Association Between Autoimmune Thyroiditis and Cervical Artery Dissection: A Retrospective Cohort Study

ABSTRACT Background and Aims Limited evidence suggests autoimmune thyroiditis (AT) could represent a risk factor for cervical artery dissection (CeAD). We tested the hypothesis of a positive association between AT and CeAD within 3 years following diagnosis compared to matched euthyroid controls. Methods We searched a de‐identified United States' data resource (TriNetX LLC) for adults age ≥ 18 with newly‐diagnosed AT, and euthyroid controls, from 2014 to 2024. Propensity matching controlled for variables associated with CeAD. Our primary outcome was the risk ratio (RR) for CeAD within 3 years' follow‐up. Secondary outcomes explored the cumulative incidence of CeAD and RRs for vertebral and carotid artery dissection and stroke. Results After matching, there were 143,831 patients per cohort (80% female). Comparing the AT cohort to matched euthyroid controls, the incidence and risk of CeAD was significantly greater [95% CI] (0.040% vs. 0.025%; RR = 1.58 [1.04, 2.40]; p = 0.029). Secondary outcomes included a non‐significant increase in incidence and risk of vertebral artery dissection (0.022% vs. 0.017%; RR = 1.28 [0.76, 2.16]; p = 0.354), and significant increase in incidence and risk of carotid artery dissection (0.019% vs. 0.008%; RR = 2.33 [1.19, 4.59]; p = 0.011) and stroke (2.1% vs. 1.3%; RR = 1.67 [1.58, 1.77]; p < 0.001). Cumulative incidence of CeAD in patients with AT highlighted a time‐dependent increase relative to euthyroid controls. Conclusion The present findings suggest that AT is a risk factor for CeAD. Additional research is needed to corroborate these findings and clarify factors that may mediate the AT‐CeAD association, such as medications, thyroid hormones, and antibody levels.