Remission rates with antithyroid drug therapy: continuing influence of iodine intake?

We retrospectively reviewed the therapeutic efficacy of antithyroid drugs for Graves disease. Sixty-nine patients were divided into three categories according to their response: 28 (40.6%) were unable to achieve a remission; 6 (8.7%) achieved a remission and subsequently had a relapse; and 35 (50.7%) were able to sustain a remission. The mean duration for sustained remissions was 33 months. Our earlier review of outcome of antithyroid therapy showed markedly reduced remission rates, which appeared to be related to increases in dietary iodine intake. Although the greater percentage of patients entering remission today is in marked contrast to the 1973 report, average dietary iodine content has been decreasing. A continuing role for antithyroid drugs should be maintained as an option in the management of Graves disease. Daily dietary iodine intake may influence the anticipated remission rate after antithyroid drug therapy.