Autoimmune thyroid disease affects 1% of the general population, and autoimmune thyroid antibodies are noted in up to 15%.
We hypothesized systemic sclerosis (SSc) is associated with higher prevalence of antithyroglobulin (anti-Tg) and anti–thyroid peroxidase (anti-TPO) antibodies) to justify monitoring of thyroid function for earlier detection and treatment.
Waikato Hospital SSc clinic patients were prospectively tested for thyroid function tests and antithyroid antibodies (ATAs).
Of the 75 patients with SSc and 10 patients with SSc overlap syndrome (SOS) followed up in the SSc clinic, anti-Tg and anti-TPO were prospectively tested in 61 (70.6%) of the 85 patients. The cohort comprised 38 patients with limited cutaneous SSc (lcSSc), 15 with diffuse cutaneous SSc, and 8 with SOS.
Anti-Tg and anti-TPO antibodies were found in 34.2% in lcSSc patients and 33.3% in diffuse cutaneous SSc patients, whereas in SOS they were found in 25% (Tg) and in 12.5% (TPO) of patients.
At baseline, 10 patients (11.7%) had thyroid dysfunction: 8 (9.4%) with subclinical hypothyroidism and 1 each (1.2%) with subclinical hyperthyroidism and with clinical hyperthyroidism.
After 18 months, 1 woman with lcSSc, positive for both ATAs, developed clinical hypothyroidism.
There is a higher prevalence of ATAs in SSc and SOS compared with the general population. Screening these patients for ATAs is a reasonable measure.
From the *Rheumatology Department, Waikato Hospital; and
†Waikato Clinical School, University of Auckland, Hamilton, New Zealand; and
‡Rheumatology Department, Goulburn Valley Health, Shepperton, Victoria, Australia.
The authors declare no conflict of interest.
Correspondence: Kamal K. Solanki, FRACP, Rheumatology Department, Waikato Hospital, Pembroke St, Hamilton, New Zealand. E-mail: firstname.lastname@example.org.