Practical treatment with minimum maintenance dose of anti-thyroid drugs for prediction of remission in Graves' disease.
Although many researchers have reported clinical and laboratory parameters for prediction of remission in Graves' disease during or after anti-thyroid drug therapy, there is no reliable one to assure the complete remission. We prospectively examined a practical therapy with minimum maintenance dose of anti-thyroid drugs for prediction of remission in Graves' disease. Fifty-seven patients with Graves' disease were treated with anti-thyroid drugs at the initial dose of 30 mg/day of methimazole (MMI) or 300 mg/day of propylthiouracil (PTU). Then, doses were gradually decreased, and finally discontinued when the patients were able to maintain euthyroid (normal FT4 and TSH) for at least 6 months with the minimum maintenance dose (MMI 5 mg every other day or PTU 50 mg every other day). After discontinuation of drugs, FT4, FT3, TSH and TSH-binding inhibitory immunoglobulin (TBII) were measured every one to two months for the first 6 months and every 3-4 months for the next 18 months to confirm continuous remission. After 2 years of drug cessation, 46 (81%) of 57 patients were in remission and the other 11 patients had relapsed into thyrotoxicosis. At the time of drug discontinuation, the serum concentration of FT4, FT3 and TSH, titers of anti-thyroglobulin antibodies and anti-thyroid microsomal antibodies, goiter size were not different between the remission and relapse groups. At the time of drug cessation, the activities of TBII and thyroid-stimulating antibodies (TSAb) overlapped between the two groups, although they were significantly lower in the remission group than in the relapse group (p<0.01). Forty percent (4/10) of TBII positive patients and 71% (23/32) of TSAb positive patients continued to be in remission. On the other hand, thyrotoxicosis relapsed in 5 (11%) of 47 TBII negative and 2 (8%) of 25 TSAb negative patients. These data indicate that minimum maintenance therapy to keep euthyroid (normal FT4 and TSH) for 6 months is a practical measure for 81% prediction of remission in Graves' disease. The measurement of TBII or TSAb gave little additional information for predicting remission.
Department of Laboratory Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan.
Taku
T
Kashiwai
Yoh
Y
Hidaka
Toru
T
Takano
Ke-ita
KI
Tatsumi
Yukiko
Y
Izumi
Yuki
Y
Shimaoka
Hisato
H
Tada
Keiko
K
Takeoka
Nobuyuki
N
Amino
D000328:Adult; D013956:Antithyroid Agents / Q000008:administration & dosage*; D005260:Female; D006111:Graves Disease / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008713:Methimazole / Q000008:administration & dosage*; D008875:Middle Aged; D011237:Predictive Value of Tests; D011441:Propylthiouracil / Q000008:administration & dosage*; D011446:Prospective Studies; D012008:Recurrence; D012074:Remission Induction
D013956:Antithyroid Agents; D008713:Methimazole; D011441:Propylthiouracil