Graves’ disease patients who relapsed are twice as likely to become euthyroid following low dose carbimazole treatment compared to radioiodine therapy

• Main Authors: Joseph Anthony Abdullah, Muhd Mikhail, Shahar, Mohammad Arif, A. Wahab, Norasyikin, Mustafa, Norlaila, Sukor, Norlela, Kamaruddin, Nor Azmi
• Format: Conference or Workshop Item
• Language: English
• Published: Malaysian Endocrine & Metabolic Society 2016
• Subjects: RC Internal medicine
• Online Access: http://irep.iium.edu.my/52039/1/graves%20disease%20RAI%20vs%20CBZ.pdf; http://irep.iium.edu.my/52039/; http://www.jmems.org
• Institution: Universiti Islam Antarabangsa Malaysia

Background: The use of low dose antithyroid treatment for relapsed Graves’ Disease has recently been considered a possible viable alternative to ablative therapies such as radioiodine or thyroidectomy. Methods: In this retrospective study we looked at patients with underlying Graves’ Disease who were initially treated with antithyroid drugs between 1-2 years and relapsed following discontinuation of the therapy. Data was collected from those who were subsequently continued on low dose carbimazole therapy(ATD) (≤ 10mg daily) and those who received ablative RAI (12-15mCi). Remission rates and thyroid status at 6 and 12 months post relapse following the initial course of ATD treatment was analysed. Results: A total of 168 patient records were analysed (84 in ATD group and 84 in RAI group). Mean age (years) for ATD and RAI groups were 45.61±13.76 vs 45.89±12.81 respectively, p=0.9. At 6 months mean FT4 (pmol/L) was 18.15±7.21 in the ATD group vs 15.41±7.38 in the RAI group, p=0.03 and the mean TSH (mU/L) was 0.90±1.12 in the ATD vs 13.21±23.84 in the RAI group, p=<0.01; and at 12 months, the mean FT4 was 18.11±5.91 in the ATD vs 14.97±7.87 in the RAI group, p=0.01 and the mean TSH was 0.81±0.93 in the ATD vs 17.27±36.21 in the RAI group, p=0.01. In terms of thyroid status, for the ATD vs RAI group at 6 months, 26.6% vs 44.95% were hyperthyroid, 70.3% vs 17.4% were euthyroid and 3.1% vs 37.7% were hypothyroid, these differences were not statistically significant. However for the ATD vs RAI group at 12 months, 35.6% vs 31.8% were hyperthyroid, 62.7% vs 28.8% were euthyroid and 1.7% vs 39.4% were hypothyroid, all the p-values were statistically significant (p=0.01). Overall remission rate at 12 months post relapse was 30.7% in the ATD group and 35.4% in the RAI group (p>0.05). There was no correlation between rate of remission at 12 months with age, ethnicity, gender, dose of carbimazole nor radioiodine dose. Conclusion: At 12 months following relapse of Graves’ Disease, 62.7% of patients who received low dose carbimazole became euthyroid compared to 28.8% of those who received RAI while 39.4% of those who received RAI were rendered hypothyroid compared to only 1.7% of those who were on low dose carbimazole. In terms of remission rates there was no significant difference between those who underwent low dose carbimazole vs RAI therapy following their first relapse.