Biotin treatment mimicking Graves’ disease
Reviewer: Alan Gaby, MD
Author: Kummer S, et al
Reference: Biotin treatment mimicking Graves’ disease. N Engl J Med 2016;375:704-706.
Design: Clinical observation.
Participants: Six children with inherited metabolic diseases.
Study Medication and Dosage: High-dose biotin (2-15 mg per kg of body weight per day) for the treatment of their inherited metabolic disease.
Primary Outcome Measures: Results of routine thyroid function tests.
Key Findings: All of the children had laboratory results that were indistinguishable from those seen in Graves’ disease: elevated levels of free thyroxine (T4) and total triiodothyronine (T3), low levels of thyroid-stimulating hormone (TSH), and elevated levels of anti-TSH receptor antibodies. After a literature search revealed that biotin may interfere with commonly used thyroid function tests, all of the children discontinued biotin. Thyroid hormone (T4 and T3) and TSH levels became normal after 24-48 hours and levels of anti-TSH receptor antibodies became normal within 7 days.
Practice Implications: These findings indicate that supplementation with large doses of biotin can interfere with the results of standard tests for thyroid function, potentially leading to an erroneous diagnosis of hyperthyroidism secondary to Graves’ disease. This misdiagnosis could result in the use of anti-thyroid medications, with deleterious consequences. A recent study suggested that treatment with 100-300 mg per day of biotin (equivalent to 1.4-4.3 mg per kg of body weight per day for a 70-kg person) can improve symptoms in patients with multiple sclerosis. Large doses of biotin (up to 16 mg per day) are also used by some practitioners to treat type 1 and type 2 diabetes, although those doses are less than the amounts reported in the present study to interfere with thyroid function tests. People taking large doses of biotin who need to have their thyroid function tested should discontinue biotin before having the tests.