Patients with rheumatoid arthritis (RA) are at increased risk of developing thyroid dysfunction, particularly hypothyroidism, according to a study published in Frontiers in Endocrinology.1 The researchers urge biochemical examination of thyroid function in RA patients and state that larger prospective studies are needed to explore causal relationships between thyroid dysfunction and RA. The impact of thyroid dysfunction on disease activity, drug safety, and drug efficacy should also be examined.
“Most thyroid disease and rheumatoid arthritis are chronic diseases and unfortunately the early signs of thyroid dysfunction are non-specific and are often overshadowed by clinical manifestations of other diseases in the absence of evidence. biochemical parameters of thyroid function,” the researchers explained. “Thyroid dysfunction can be detrimental to health and, if left undiagnosed or untreated, can have serious adverse consequences and, in rare cases, can be fatal.”
A systemic review and meta-analysis used online literature databases, including PubMed, the Cochrane Library, Embase, and Scopus from inception to March 25, 2022, to explore the link between RA and thyroid dysfunction. Eligible studies provided data on one or more cases of thyroid dysfunction in RA patients and controls. The investigators evaluated pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for thyroid dysfunction in patients with RA and patients without RA.
In total, 29 studies, including 35,708 RA patients, met the inclusion criteria. A meta-analysis reported that RA patients were at increased risk of developing thyroid dysfunction compared with non-RA patients, particularly with regard to hypothyroidism (OR 2.25, 95% CI 1.78–2.84) and hypothyroidism subclinical (OR 2.18, 95% CI 1.32–3.61). The risk of developing hyperthyroidism in RA was also higher compared to control groups (OR 1.65, 95% CI 1.24–2.19) and RA patients had more than double the risk of developing subclinical hyperthyroidism in comparison with controls (OR 2.13, 95% CI 1.25–3.63). Further subgroup analysis indicated that study type and control group sample source were the source of heterogeneity.
The study was limited by the uneven quality of the 29 included studies, with 13.79% of abstracts classified as low quality. Another limitation was that all the studies were observational in nature, which, among other issues, made it difficult to establish a causal relationship between the diagnosis of RA and thyroid dysfunction. Clinical criteria for evaluating the relationship between RA and thyroid dysfunction were inconsistent and need to be addressed in future studies. Finally, factors such as gender, age, and disease course were not analyzed due to insufficient data.
“Our findings suggest that rheumatologists should assess thyroid function in RA patients and refer them to endocrinologists to determine effective strategies to prevent and treat thyroid dysfunction,” the researchers concluded. “In addition, since RA may share a common pathogenesis with most autoimmune thyroid diseases (AITDs) that cause thyroid dysfunction, there may also be corresponding treatment options. More potential mechanisms and treatment options should be explored in future studies.”
Liu YJ, Miao HB, Lin S, Chen Z. Association between rheumatoid arthritis and thyroid dysfunction: a meta-analysis and systematic review. Front Endocrinol (Lausanne). 2022;13:1015516. Published October 13, 2022. doi:10.3389/fendo.2022.1015516