Most Graves’ disease treated with antithyroid drugs
Adults with Graves’ disease are more likely to receive drug treatment — despite a higher failure rate — than radioactive iodine therapy or thyroid surgery, according to findings published in Thyroid.
“We are noticing that more people with Graves’ disease are treated with antithyroid drugs than radioactive iodine or surgery; and one fourth of people treated with antithyroid drugs will receive it as long-term — more than 2 years,” Juan P. Brito, MD, MSc, principal investigator for the Knowledge and Evaluation Research Unit in Endocrinology in the division of endocrinology, diabetes, metabolism and nutrition of the department of medicine at Mayo Clinic in Rochester, Minnesota, told Healio. “A significant number of people with Graves’ disease are receiving antithyroid drugs chronically. This way of treatment was known in other countries, particularly in Asia, but unknown here in the U.S.”
Brito and colleagues evaluated the frequency with which antithyroid drugs, radioactive iodine or surgery were utilized as a first-line therapy for adults with Graves’ disease (n = 4,661; mean age, 48 years; 80% women) in the OptumLabs Data Warehouse from 2005 to 2013. Drug failure was defined as participants who initiated radioactive iodine therapy or stopped taking antithyroid drugs for more than 90 days. Radioactive iodine failure was defined as retreatment, including surgery.
Among the entire cohort, 60% received antithyroid drug treatment, 33% received radioactive iodine therapy and 6% underwent surgery. The researchers found that 50% of those who received antithyroid drugs had treatment failure within a median of 6.8 months. In addition, 65% of those who had antithyroid drug treatment failure received antithyroid drug therapy again, whereas 26% went on to receive radioactive iodine therapy and 9% went on to have surgery.
The researchers also found that 7% of those who received radioactive iodine therapy had treatment failure during a median of 3.4 months and that 1% of those who underwent surgery had treatment failure during a median of 3.2 months. In addition, 56% of participants underwent repeat radioactive iodine therapy.
Failure prediction and adverse events
According to the researchers, 6% of those who underwent radioactive iodine therapy, 12% of those who received antithyroid drugs and 24% of those who underwent surgery experienced an adverse event (P < .0001).
“These results should help clinicians and patients discuss the efficacy and safety of treatment options for Graves’ disease,” Brito said. “Particularly, antithyroid drug therapy was presented as treatment option with a horizon of 2 years. Knowing that many patients are receiving antithyroid drugs for more than 2 years could help clinicians frame the idea that antithyroid drugs could turn into a chronic therapy.”
Compared with adults aged younger than 35 years, antithyroid drug treatment failure risk was reduced by 33% for those aged 55 to 64 years (HR = 0.77; 95% CR, 0.64-0.92) and by 21.2% for those aged 65 years or older (HR = 0.788; 95% CI, 0.629-0.985). Risk for drug treatment failure was also higher for black vs. white adults (HR = 1.231; 95% CI, 1.07-1.417), and risk for radioactive iodine failure was higher for women vs. men (HR = 0.549; 95% CI, 0.362-0.833).
“Predictors of treatment failure in this very large cohort suggest that young patients had a higher failure rate than older individuals. This difference might be explained by the fact that younger patients with Graves’ disease have more severe hyperthyroidism at baseline,” the researchers wrote. “This, and the novel finding of a higher rate of failure with antithyroid drugs among African American Graves’ disease patients, needs careful assessment to confirm them, and to then uncover and untangle biological and socioeconomic explanations.” – by Phil Neuffer