THE RISK for autoimmune thyroid disease decreases following rheumatoid arthritis (RA) diagnosis, according to new research conducted at Karolinska Institutet, Stockholm, Sweden. This decrease is especially pronounced in patients with RA treated with biologic disease-modifying antirheumatic drugs (bDMARD).
Lead author Kristin Waldenlind, and colleagues, collected data from 13,731 patients with new-onset RA from the Swedish Rheumatology Quality Register (SQR), from 2006–2018 (64.7% females; mean age: 59.4 years). Adults with RA were matched with 63,201 individuals from the general population (control group).
Over a median follow-up of 6.3 years for those with RA, and 6.4 years for the control group, 2.3% of the RA group and 2.9% of adults without RA developed autoimmune thyroid disease. Adults diagnosed with RA had a 46% lower risk of developing autoimmune thyroid disease than those without RA (adjusted hazard ratio [HR]: 0.81; 95% confidence interval [CI]: 0.72–0.91). Furthermore, the risk for developing autoimmune thyroid disease was more greatly reduced in adults receiving bDMARDs (HR: 0.54; 95% CI: 0.39–0.76), compared with the control group. Patients with RA who initiated bDMARDs also had a lower risk for autoimmune thyroid disease than those with RA who did not use bDMARDs (HR: 0.65; 95% CI: 0.45–0.93).
In a subgroup analysis examining only patients with RA, those <40 years who were receiving antirheumatic drugs had a lower risk for autoimmune thyroid disease than those who did not use an antirheumatic drug (HR: 0.46; 95% CI: 0.21–0.98). The risk for autoimmune thyroid disease was lower for adults who received concomitant methotrexate, compared with those not receiving bDMARDs (HR: 0.64; 95% CI: 0.42–0.96). TNF inhibitors were associated with the most pronounced decrease in risk (HR: 0.67; 95% CI: 0.47–0.96). No decreased risk for autoimmune thyroid disease was observed for rituximab or other bDMARDs.
These findings support the hypothesis that bDMARDs might have a preventive effect on autoimmune thyroid disease. Waldenlind concluded: “If further studies support these findings, it opens up to more direct study in clinical trials, if disease-modifying antirheumatic drugs currently used for rheumatoid arthritis could also be used for the early treatment of autoimmune thyroid disease.”
