Abstract 16190: Subclinical Hyperthyroidism and Risk of Atrial Fibrillation: A Systematic Review and Meta-analysis
Introduction: Overt hyperthyroidism is a well-known risk factor for development of atrial fibrillation (AF). On the other hand, studies assessing risk of AF in patients with subclinical hyperthyroidism (SCH), have reported conflicting results on the directionality and the strength of this association. We therefore systematically reviewed published literature and performed a quantitative analysis to assess the risk of AF in these patients.
Methods: A comprehensive search of articles assessing the risk of AF in patients with SCH was done in PUBMED and COCHRANE databases through May 2015. SCH was defined as decreased Thyroid stimulating hormone (TSH) level accompanied by normal concentrations of serum thyroid hormone in asymptomatic patients. After screening abstracts, full texts of potentially relevant studies were reviewed independently by two authors. Data was extracted on standardized forms. Meta-analysis was performed using random effects model (DerSimonian Laird). The main measure of association was relative risk with 95% confidence intervals.
Results: A total of 7119 patients with SCH and 588,839 controls across 4 studies were included in the analysis based on predefined inclusion and exclusion criteria. The relative risk for AF was significantly increased in patients with SCH compared to controls [relative risk: 2.48 (CI: 1.50-4.09; p< 0.001)] during a mean follow up of 5.5 years. There was no significant heterogeneity or publication bias. Sensitivity analysis by exclusion of individual studies had no impact on the summary effect estimate. One study reviewed but not included in the quantitative analysis demonstrated increased risk of AF in patients with low normal TSH compared to mid normal range.
Conclusion: This analysis demonstrates that the risk of AF is >2 fold higher in the presence of SCH. It remains to be seen whether treatment of these patients before development of overt hyperthyroidism decreases the risk of AF.
Author Disclosures: V. Veerappan Kandasamy: None. A. Saurav: None. A. Kaja: None. V. Alla: None.
- © 2015 by American Heart Association, Inc.