Comparison between total thyroidectomy and medical therapy for amiodarone-induced thyrotoxicosis.

CONTEXT It is not known whether total thyroidectomy is more favourable than medical therapy for patients with amiodarone-induced thyrotoxicosis (AIT). OBJECTIVE To compare total thyroidectomy with medical therapy on survival and cardiac function in AIT patients. METHODS Observational longitudinal cohort study involving 207 AIT patients that had received total thyroidectomy (surgery group, n=51) or medical therapy (medical therapy group, n=156) over a 20-year period. AIT types and left ventricular ejection fraction (LVEF) classes were determined at diagnosis of AIT. Cardiac and thyroid function were re-evaluated during the study period. Survival was estimated using the Kaplan-Meier method. RESULTS Overall mortality and cardiac-specific mortality at 10 and 5 years, respectively, were lower in the surgery group than in the medical therapy group (p=0.04 and p=0.01, respectively). The lower mortality rate of the surgery group was due to patients with moderate-to-severely compromised LVEF (p=0.005 vs medical therapy group). In contrast, mortality of patients with normal or mildly-reduced LVEF did not differ between the two groups (p=0.281 and p=0.135, respectively). Death of patients with moderate-to-severe LV systolic dysfunction in the medical therapy group occurred after 82 days (IQR 56-99), a period longer than that necessary to restore euthyroidism in the surgery group (26 days, IQR 15-95; p=0.038). Risk factors for mortality were age (HR=1.036) and LVEF (HR=0.964), whereas total thyroidectomy was shown to be a protective factor (HR=0.210). LVEF increased in both groups after restoration of euthyroidism, above all in the most compromised patients in the surgery group. CONCLUSIONS Total thyroidectomy could be considered the therapeutic choice for AIT patients with severe systolic dysfunction, whereas it is not superior to medical therapy in those with normal or mildly-reduced LVEF.