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 re...