Endocrine Abstracts

Background: The association between spondylarthritis and thyroid diseases is unclear. Few studies have examined this association and results remain unknown. We aimed to assess the frequency of thyroid disorders among patients with spondylarthritis.

Methods: We performed a cross-sectional study including 50 patients with spondyloarthritis (SA) diagnosed according to ASAS criteria. The disease activity was assessed using ASDAS Free Thyroxine(FT4) and thyroid stimulating-hormone (TSH) were measured for each patient.

Results: The mean average was 45.75 ± 13.18 years. The sex-ratio was 3. Clinical phenotypes of SA were: ankylosing spondylarthritis (60%), psoriaticarthritis (22.5%), arthritis associated with inflammatory bowel disease (12.5%). The mean duration of the disease was 91.6 ± 61.17 months. The mean C-reactive protein and erythrocyte sedimentation rate were 32.21 ± 43.09 mg/l and 34.36 ± 24.9 mmH1 respectively. The mean ASDAS-CRP and BASMI were 3.83 ± 2.33 and 2.11 ± 2.23. The mean FT4 and TSH levels were 12.23 and 1.89 respectively. There is no Correlation between ASDAS, BASMI, inflammatory markers, and Thyroid hormone (FT4 and TSH). Disorder of at least one thyroid function test (FT4 or TSH) was noted in 27.5% of cases (n = 11). Among these patients: 10% of patients (n = 4) had a central hypothyroidism(low FT4 level and normal TSH level), 2.5% of patients (n = 1) had a subclinical hyperthyroidism (n ormal FT4 level and low TSH level), and 2.5% of patients (n = 1) had acquired hyperthyroidism (high FT4 level and low TSH level). A normal TSH associated with high FT4 was found in 12.5% of (n = 5). This finding may correspond to thyroid hormone resistance, an artifact or a thyrotropic microadenoma.

Conclusion: Our study showed that thyroid disorder is not uncommon in patients with SA. The main disorder observed in our study is a high free T4 associated with normal TSH level. Our study suggests that the screening of thyroid disorder is mandatory in patients with SA.

Reference

1. Emmungil H, Erdogan M, Kalfa M, Karabulut G, Kocanaogulları H, Inal V, et al. Autoimmune thyroid disease in ankylosing spondylitis. Clin Rheumatol. juill 2014 33(7) 955–961.