Amiodarone- induced thyroid dysfunction in an iodine- deficient region
S Ismailov, N Abdusalamova & N Kayumova
Objective: To determine the incidence of thyroid dysfunction in a cohort of patients started on amiodarone therapy at a cardiac clinic in Tashkent, Uzbekistan, which is believed to be an iodine- deficient area.
Methods: Pharmacy records were used to obtain the names of patients who received amiodarone between 2006 and 2009.
Results: The original sample size was 96; 3 patients were excluded to incomplete data and data analysis was completed for 93 patients (21 women and 72 men).
The mean age was 59±15 years (range, 2289). The indication for amiodarone therapy were supraventricular tachycardia (N=64, 68.8%), ventricular tachycardia (N=22, 23.6%), and prophylaxis against tachycardia (N=7, 7.5%). The median duration of amiodarone treatment was 679 days (range, 36425 days) in the entire cohort. The median duration of amiodarone therapy in euthyroid patients was 547 days. The median duration of amiodarone therapy until thyroid disorder developed was 943 days. This was a significantly longer time period compared with euthyroid patients (P=0.05).
Discussion: There were 24 (25.8%) new thyroid dysfunction cases; 18 patients (19.3%) hadthyrotoxicosis, 1 (0.6%) had subclinical hyperthyroidism, 4 (4.3%) had hypothyroidism, and 1 (1.1%) had minor changes in thyroid function.
Conclusions: We found a high incidence of new-onset thyroid dysfunction, similar to the highest rates reported by other investigators. Any additional etiological factors responsible for this in Uzbekistan need to be investigated.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector