The Long-Term Outcome of Treatment for Graves' Hyperthyroidism

Abstract

<b><i>Background:</i></b> The treatment efficacy of antithyroid drug (ATD) therapy, radioactive iodine (¹³¹I), or surgery for Graves' hyperthyroidism is well described. However, there are a few reports on the long-term total outcome of each treatment modality regarding how many require levothyroxine supplementation, the need of thyroid ablation, or the individual patient's estimation of their recovery. <b><i>Methods:</i></b> We conducted a pragmatic trial to determine the effectiveness and adverse outcome in a patient cohort newly diagnosed with Graves' hyperthyroidism between 2003 and 2005 (<i>n</i> = 2430). The patients were invited to participate in a longitudinal study spanning 8 ± 0.9 years (mean ± standard deviation) after diagnosis. We were able to follow 1186 (60%) patients who had been treated with ATD, ¹³¹I, or surgery. We determined the mode of treatment, remission rate, recurrence, quality of life, demographic data, comorbidities, and lifestyle factors through questionnaires and a review of the individual's medical history records. <b><i>Results:</i></b> At follow-up, the remission rate after first-line treatment choice with ATD was 45.3% (351/774), with ¹³¹I therapy 81.5% (324/264), and with surgery 96.3% (52/54). Among those patients who had a second course of ATD, 29.4% achieved remission (vs. the 45.3% after the first course of ATD). The total number of patients who had undergone ablative treatment was 64.3% (763/1186), of whom 23% (278/1186) had received surgery, 43% (505/1186) had received ¹³¹I therapy, including 2% (20/1186) who had received both surgery and ¹³¹I. Patients who received ATD as first-line treatment and possibly additional ATD had 49.7% risk (385/774) of having undergone ablative treatment at follow-up. Levothyroxine replacement was needed in 23% (81/351) of the initially ATD treated in remission, in 77.3% (204/264) of the ¹³¹I treated, and in 96.2% (50/52) of the surgically treated patients. Taken together after 6-10 years, and all treatment considered, normal thyroid hormone status without thyroxine supplementation was only achieved in 35.7% (423/1186) of all patients and in only 40.3% of those initially treated with ATD. The proportion of patients that did not feel fully recovered at follow-up was 25.3%. <b><i>Conclusion:</i></b> A patient selecting ATD therapy as the initial approach in the treatment of Graves' hyperthyroidism should be informed that they have only a 50.3% chance of ultimately avoiding ablative treatment and only a 40% chance of eventually being euthyroid without thyroid medication. Surprisingly, 1 in 4 patients did not feel fully recovered after 6-10 years. The treatment for Graves' hyperthyroidism, thus, has unexpected long-term consequences for many patients.