Disease-Modifying Antirheumatic Drugs Linked to Decreased Risk for Autoimmune Thyroid Disease

Findings from a recent study published in Journal of Internal Medicine suggest that the risk of developing autoimmune thyroid disease (AITD) for patients with rheumatoid arthritis (RA) can decrease following treatment with biologic disease-modifying antirheumatic drugs (bDMARDs).

Previous research has indicated that AITD is one of the more prevalent comorbidities affecting patients with RA. Furthermore, AITD is cited as the most prevalent autoimmune disease on a global scale, affecting up to 5% of the general population. The relationship between RA and AITD stems from an intricate interaction between genetic and environmental components, including genes associated with T-cell response, such as protein tyrosine phosphatase nonreceptor type 22 and cytotoxic T-lymphocyte–associated antigen 4.

Autoimmune Thyroid Disease Model | image credit: Jo Panuwat D - stock.adobe.com

At present, the standard treatment paradigm for patients with RA is DMARDs or bDMARDs. Despite similarities in their genetic backgrounds, the typical treatment for AITD involves hormone replacement therapy and foregoes DMARD intervention. As the authors of the present study note, previous study findings indicate the potential benefits of DMARD treatment are postponing the onset of AITD or preventing it altogether. However, evidence backing up this association is lacking. To address this gap in knowledge, the researchers conducted a study to investigate the risk of AITD in patients with RA compared with the general population and whether DMARDs can be linked to these incidence rates.

Between January 1, 2006, and December 31, 2018, data from 13,731 patients with RA were gathered through the Swedish Rheumatology Quality Register. Each patient with RA was age and sex matched with up to 5 individuals from the general population (controls, n = 63,201). All individuals were followed until onset of AITD, death, the end of the study period, or emigration.

By the end of patient follow-ups, 321 patients with RA (2.3%) and 1838 controls (2.9%) had developed AITD (3.7 vs 4.6 events, respectively, per 1000 person-years). These rates of AITD incidence and risk in patients with RA was statistically significantly lower than the general population (HR, 0.81; 95% CI, 0.72-0.91). Furthermore, the authors observed lower incidences of AITD occurring in individuals enduring RA for a longer duration (10-14 years following RA diagnosis: 2.9 vs 4.5 events of AITD per 1000 person-years; HR, 0.64; 95% CI, 0.37-1.09).

Compared with the general population, patients with RA who were treated with bDMARDs exhibited significantly lower rates of AITD incidence (HR, 0.54; 95% CI, 0.39-0.76). This trend continued within the RA cohort as well with bDMARD-treated patients compared with patients with RA who remained naïve to bDMARDs (HR, 0.65; 95% CI, 0.45-0.93). When patients with RA were subgrouped according to bDMARD use, the authors observed tumor necrosis factor inhibitors were correlated with the most substantial decrease in AITD incidence (HR, 0.97; 95% CI, 0.47-0.96).

The researchers’ findings validated past studies that suggested AITD prevalence decreases after a diagnosis of RA. Additionally, treatment approaches using bDMARDs were associated with further decreases in AITD development, suggesting that DMARDs have a potentially protective and preventive impact on AITD.

Reference

Waldenlind K, Delcoigne B, Saevarsdottir S, Askling J. Disease-modifying antirheumatic drugs and risk of thyroxine-treated autoimmune thyroid disease in patients with rheumatoid arthritis. Intern Med. Published online November 22, 2023. doi:10.1111/joim.13743