The American Thyroid Association (ATA) has revised its guidelines for the treatment of thyrotoxicosis, including hyperthyroidism.1
For the updated guidelines, the ATA convened a task force of 11 experts from North America, South America, and Europe to review evidence that has emerged in the 5 years since publication of the previous set of guidelines.
“There have been new developments in thyroid research, and the new guidelines reflect this, as well as changes in practice trends,” Marilyn Tan, MD, an endocrinologist and clinical assistant professor at Stanford University School of Medicine in California, told Endocrinology Advisor. “It is important to continue reassessing our routine practices to make sure we are optimizing patient safety, outcomes, and health care utilization.”
In an interview with Endocrinology Advisor, Douglas S. Ross, MD, chair of the task force and professor of medicine at Harvard Medical School and co-director of the Thyroid Clinic at Massachusetts General Hospital in Boston, highlighted 5 of the major changes in the new guidelines, which consist of 124 recommendations.
1. New paradigms for determining the etiology of thyrotoxicosis that make use of thyrotropin receptor antibodies (TRAb)
“There is a shift away from starting with a radioactive iodine (RAI) uptake and scan as the first step for determining the etiology of thyrotoxicosis,” according to Dr Tan. If it is not evident from the clinical presentation and initial biochemical evaluation—as in the case of a patient with a nonnodular thyroid and no apparent orbitopathy, for example—then diagnostic testing should be conducted. This may include measurement of TRAb, radioactive iodine uptake, or ultrasonography to measure thyroidal blood flow.1 A thyroid scan is indicated if toxic adenoma or toxic multinodular goiter is suspected.1
2. The use of TRAb for monitoring the response to antithyroid drugs
Adverse effects of antithyroid drugs, which were found to affect an estimated 13% of patients in a systematic review,2 range from minor allergic reactions to serious reactions that include agranulocytosis, vasculitis, and hepatotoxicity. According to the new guideline, such patients’ thyroid status should be monitored to inform any necessary dosage changes, and TRAb levels should be measured before the end of antithyroid drug therapy to identify patients with a higher chance of remission.1
“Patients with persistently high TRAb could continue [antithyroid drug] therapy (and repeat TRAb after an additional 12-18 months) or opt for alternate definitive therapy with RAI or surgery,” wrote the authors.
3. Safety data supporting the use of long-term antithyroid drug therapy
“There is less of a push for definitive therapy for hyperthyroidism—such as radioactive iodine ablation or surgery,” said Dr Tan. “Previously, due to safety concerns, it was recommended that the time on antithyroid drugs be limited. It is now more accepted to be on antithyroid drugs long-term.”
In one study of patients with Graves’ disease, methimazole doses of 2.5 mg/d to 10mg/d taken for a mean duration of 14 years were found to be safe and effective,3 and another study reported that long-term use of low-dose antithyroid drugs resulted in better outcomes and fewer side effects than RAI.4