Thyroid dysfunction in patients undergoing long-term amiodarone therapy

Abstract: Amiodarone, a widely prescribed antiarrhythmic drug, is associated with significant thyroid dysfunction, including both hypothyroidism and hyperthyroidism. This systematic review and meta analysis aim to synthesize the available evidence on the prevalence, types, and management of amiodarone induced thyroid dysfunction (AITD) in patients on long term therapy. We conducted a systematic review and meta analysis of studies that examined thyroid dysfunction in patients receiving long term amiodarone therapy. A comprehensive search of PubMed, Google Scholar, and the Cochrane Library was performed, identifying studies published between 1990 and 2024. Eligible studies included prospective or retrospective cohort studies and randomized controlled trials (RCTs) reporting on the incidence of hypothyroidism, hyperthyroidism, and management strategies in this population. Twenty three studies, with a combined population of 12,000 patients, were included in the final analysis. The pooled incidence of hypothyroidism was 14.3% (95% confidence interval CI: 12.1%–16.9%, P < 0.001) and hyperthyroidism was 6.7% (95%CI: 5.1%–8.4%, P < 0.001). Geographical variation in incidence was noted, with higher rates of hyperthyroidism in iodine deficient regions. Amiodarone induced hypothyroidism was generally well managed with levothyroxine without discontinuing amiodarone. Amiodarone induced hyperthyroidism required either antithyroid drugs (for Type 1) or corticosteroids (for Type 2). Thyroid dysfunction, especially hypothyroidism, is common in patients receiving long term amiodarone therapy. Regular thyroid function monitoring is essential to manage this condition effectively. Further studies are needed to improve the management of amiodarone induced hyperthyroidism and optimize long term outcomes for these patients.