Evaluation of the Clinical Outcomes of Apixaban Use in Patients with Atrial Fibrillation and Uncontrolled Hypothyroidism: A Real-world Evidence.

IntroductionAtrial fibrillation (AF) poses a substantial worldwide health concern, significantly increasing the risk of stroke and morbidity. Direct oral anticoagulants (DOACs) such as apixaban are recommended over vitamin K antagonists for the management of AF. However, the impact of thyroid abnormalities on DOACs, specifically apixaban in AF patients remains underexplored. Given the limited data, this study aims to evaluate the effectiveness and safety of apixaban in AF patients with uncontrolled hypothyroidism.MethodsThis study was a retrospective cohort analysis that categorized patients into two sub-cohorts according to their hypothyroidism status at the time they began apixaban treatment: a control group (without hypothyroidism) and an active group (with uncontrolled hypothyroidism). The primary outcome assessed was the rate of thrombosis events following the initiation of apixaban, while bleeding, stroke, and venous thromboembolism (VTE) events were considered as secondary outcomes. Logistic regression analysis was performed, with a p-value of less than .05 deemed statistically significant.ResultsAmong 292 patients included, 51 had uncontrolled hypothyroidism, and 241 were in the control group. Both groups had a median age of 70 years, with predominantly female patients. Any thrombosis events were higher in the uncontrolled hypothyroidism at crude analysis (17.6% vs 8.4%; p-value = .04); as well as higher odds at regression analysis [aOR: 2.40, 95%CI 0.99-5.83; p-value = .05]. In addition, stroke and major bleeding events were significantly higher in the uncontrolled hypothyroidism group (aOR: 4.26, 95%CI 1.51-12.00; p-value = .006 and aOR: 6.21, 95%CI 1.73-22.19; p-value = .005, respectively). The rate of VTE events and minor bleeding did not differ significantly between the two groups.ConclusionsThe use of apixaban in patients with AF and uncontrolled hypothyroidism was linked to higher rates of thrombosis and major bleeding compared to those without known hypothyroidism. These findings highlight the need for further research through larger prospective studies in this often-overlooked population.