Thyroid dysfunction and anti-thyroid antibodies in systemic sclerosis patients

Aim of the work

To assess the frequency of thyroid dysfunction and thyroid auto-antibodies in systemic sclerosis (SSc) patients.

Patients and methods

This study included thirty-three SSc patients and 30 matching controls. Thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), anti thyroglobulin (ATG) and anti thyroid peroxidase autoantibodies (ATPO) were measured in the sera of patients and controls.

Results

The mean age of the patients was 45.9 ± 13.05 years; 28 females and 5 males (F: M 5.6:1) and a disease duration of 4.58 ± 3.84 years. The FT3, FT4, TSH tended to be higher in patients (T3: 2.8 ± 0.66 pg/ml; T4: 1.5 ± 0.65 ng/ml; TSH: 1.9 ± 2.1 ul/ml) than in controls (p = 0.07, p = 0.21 and p = 0.24 respectively) while the ATG level in patients was 40 ± 21.3 IU/ml and ATPO 36.7 ± 88.2 IU/ml. Four patients had hypothyroidism (12 %); 3 (9 %) subclinical hypothyroidism (SCHT) and 1 (3 %) clinical hypothyroidism (CHT). ATG was positive in one patient and in 2 controls while ATPO was positive in two patients compared to one control. Both antibodies were positive in one patient. ATPO was associated with SCHT in one (3 %) and with overt hypothyroidism in another (3 %). The thyroid profile, ATG and ATPO were comparable between females and males (p = 0.34, p = 0.23, p = 0.96, p = 0.77 and p = 0.35 respectively) and all were similar between lcSSc and dcSSc except TSH (lower in dcSSc; p = 0.03). Muscle weakness was significantly higher among ATPO positive patients (p = 0.005) while thyroid dysfunction was significantly associated with arthralgia (p = 0.007).

Conclusion

Thyroid dysfunction mainly hypothyroidism is more frequent among SSc patients.