The following is a summary of “Iodine‐Induced Hypothyroidism and Long‐Term Risks of Incident Heart Failure,” published in the October 2023 issue of Cardiology by Inoue et al.

The study investigated the correlation between iodine-induced hypothyroidism and the risk of developing heart failure. While most individuals can adapt to high iodine levels and maintain a normal thyroid function, hypothyroidism can sometimes occur after iodine exposure, leading to potential cardiovascular complications, including heart failure. 

This cohort study utilized data from the US Veterans Health Administration between 1998 and 2021, focusing on adults aged 18 years or older with normal thyroid-stimulating hormone (TSH) levels prior to iodine contrast administration. After examining 45,470 veterans (mean±SD age, 61.1±14.1 years, 88% men), it was found that 3361 (7.4%) developed iodine-induced hypothyroidism, and 5685 (12.5%) experienced heart failure during a median follow-up of 3.6 years (interquartile range, 1.9–7.2 years). After adjusting for various risk factors, those who developed hypothyroidism following iodine exposure had an elevated risk of heart failure compared to individuals who maintained normal thyroid function (adjusted hazard ratio [HR], 1.11 [95% CI, 1.01–1.22]). Notably, women showed a higher risk compared to men (adjusted HR: women, 1.65 [95% CI, 1.13–2.40]; men, 1.08 [95% CI, 0.98–1.19]; P for interaction, 0.02). 

These findings underscore the importance of further exploration into this association, especially examining potential sex-specific differences in the risk of incident heart failure in more diverse datasets and populations.

Source: ahajournals.org/doi/10.1161/JAHA.123.030511