 with Hashimoto's disease (13.8%) and one patient with Graves' disease (0.5%), indicating that hypothyroidism was more common among SSc patients with AITD. All patients with AITD were female, and anticentromere antibody positivity, the complication of Sjogren's syndrome, severe facial skin sclerosis and atrophy of the thyroid gland were significantly prevalent in SSc patients with AITD. SSc patients with such clinical features may be at high risk of AITD and require regular follow up of thyroid function including ultrasonography and the examination of serum hormone levels to start an early treatment.