BACKGROUND
Graves’ disease is the most common cause of hyperthyroidism. Graves’ disease is an autoimmune disorder where the immune system attacks the thyroid and turns it on, causing it to make too much thyroid hormone. This can cause significant health problems, including anxiety, shaking or tremors, increased body temperature (feeling inappropriately hot), a racing heart and atrial fibrillation (abnormal heartbeat). There are several options available for treating hyperthyroidism including antithyroid medications (ATD), such as methimazole and propylthiouracil (PTU), thyroid surgery, and radioactive iodine therapy (RAI) to destroy the thyroid. ATDs are usually the first line of treatment to get thyroid levels back to normal.

Thyroid surgery is a very effective treatment for Graves’ disease, especially with patients with very large thyroid glands. Removing the thyroid resolves the hyperthyroidism but also results in hypothyroidism, because once the thyroid has been removed, the body can no longer make thyroid hormone. This then needs to be treated with thyroid hormone (levothyroxine), which is often easier to control.

In preparing patients for surgery for Graves’ disease, iodine in the form of Lugol’s solution/LS or saturated solution of potassium iodide/SSKI is often used for several days before surgery. This treatment may help lower body thyroid hormone levels and reduce blood flow to the thyroid gland, which can limit blood loss during thyroid surgery. Despite these possible advantages, there is no clear proof showing that iodine treatment before thyroid surgery for Graves’ disease is truly beneficial. This study compares the outcomes of thyroid surgery in people diagnosed with Graves’ disease with or without pre-surgery iodine treatment.

THE FULL ARTICLE TITLE
Schiavone D et al. Role of Lugol solution before total thyroidectomy for Graves’ disease: randomized clinical trial. Br J Surg 2024;111(8):znae196; doi: 10.1093/bjs/ znae196. PMID: 39129619.

SUMMARY OF THE STUDY
Researchers studied 56 adults (ages 18-70) undergoing total thyroidectomy for Graves’ disease at their institution. A total of 29 participants took iodine (Lugol’s solution) for eight days before surgery while 27 participants did not. The care team, including the surgeon, radiologists and pathologists, did not know which patients received iodine before surgery. Only a member of the research team was aware of this information. Researchers collected data on thyroid hormone levels, ultrasound imaging and pathology results to look at the blood supply to the thyroid, blood loss from surgery, length of surgery, and complications after surgery.

The results showed that treatment with iodine before thyroid surgery for Graves’ disease resulted in lower body thyroid hormone levels on the day of surgery. However, this finding did not improve surgery outcomes. There was no significant effect on blood supply to the thyroid gland, the amount of blood loss during or after surgery, the length of surgery or the risk of complications after surgery.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study adds to our understanding of pre-surgery iodine treatment to improve outcomes related to thyroid surgery for treatment of Graves’ disease. Although the authors did learn that iodine treatment can decrease body thyroid hormone levels before surgery, this did not improve outcomes during or after total thyroidectomy. This suggests treatment with iodine may not be necessary before total thyroidectomy for Graves’ disease. This study did have some limitations. The small number of participants may have made it difficult to identify subtle benefits of iodine treatment prior to thyroid surgery for Graves’ disease. Also, the only surgeon involved in this study was highly experienced in thyroid surgery. A larger study with more surgeons having diverse thyroid surgery experience levels might reveal advantages to pre-surgery iodine treatment not identified by this study.

— Stacy Sebastian, MD and Jason D. Prescott, MD PhD

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