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Published on: February 26, 2013
Increased risk of ischemic stroke and systemic embolism in hyperthyroidism-related atrial fibrillation: A nationwide
Kyu Kim1, Pil-Sung Yang2, Eunsun Jang1
1Division of Cardiology, Department of Internal Medicine, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
Insights
Patients with atrial fibrillation (AF) related to hyperthyroidism face increased risks of ischemic stroke and systemic embolism. Treating hyperthyroidism significantly lowers these risks, highlighting the importance of thyroid management in AF patients.
Area of Science:
- Cardiology
- Endocrinology
- Epidemiology
Background:
- Atrial fibrillation (AF) is a common arrhythmia.
- Hyperthyroidism is a known risk factor for cardiovascular events.
- The specific long-term risk of thromboembolic events in hyperthyroidism-related AF is not fully understood.
Purpose of the Study:
- To evaluate the long-term risk of ischemic stroke and systemic embolism in patients with hyperthyroidism-related atrial fibrillation.
- To compare these risks with non-hyperthyroidism-related (nonthyroidal) atrial fibrillation.
- To assess the impact of hyperthyroidism treatment on these risks.
Main Methods:
- Retrospective population-based cohort study using Korean National Health Insurance Service data (2005-2016).
- Included 615,724 oral anticoagulation-naïve patients with new-onset non-valvular AF.
- Propensity score matching was used to compare 20,773 hyperthyroidism-related AF patients with nonthyroidal AF patients.
Main Results:
- Hyperthyroidism-related AF patients had a significantly higher risk of ischemic stroke and systemic embolism (HR, 1.13; P < 0.001) compared to nonthyroidal AF patients.
- This increased risk was particularly pronounced within the first year of AF diagnosis (HR, 1.36; P < 0.001).
- Treatment for hyperthyroidism significantly reduced the risk of ischemic stroke and systemic embolism (HR, 0.64; P < 0.001).
Conclusions:
- Hyperthyroidism-related AF is associated with elevated risks of ischemic stroke and systemic embolism, similar to nonthyroidal AF, especially upon initial diagnosis.
- Effective management and treatment of hyperthyroidism are crucial for mitigating these thromboembolic risks in AF patients.
- These findings underscore the importance of integrated care for patients with both AF and thyroid dysfunction.
Background:
We aimed to evaluate the long-term risk of ischemic stroke/systemic embolism of hyperthyroidism-related AF.
Methods:
This retrospective population-based cohort study included records of 1,034,099 atrial fibrillation patients between 2005 and 2016 from the Korean National Health Insurance Service database. After exclusion, we identified 615,724 oral anticoagulation-naïve patients aged ≥18 years with new-onset non-valvular atrial fibrillation, of whom 20,773 had hyperthyroidism-related atrial fibrillation. After 3:1 propensity score matching, ischemic stroke and systemic embolism occurrences were compared between hyperthyroidism-related and non-hyperthyroidism-related ("nonthyroidal") atrial fibrillation patients.
Results:
After exclusion, we identified 615,724 oral anticoagulation-naïve AF patients of whom 20,773 had hyperthyroidism-related AF. Median follow-up duration was 5.9 years. Hyperthyroidism-related AF patients had significantly higher risks of ischemic stroke and systemic embolism than nonthyroidal AF patients (1.83 vs 1.62 per 100-person year, hazard ratio[HR], 1.13; 95% confidence interval[CI], 1.07 to 1.19; P < 0.001). This risk was 36% higher in hyperthyroidism-related than in nonthyroidal AF patients within 1 year of atrial fibrillation diagnosis (3.65 vs 2.67 per 100-person year, HR, 1.36; 95% CI, 1.24 - 1.50; P < 0.001). This difference was also observed in the CHA2DS2-VASc score subgroup analysis. The risk of ischemic stroke and systemic embolism significantly decreased in patients treated for hyperthyroidism (HR, 0.64; 95% CI, 0.58 to 0.70; P < 0.001).
Conclusions:
Hyperthyroidism-related AF patients have high risks of ischemic stroke and systemic embolism like nonthyroidal AF, especially when initially diagnosed. This risk is reduced by treating hyperthyroidism.
