Clinical Thyroidology® for the Public

Summaries for the Public from recent articles in Clinical Thyroidology
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GRAVES’ DISEASE
Can TRAb levels predict long-term relapse risk after antithyroid drug therapy for Graves’ disease?

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BACKGROUND
Graves’ disease is an autoimmune condition in which the body produces antibodies (thyroid hormone receptor antibodies, TRAb) that mimic TSH, attacking the thyroid and causing it to secrete high levels of thyroid hormone to produce hyperthyroidism. Graves’ disease is the most common type of hyperthyroidism in the United States. Several options to treat Graves’ disease exist, including anti-thyroid medications, surgery and radioactive iodine therapy. Antithyroid drugs (ATDs) are commonly used in patients with Graves’ disease. The goal of ATD treatment is the patient eventually going into remission and discontinuing the ATDs. However, relapse of Graves’ disease after stopping ATDs, can happen in 50-80% of cases.

TRAb levels are diagnostic for patients with Graves’ disease. They are also related to the risk of recurrence once ATD has been stopped. Other risk factors for relapse include younger age, very large thyroid gland, male gender, having thyroid eye disease, and active smoking history. However, most of the current data on risk factors is limited to recurrent of Graves’ disease within one to two years of stopping ATDs. The goal of this study is to look into recurrence risk of Graves’ disease in 10-year span and determine potential risk factors for relapse.

THE FULL ARTICLE TITLE
Tun NNZ, et al. Ten year outcome of anti-thyroid drug treatment for first episode Graves’ thyrotoxicosis: the predictive importance of TRAb. Clin Endocrinol (Oxf ) 2025;103(5):612-618; doi: 10.1111/cen.70003.

SUMMARY OF THE STUDY
The study was conducted by analyzing previous records at Edinburgh. It included 290 patients diagnosed with Graves’ disease who had an initial TRAb levels done and completed ATD therapy between 2006 and 2011. Subsequent serial thyroid function was monitored for at least ten years after stopping the ATDs after 18 months of treatment. TRAb level was measured at diagnosis in all patients and before stopping ATD. Recurrence was described by the first date of high thyroid function tests.

Of the 290 patients, 191 completed the 10-year follow-up study. Recurrence happened in 103 of 191 (54%) patients within the ten-year span. Of note, more than half (54%) of recurrences occurred in the first year, 72% in the first two years, and 93% within five years. The study observed some characteristics of those with recurrence: younger age, higher TRAb level at diagnosis and at stopping the ATD, and longer time needed to normalize thyroid function levels.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study addressed the likelihood of recurrence in patients with Graves’ disease after ATD therapy. The study concluded that high TRAb levels at the time of diagnosis and upon stopping ATD, and age, may predict recurrence risk. The study also noted most recurrence cases occurred within 1-2 years after diagnosis. This is important, since long-term ATD therapy is becoming increasingly common in the treatment of Graves’ disease.

— Joanna Miragaya, MD

ABBREVIATIONS & DEFINITIONS

Hyperthyroidism: a condition where the thyroid gland is overactive and produces too much thyroid hormone. Hyperthyroidism may be treated with antithyroid meds (Methimazole, Propylthiouracil), radioactive iodine or surgery.

Graves’ disease: the most common cause of hyperthyroidism in the United States. It is caused by antibodies that attack the thyroid and turn it on.

TRAb: antibodies often present in the serum of patients with Graves disease that are directed against the TSH receptor, often causing stimulation of this receptor with resulting hyperthyroidism.

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