Atrial fibrillation and associated cardiovascular disorders in adults with hyperthyroidism: a retrospective cohort study from two teaching hospitals

Abstract

Atrial fibrillation (AF) is a major cardiovascular complication of thyrotoxicosis but its burden and predictors are poorly described in sub-Saharan Africa. We assessed the prevalence, clinical course, and predictors of AF and related cardiovascular complications in adults with hyperthyroidism at two tertiary hospitals in Addis Ababa, Ethiopia. Retrospective cohort study of adults (≥ 18 years) with biochemically confirmed hyperthyroidism managed between April 2019 and September 2024. Clinical, ECG and echocardiographic data were abstracted from records; primary outcomes were AF at presentation and persistent AF on follow-up. Associations were examined with multivariable logistic regression. Of 174 patients (mean age 41.2 ± 11.6 years; 91.9% female), 43 (24.7%) had AF at presentation and 34 (19.5%) remained in persistent AF. Thromboembolic events (echocardiographic contrast n = 2; LV thrombus n = 1; ischemic stroke n = 1) occurred only in persistent AF. Independent predictors of AF included left atrial enlargement (LA ≥ 3.8 cm; AOR 8.6, 95% CI 1.9–38.5), NYHA class III–IV at presentation (AOR 8.9, 95% CI 2.5–33.0), diastolic dysfunction (AOR 5.4, 95% CI 1.4–21.5) and elevated baseline free T3 (AOR 12.5, 95% CI 3.1–50.2). Most patients received propylthiouracil (97.7%) and beta-blockers; anticoagulation was infrequently prescribed (n = 3). Biochemical normalization was slow, and AF was associated with delayed thyroid hormone normalization. In this Ethiopian tertiary-care cohort, AF was common and frequently persistent; elevated thyroid hormone levels and atrial structural changes were strong predictors. Early ECG and targeted echocardiography, prompt restoration of euthyroidism, and guideline-directed anticoagulation for high-risk patients are warranted to reduce thromboembolic and heart-failure complications.