Prevalence and impact of thyroid dysfunction in patients with rheumatoid arthritis

Thyroid disorders are common in patients with autoimmune diseases such as rheumatoid arthritis (RA). Both conditions present significant public health concerns due to their impact on quality of life and increased mortality. The aim of this study was to assess the prevalence of thyroid abnormalities in and investigate their influence on rheumatoid arthritis characteristics. This was a case-control study involving adult female patients with RA and age-matched healthy controls. RA disease activity was evaluated using the Disease Activity Score (DAS28), and functional impact was assessed using the Health Assessment Questionnaire (HAQ). Serum thyroid function tests were performed, including thyroid-stimulating hormone (TSH), free thyroxine (FT4), and antithyroid antibodies (TAAs), including anti-thyroglobulin antibodies (TgAb), anti-thyroperoxidase antibodies (TPOAb), and TSH receptor antibodies (TRAb). The study included 58 female RA patients, with a mean age of 52 ± 14.2 years. The median disease duration was 10.41 years. The median DAS28-CRP was 4.03, and the median HAQ was 1.34. The median FT4 and TSH levels were 15.01 [13.48;16.71] and 1.42 [0.91;2.26], respectively. Thyroid dysfunction was identified in 19% of the participants, with hypothyroidism being the most common disorder (17%). Hyperthyroidism was observed in 2% of patients. Antithyroid antibodies were positive in 15.5% (n = 9) of participants, with TPOAb present in 6 patients (10.3%), TgAb in 3 patients (5.2%), and TRAb in 2 patients (3.4%). No statistically significant association was found between thyroid status and RA disease activity, functional impact, or serological status. Despite the lack of correlation, the high prevalence of thyroid dysfunction underscores the importance of regular thyroid screening to optimize management and prognosis in RA patients.