Women represented 85% of the patients in both groups. Patients treated with radioactive iodine therapy were older as compared to patients treated with surgery (average age 64 vs. 47 years) and had more baseline medical problems, including heart disease, such as myocardial infarction and atrial fibrillation, stroke, hypertension, diabetes and cancer. A higher percentage of the patients in the surgery group had thyroid-associated eye disease as compared to the radioactive iodine therapy group (13.2% vs. 8.5%).
After adjusting the analysis for the difference in the patients’ age and comorbid conditions, the surgery group had a lower risk of all-cause mortality and cardiovascular mortality, especially due to heart disease as compared to radioactive iodine therapy group during long-term follow-up. Subgroup analysis, however, revealed that only men and not women had a higher risk of death after radioactive iodine therapy when compared to thyroid surgery. The risk of death due to cancer or other causes was similar for the two treatment groups.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
Surgery for hyperthyroidism was associated with a lower risk of all-cause and cardiovascular death as compared to radioactive iodine therapy during long-term follow-up, particularly in men. This is the first study reporting a difference in the long-term outcome of the two treatment options for hyperthyroidism, especially related to cardiovascular disease in men. However, this study did not include information and did not adjust the analysis for the patients’ thyroid status after the radioactive iodine therapy and surgery, including relapse data, since it is known that persistent hyperthyroidism by itself is associated with an increased all cause and cardiovascular mortality. Additional studies are needed to further evaluate whether hyperthyroid men have better long-term outcomes with thyroid surgery. At present, radioactive iodine therapy is the preferred definitive therapy for Graves’ hyperthyroidism in the US. Importantly, and similar to prior studies, this study showed no increased risk of cancer following radioactive iodine therapy treatment during long-term follow-up.
— Alina Gavrila, MD, MMSC