Autoimmune Thyroiditis and Rheumatoid Arthritis

Is There Really an Association?

Abstract

Previous studies suggest an association between autoimmune thyroid disease (AITD), an organ-specific autoimmune disease, and rheumatoid arthritis (RA), a systemic autoimmune disorder. However, this association is controversial because of the variability in the prevalence of AITD in RA patients. The aim of this study is to determine whether there is relationship between AITD and RA. This case-control study included 189 patients who were consecutively seen in the Rheumatology Clinics of HC-UFU/MG: 72 with RA (ARA criteria, 1987) and 117 with nonautoimmune rheumatic diseases. Blood samples were collected from all subjects for TSH, FT4, anti-TPO, and anti-Tg measurement; RA patients were also tested for rheumatoid factor and antinuclear antibodies and the Disease Activity Score using 28 joint counts was assessed to measure the disease activity. Thyroid dysfunction was found in 11, and thyroid autoantibodies in 15 RA patients, compared with 18 and 13 of the control group, respectively. There was no correlation between thyroid disease and rheumatoid factor, antinuclear antibodies, disease modifying drugs use, corticosteroid use, or RA disease activity. In conclusion, no association could be demonstrated between thyroid disease and RA. This suggests that, at least in some populations, this association does not occur, or it is not strong enough—from the epidemiologic point of view—to justify the routine thyroid antibodies and thyrotropin tests in all RA patients.