Endocrine Abstracts

Introduction: Hypothyroidism is the most frequent thyroid disorder in patients with systemic lupus erythematosus (SLE) but the cause of this association is not well established. Moreover, no studies focused on the possible relationship between some specific immunologic patterns of SLE and the development of hypothyroidism have been reported.

Methods: In our study, we determined the immunological features and the thyroid status of 103 consecutive patients with SLE in a cross-sectional study. Complete immunological profile was done in all patients. Also, laboratory evaluation for free serum triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH), antithyroglobulin antibodies and thyroid peroxidase antibodies was performed.

Results: About 94% were females, mean age: 38.2±14.5 years and mean duration of SLE 8.8±6.2 years. Hypothyroidism was found in 17.5% (44.4% autoimmune in nature). No specific pattern of anti-DNA was more prevalent in patients with hypothyroidism. Hypothyroidism was significantly more frequent in patients with simultaneous positivity for autoantibodies Ro60, Ro52 and anti-La/SSB (25% vs 9,7%; P=0.027). Regardless of thyroid status, patients with more number of positive autoantibodies had higher TSH value but significant difference was not observed. Prevalence of autoimmune nature of hypothyroidism was higher in patients with two or more positive results for SLE-autoantibodies but the small number of patients in our cohort did not allow us to find significant difference (42.9 vs 14.3%; P=0.53).

Conclusions: Our data suggest that hypothyroidism is frequent in SLE and it could be influenced by immunological features. Therefore, we conclude that ordering thyroid test in SLE patients with more than one positive result for SLE autoantibodies is recommended. However, studies with a larger number of patients are needed to confirm this hypothesis.