With James V. Hennessey, MD, and Robert J. McConnell, MD
People who are diagnosed with hyperthyroidism, in particular, Graves’ disease, are treated with antithyroid medication, radioactive iodine (RAI) therapy, or surgery, but the long-term effects of each choice are not well known.
In one study,1 the investigators report that some individuals appear more susceptible to events related to heart disease than others based on outcomes determined after these patients who had hyperthyroidism and received treatment to manage their Graves’ thyroiditis, looking at what factors might provide a better understanding about the apparent risk of cardiovascular disease.
The findings seemed to indicate that patients who became hypothyroid–either after receiving antithyroid drugs or treatment with radioactive iodine (RAI) –have better survival rates than patients who appear well managed but who still experience some degree of thyroid toxicity.1
Does the Treatment Choice for Hyperthyroidism Influence Risk of Heart Disease?
To gain a clearer understanding of the impact that treatment choice might have on a person with Graves’ thyroiditis, a team of researchers at Cardiff University in the United Kingdom (UK) conducted a retrospective cohort study to examine best approaches for hyperthyroid management;2 their findings were published in Lancet Diabetes and Endocrinology.
In the Cardiff-led study, 4,189 patients who were diagnosed with Graves’ disease from 1998 to 2013 as determined by results of a blood test, were included and divided into two groups:
- Group 1 represented individuals who were treated with antithyroid medications (n=3587) or RAI.
- Group 2 included patients who achieved euthyroid or hypothyroid status (n=250) and those who had improved but were still experiencing hyperthyroidism (n=182).
- There were four times as many controls—people with no thyroid dysfunction—followed as the total number of patients in the study.
- Patients who had surgery were not included in the study as there were too few of them.
After following all of the participants for one year, the investigators found that those who had achieved a complete reversal of their hyperthyroidism experienced less illness and fewer deaths than patients whose treatment appeared incomplete.2
The mode of treatment didn’t matter, according to James V. Hennessey, MD, associate professor of medicine at Harvard Medical School and an endocrinologist at Beth Israel Deaconess Medical Center in Boston, Massachusetts who wasn’t involved in the study but agreed to review the findings for EndocrineWeb.
Patients who received either antithyroid drugs or those who were treated with radioactive iodine all had better overall outcomes than patients not achieving a symptom-free status after receiving treatment. However, the authors noted that patients who were treated successfully with RAI often received treatment earlier than those treated with RIA who remained with some degree of hyperthyroidism an average of 80 days longer.
Radioactive Iodine Likely Best Treatment for Heart Health
From the findings, it seems that patients with Graves’ disease have a 23% greater risk of experiencing a cardiovascular event (eg, heart attack) when compared to those in the control group.2 However, patients who have early and successful treatment of their hyperthyroidism can reduce their risk of experiencing cardiac events by 50%.
“We already knew that radioactive iodine was safe and effective,” Dr. Hennessey tells EndocrineWeb. “But this helps us to realize that a patient needs to use a dose that will induce to some degree hypothyroidism so that we can easily control the patient’s function with thyroid replacement.”
Dr. Hennessey said that what makes this study worth paying attention to is the large number of patients with Graves’ disease who were included in the study rather than just individuals who had other types of hyperthyroidism.
One issue that remains a problem, however, is the fear that the word “radioactive” can elicit in patients, he said. With access to the Internet and so much information (and misinformation), Dr. Hennessey said that many patients are very averse to having RAI given concerns that really are not well founded.
Given the clear benefits seen among those agreeing to have their Graves’ hypothyroidism treated with radioactive iodine may be that it will help assuage the worries and fear. Patients are encouraged to speak with their doctor about any lingering concerns so you can make a well-informed decision about the best course of treatment for you.
Questions Regarding Benefits of the Right Treatment Option Remain
Another concern not addressed by the authors relates to the use of levothyroxine to treat their hyperthyroidism. It seems the authors did not track patients who may have been treated with LT4 to combat their hyperthyroid condition during the year participants were followed. That might be something that could impact these findings as well, Dr. Hennessey said.
For years, Dr. Hennessey has treated patients with hyperthyroidism with a dose of RAI about 10% higher than the minimum calculated for them. The goal, he says, is to render patients slightly hypothyroid and then treat them with levothyroxine in order to bring their TSH level back into the normal range. The one-year post-treatment experiences of the patients in this study reaffirms his belief that RAI is the best treatment for his patients.
“Study after study has come up short in finding a precise dose for radioactive iodine therapy,” he says, “Most doses leave some patients with persistent thyroid toxicity [meaning still overactive]; and that’s not healthy. Using the 10-15 mCi range is much more likely to result in a cure. We don’t want patients to remain hyperthyroid for a long period of time.”
“Getting the hyperthyroid patient to euthyroid status as quickly and efficiently as possible is the best approach to thyroid disease management, especially for patients over age 50 years,” says Robert J. McConnell, MD, a professor of medicine at Columbia University Medical Center and medical director of the New York Thyroid Center, “since they are at greatest risk for cardiovascular events, in general.”
RAI May Not Be Best When Treating Graves’ Disease in Older Adults
Dr. McConnell tells EndocrineWeb that he has some concerns about using the radioiodine treatment, for hyperthyroidism, particularly in older patients, because as they are more likely to develop Graves’ ophthalmology, an inflammatory thyroid eye disease.3
Given this possible complication, Dr. McConell says that in the future, it would be beneficial to see some good research on how to determine which patients will be able to achieve hyperthyroid disease remission with antithyroid drug therapy alone. “Unfortunately, there is no good way that we know of to achieve this yet.”
Last updated on 04/08/2019
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