Outcome of Patients With Graves' Disease After Long‐term Medical Treatment Guided by Triiodothyronine (T3) Suppression Test

Abstract

The value of the T3 suppressed 20-min uptake test for the prediction of post-treatment outcome was studied in 193 unselected patients with Graves' disease treated with thionamide drugs and T3. One hundred and twenty-nine of 193 patients were studied previously and followed thereafter (Group A). Sixty-four were newly treated patients: thirty-three (Group B) were treated at the same hospital as Group A; thirty-one (Group C) were treated at another hospital. In total 126 patients out of 193 satisfied our criteria for suppression (total suppression rate, 65%). The suppression rate for new patients (55% in Group B, 52% in Group C) was similar to that for Group A in 1977 (49%) after comparable duration of treatment. The suppression rate for Group A increased with prolongation of the treatment period (49% in 1977 and 71% in 1981). As to the time course of suppression, it was observed that about two-thirds of the suppressed patients satisfied the criteria for suppression within 3 years of starting treatment. The number of suppressed patients per year decreased thereafter as the treatment periods increased. However, the yearly suppression rate did not decrease with time. The time course of suppression in each patient could not be predicted from the results of initial thyroid function tests. The overall remission rate among the 120 suppressed patients followed for 1-13 (mean, 4) years was 96%, which was almost equal to the value obtained in Group A in 1977 (95%) with the average follow-up period of 2 years. Among the 46 patients in Group A followed for 5-13 (mean, 7) years, no increase in relapse was observed with prolonged follow-up periods. Examination on the relationship between the duration of treatment and the post-treatment outcome revealed that, as a whole, the duration of treatment for the patients with relapse were rather short as compared with those for the patients in remission. These results confirm the usefulness of our T3 suppression test for predicting sustained remission of Graves' disease after treatment, and clearly indicate that long-term medical therapy could increase the number of remissions in patients with Graves' disease.

Serum Thyroid-Stimulating Antibody, Thyroglobulin Levels, and Thyroid Suppressibility Measurement as Predictors of the Outcome of Combined Methimazole and Triiodothyronine Therapy in Graves' Disease

“…A high remission rate was obtained also when ATD was withdrawn after the T3 suppression returned to normal, but it required a longer period (up to 8 years) of treatment (24). Although no predictive value was noted in the present study, most of our remission patients were suppressible, and the T3 suppression test was useful for monitoring combined therapy.…”

Reduction of the Risk of Relapse After Withdrawal of Medical Therapy for Graves' Disease

“…Clearly, however, a significant proportion of patients cannot be cured with a course of thionamide. This had been the case, for instance, in 67 of the 193 patients treated by Yamamoto et al (11) for more than 8 years.…”

“…In a study by Edan and coworkers (13), 44 of 64 patients tested every 3 months in whom therapy was stopped when TRAb (TSAb) became negative were maintained on antithyroid drug for an average of 9 months (range, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Among them, the relapse rate was 41% compared to a rate of 92% for the patients who remained TSAb-positive after 18 months of antithyroid drug treatment (13).…”

Drug discontinuation after treatment with minimum maintenance dose of an antithyroid drug in Graves' disease: a retrospective study on effects of treatment duration with minimum maintenance dose on lasting remission

“…The timing of ATD cessation is difficult to determine because there are no measures for accurately evaluating the activity of Graves' disease. For this purpose, the triiodothyronine (T3) suppression test [10,11], thyroid releasing hormone test [12,13], T3/thyroxine (T4) ratio [14] and serum thyroglobulin [15,16] and thyroid stimulating hormone (TSH) receptor antibody (TRAb) [2,3,[17][18][19][20][21][22][23][24] levels have been used, but acceptable results have not been obtained.…”