Abstract: Abstract: Objective To analyse effects of the serum levels of thyroid peroxidase antibodies (TPOAb) on antithyroid drugs (ATD) treatment in patients with incipient Graves disease (GD). Methods A total of 121 patients with incipient GD, who were used anti thyroid drugs for 12 months, were included in this study. Patients were dvided into two groups: TPOAb negative group (TPOAb≤35 IU/mL, n=49) and TPOAb positive group (TPOAb > 35 IU/mL, n=72). According to the degree of TPOAb drops the TPOAb positive group was sub-divided into low level positive group (35 IU/mL < TPOAb≤200 IU/mL, n=19), medium level positive group (200 IU/mL＜TPOAb≤ 500 IU/mL, n=20), high level positive group (500 IU/mL＜ TPOAb≤1 000 IU/mL, n=13), and very high level positive group (TPOAb > 1 000 IU/mL, n=20). The ATD total dosage for 12 months and thyroid-stimulating hormone (TSH), which returned to normal rate after treatment of 3, 6 and 12 months, were compared between groups. Results ATD total dose was lower in TPOAb positive group (1 743.82±265.38) mg than that of negative group (1 889.18 ±125.51) mg. The ATD total dosages were (1 759.71±230.29) mg, (1 793.75±299.02) mg, (1 731.54± 236.44) mg and (1 710.00±290.73) mg for low level TPOAb positive group, medium level TPOAb positive group, high level TPOAb positive group, and very high level TPOAb positive group respectively. The recovering ratio of TSH was significantly higher in TPOAb positive group than that of TPOAb negative group after 3-month treatment (P < 0.05). Conclusion TPOAb positive serum can lead to shorten the course of ATD treatment and reduce the total amount of ATD treatment in GD patients.

Key words: Graves disease, peroxidase, autoantibodies, thyroid gland, antithyroid agents, drug dosage