Rheumatic Disease Autoantibodies in Patients with Autoimmune Thyroid Diseases

Area of Science:

• Rheumatology
• Endocrinology
• Immunology

Background:

• Autoimmune thyroid diseases (ATD), including Graves' disease (GD) and Hashimoto thyroiditis (HT), are sometimes associated with non-organ specific autoantibodies.
• Antinuclear antibodies (ANA) and rheumatoid factor (RF) are examples of such autoantibodies that may be present in ATD patients.

Purpose of the Study:

• To determine the prevalence of rheumatic autoantibodies in ATD patients without diagnosed rheumatic conditions.
• To explore the association between these autoantibodies and patient demographics/treatments.
• To monitor ATD patients with positive autoantibodies for the development of rheumatic disorders.

Main Methods:

• 154 ATD patients (70 HT, 84 GD) underwent testing for ANA, extractable nuclear antigen profile, and RF.
• Patient data on epidemiology and treatment were collected via chart review.
• Participants were followed for a mean of 5 years (2010-2015) to observe for rheumatic disease development.

Main Results:

• ANA was detected in 17.5% of patients; specific antibodies included anti-Ro/SS-A (2.5%), anti-RNP (2.5%), and anti-La/SS-B (1.9%). No anti-Sm antibodies were found.
• Rheumatoid factor (RF) was present in 7.7% of patients, more frequently in older individuals (p=0.007).
• A positive association was observed between RF and ANA (p=0.03; OR 3.89).

Conclusions:

• Rheumatic autoantibodies were identified in 17.5% of ATD patients without prior rheumatic diagnoses.
• No patients who tested positive for these autoantibodies developed clinical rheumatic diseases during the five-year follow-up period.