Clinical outcome of radioiodine treatment of hyperthyroidism: a follow-up study.

OBJECTIVES: To study the clinical outcome of treatment of hyperthyroid patients with radioiodine. DESIGN: Records of patients treated for hyperthyroidism with radioiodine from 1989 to 1992 were examined in 1994, and a questionnaire was sent to patients < or = 70 years with Graves' disease (GD) and toxic nodular goitre (TNG) to obtain information regarding thyroxine substitution, smoking habits and present state of health. SETTING: Outpatients in a thyroid unit; follow-up by primary care. SUBJECTS: Seven hundred and fifty-four patients with hyperthyroidism treated with radioiodine, 327 receiving the questionnaire, 72% response rate. INTERVENTION: Radioiodine treatment using a delivered absorbed dose method, aiming at an absorbed dose to the thyroid of 100-120 Gy. MAIN OUTCOME MEASURES: Statistical analysis of clinical records and results from questionnaire. RESULTS: Only 10% of the patients needed more than one treatment. At the time of follow-up, thyroxine supplementation was given to 178 (93%) of the GD and to 21 (47%) of the TNG patients. Smoking was more common in GD patients than in the general population (44% vs. 26%; P < 0.001). Smoking GD patients experienced eye discomfort more often than smoking TNG patients (53% vs. 7%; P < 0.001). Weight gain after therapy was a problem in 79% of the hyperthyroid individuals. CONCLUSIONS: Few patients needed retreatment and most of the GD patients had thyroxine after 1-5 years after therapy. Smoking patients, especially those with GD, had more eye symptoms. At follow-up, the euthyroid patients still consider themselves having a poorer health than individuals in the general population.