Comparison of mortality and cardiovascular morbidity following treatment for hyperthyroidism: A systematic review and bayesian network meta-analysis.

Introduction: Therapeutic approaches for hyperthyroidism, namely antithyroid drugs, radioiodine, and thyroidectomy, aim to restore normal thyroid function while minimizing harm. However, the difference in outcomes related to mortality and cardiovascular diseases between them remains controversial.

Methods: PubMed, Embase, Cochrane Central, and Web of Science were searched for randomized controlled trials and cohort studies that compared any of the three supracited therapeutic approaches between themselves. A Bayesian model estimated hazard ratios (HR) with 95% credible intervals (CrI) using a random-effects model. Treatments were ranked by surface under the cumulative ranking curve (SUCRA).

Results: Eight cohort studies encompassing 172,585 hyperthyroid patients were included. Thyroidectomy was associated with lower all-cause mortality compared to antithyroid drugs (HR 0.442; 95% CrI 0.244-0.783) but not radioiodine (HR 0.675; 95% CrI 0.424-1.296). No significant differences were observed for cardiovascular mortality when comparing thyroidectomy to antithyroids (HR 0.440; 95% CrI 0.177-1.127) and radioiodine (HR 0.580; 95% CrI 0.342-1.064). For major cardiovascular events (MACE) there was no significant difference between radioiodine vs. antithyroids (HR 0.557; 95% CrI 0.265-1.006) and thyroidectomy (HR 0.784; 95% CrI 0.347-1.917). Thyroidectomy did not reduce heart failure risk vs. antithyroids (HR 0.353; 95% CrI 0.115-1.251) and radioiodine (HR 0.426; 95% CrI 0.131-1.749). SUCRA rankings suggested thyroidectomy as the best treatment concerning mortality and heart failure, while radioiodine ranked highest for MACE.

Conclusion: Thyroidectomy and radioiodine may offer better long-term cardiovascular and mortality outcomes compared to antithyroid drugs. Further studies with proper designs are needed to verify the nature of these associations.