Prevalence of Amiodarone Induced Hypothyroidism and Hyperthyroidism in Patients with Heart Diseases: A Systematic Review and Meta-Analysis

Background: Due to the importance of amiodarone-induced hyperthyroidism in patients with heart failure, the purpose of the present systematic review and meta-analysis was to determine the prevalence of thyroid dysfunction (hypothyroidism and hyperthyroidism) in patients with heart disease who received amiodarone. Methods: Electronic databases including Scopus, PubMed, Web of science, and Science Direct were searched by two investigators. To assess the heterogeneity between the included studies, the chi-square χ2 test (α=0.05) and I2 index were used. Additionally, a random-effects model with 95% CI was used to estimate the pooled prevalence of thyroid dysfunction due to heterogeneity of the studies. To identify the cause of heterogeneity, a meta-regression analysis was employed. All analyses were performed using Stata ver13 (Stata Corporation, College Station, TX, USA). Results: The pooled prevalence of hypothyroidism was 23.43% (95% CI: 11.54-35.33) and hyperthyroidism was 11.61% (95% CI: 7.20-16.02). There was no significant association between the prevalence of hypothyroidism and the year of the study (P=0.152), sample size (P=0.805), and mean age of subjects in the sample groups (P=0.623). However, there was a significant association between the prevalence of hyperthyroidism and the year of the study (p=0.037), but no statistically significant association between either the prevalence of hyperthyroidism and sample size (P=0.425), or the prevalence of hyperthyroidism and the mean age of subjects in the sample groups (P=0.447). Conclusion: The prevalence of thyroid dysfunction in patients with cardiac arrhythmias receiving amiodarone was considerable. Extreme care should be exercised to improve monitoring of any thyroid abnormalities that may arise in patients receiving amiodarone.