Coeliac disease is a risk factor for the development of seronegative arthritis in patients with autoimmune thyroid...

Hashimoto's thyroiditis is known to cluster with other systemic autoimmune disorders. Rheumatic manifestations, such as a seronegative non-erosive polyarthritis have been described. The aim of this study was to evaluate the characteristics and the prevalence of rheumatic features in thyroiditis patients, and to ascertain whether the association with systemic autoimmune disorders improved the arthritis manifestations.

In total, 180 thyroiditis patients were enrolled. Major clinical and demographic characteristics have been recorded. Patients underwent a rheumatological clinical assessment and extra-articular manifestations allowing for a differential diagnosis with systemic autoimmune diseases and spondyloarthropathy. Presence of systemic autoimmune diseases was recorded.

A total of 8.33% of thyroiditis patients shown a peripheral inflammatory arthritis (P = 0.002). Female gender (P = 0.042) and thyroid peroxidase (TPOAbs) positivity (P = 0.001) were more frequent. In total, 37 patients had systemic autoimmune diseases (P = 0.0003). A significant high prevalence of coeliac disease and Addison disease was found (P = 0.034 and P = 0.049, respectively). In patients with coeliac disease, the articular manifestations were more frequent (21.21%) (P = 0.001) and the risk to develop joint involvement was 2.96.

Although we found an articular involvement in about one-third of thyroiditis patients, the prevalence of inflammatory arthropathy was only 8.33%. The prevalence of other coexisting autoimmune disorders was 34.26% with a significant prevalence of coeliac disease (7.41%). Thyroiditis patients with coeliac disease have an articular involvement more frequently than those without. In these patients, we have found a high risk of developing arthritis than patients with only thyroiditis, suggesting cumulative autoimmune effects in the developing articular involvement.