Major adverse CV event risk lower after surgery, radioactive iodine for hyperthyroidism
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Key takeaways:
- Of adults with hyperthyroidism, 93.9% were treated with antithyroid drugs.
- Adults who underwent surgery or radioactive iodine therapy had a lower risk for a major adverse CV event.
Adults with hyperthyroidism who undergo surgery or receive radioactive iodine therapy have a lower risk for major adverse cardiovascular events than those receiving antithyroid drugs, according to data published in JAMA Network Open.
“We found that over a mean follow-up of 4.4 years, hyperthyroid patients treated with surgery had a 47% lower risk of death and a 24% lower risk of major adverse CV events than patients treated with medication,” Elizabeth N. Pearce, MD, MSc, a Healio | Endocrine Today Editorial Board Member and professor of medicine in the section of endocrinology, diabetes and nutrition at Boston University Chobanian & Avedisian School of Medicine, told Healio. “The patients treated with radioactive iodine had a 55% lower likelihood of major adverse CV events compared to the patients treated with medication.”
Pearce and colleagues conducted a population-based cohort study with data from 114,062 adults aged 20 years and older who were newly diagnosed with hyperthyroidism from 2011 to 2020 (73.2% women; mean age, 44.1 years). Data were obtained from the Taiwan National Health Insurance Research Database. Adults were divided into three groups based on treatment received within 18 months of diagnosis. The antithyroid drug group included adults who only received antithyroid drugs. Adults in the radioactive iodine and surgery groups included those who received antithyroid drugs before treatment as long as radioactive iodine and surgery were performed within 18 months of diagnosis. The primary outcomes were major adverse CV events and all-cause mortality. Major adverse CV events were a composite of acute myocardial infarction, stroke, heart failure and CV morality. Each individual CV component and hyperthyroidism relapse were secondary outcomes. Follow-up continued until a CV event occurred, death, insurance withdrawal or the end of the study on Dec. 31, 2020.
Of the study group, 93.9% received antithyroid drugs alone, 5.1% underwent thyroid surgery and 1.1% received radioactive iodine therapy.
During a mean follow-up of 4.4 years, adults receiving radioactive iodine (HR = 0.45; 95% CI, 0.22-0.93; P = .03) or undergoing thyroid surgery (HR = 0.76; 95% CI, 0.59-0.98; P = .04) had a lower risk for a major adverse CV event than those receiving antithyroid drugs. Those who underwent surgery had a lower risk for heart failure (HR = 0.33; 95% CI, 0.18-0.59; P < .001), CV mortality (HR = 0.45; 95% CI, 0.26-0.79; P = .005) and all-cause mortality (HR = 0.53; 95% CI, 0.41-0.68; P < .001) than the antithyroid drug group.
“The improved outcomes observed in the study with surgery or radioactive iodine may have been related to more prompt and complete resolution of hyperthyroidism than was achieved with medication,” Pearce said.
Hyperthyroidism relapse occurred in 63.5% of adults receiving antithyroid drugs, 38.2% of those receiving radioactive iodine and 17.3% of adults who underwent surgery. The odds for hyperthyroidism relapse were lower with radioactive iodine (OR = 0.43; 95% CI, 0.38-0.48; P < .001) and surgery (OR = 0.08; 95% CI, 0.08-0.09; P < .001) compared with antithyroid drugs.
“The selection of therapy for hyperthyroidism needs to be individualized — this is not one-size-fits-all,” Pearce said. “Thyroid surgery or radioactive iodine treatment may be better treatment options than long-term antithyroid drug use in patients with hyperthyroidism who also are at high risk for CVD.”
Pearce said large prospective studies are needed to better understand the long-term risks with different hyperthyroidism treatments.
For more information:
Elizabeth N. Pearce, MD, MSc, can be reached at elizabeth.pearce@bmc.org.
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