Non-specific rheumatic manifestations in patients with Hashimoto's thyroiditis: a pilot cross-sectional study

Hashimoto's thyroiditis (HT) is often associated with rheumatic disorders (arthritis, etc.), but many HT patients report non-specific rheumatic signs and symptoms in the absence of clinically evident rheumatic diseases. Aim of this study was to evaluate the prevalence of non-specific rheumatic manifestations (RMs) in HT subjects without classified autoimmune comorbidities.

500 HT patients (467 F, 33 M; median age 41 years, range 14-69) and 310 age- and sex-matched controls, consecutively referred to the Endocrine Unit of Messina University Hospital, were evaluated for non-specific RMs. None took L-thyroxine.

autoimmune comorbidities, infectious, and/or inflammatory diseases, history of neoplasia, BMI > 30 kg/m².

In our HT cohort, 100 patients (20%) complained of one or more RMs, vs 21 controls (6.8%; P < 0.001). There were minimal differences between the manifestations recorded in the two groups, the most common being polyarthralgias and myalgias/fibromyalgia, but non-specific RMs occurred threefold more in HT patients. Comparing HT patients with RMs (96 F and 4 M) with those affected by HT alone, female sex was prevalent (F:M ratio 24:1 vs 5:1) with higher age at diagnosis (median 43 vs 37 years; P < 0.001). HT patients with RMs (62%) were mostly euthyroid (median TSH 2.0 µIU/L) and only 7% overtly hypothyroid, discouraging a possible causal relationship between thyroid dysfunction per se and RMs.

A significant percentage of HT patients complains of non-specific rheumatic signs and symptoms, in the absence of other diagnosed systemic comorbidities and regardless of thyroid functional status, deserving careful evaluation and prolonged follow-up.