Long-term outcomes of treatment of hyperthyroidism in Ireland.

We investigated the long-term outcome of treatment in 159 patients with hyperthyroidism first seen between 1979 and 1992. Median duration of follow-up was 10 1/2 years. We also inquired into current practice for the follow-up of hyperthyroidism by other endocrinologists in Ireland. Seven cases of unrecognised hyperthyroidism (4 per cent) and one of unrecognised hypothyroidism were identified. Among patients with Graves' disease, of those treated with an antithyroid drug, 28 per cent were in remission, 68 per cent had relapsed and 4 per cent had become hypothyroid. Of those treated by sub-total thyroidectomy, 31 per cent were in remission, 19 per cent had relapsed, 19 per cent were hypothyroid and 31 per cent were sub-clinically hypothyroid. Among patients treated with radioiodine, 19 per cent were euthyroid, 3 per cent were still hyperthyroid and three-quarters had become hypothyroid. In contrast, after radioiodine for toxic nodular goitre, 63 per cent were euthyroid and only 32 per cent had become hypothyroid (Chi Squared v. Graves' disease, P = 0.001). Of 73 patients receiving thyroxine replacement, plasma TSH was normal in only 41 per cent, although 82 per cent of patients had been seen by the family doctor within the previous 12 months. Seven of 17 other endocrinologists undertook long-term follow-up of hyperthyroid patients in their specialist clinics but none was using a computerised system to co-ordinate this. The findings confirm that careful follow-up is required for all hyperthyroid patients. The family doctor is well positioned to undertake this, but education and auditing are required.