title: Optimum duration of antithyroid drug treatment determined by assay of thyroid stimulating antibody in patients with Graves' disease.
abstract: OBJECTIVE
  To determine the optimal duration of antithyroid drug treatment by monitoring serum thyroid stimulating antibody values in patients with Graves' disease.
  
  
  METHODS
  Prospective longitudinal trial of patients with Graves' disease followed up for 24 months after withdrawal of treatment.
  
  
  METHODS
  Tertiary referral centre.
  
  
  METHODS
  A total of 64 consecutive patients with untreated Graves' disease, eight of whom were subsequently excluded. Fifty six patients completed the study.
  
  
  METHODS
  All patients were treated initially with carbimazole 40 mg, then with decreasing doses that maintained a euthyroid state. Treatment was scheduled to continue for 18 months but was withdrawn earlier if serum thyroid stimulating antibody became undetectable.
  
  
  METHODS
  Serum values of thyroid stimulating antibody (assayed by stimulation of human thyroid cells in vitro) and thyroid hormones and thyroid state every three months during treatment and afterwards every six months for 24 months.
  
  
  RESULTS
  In 44 patients serum thyroid stimulating antibody became undetectable during treatment and treatment was withdrawn (median duration of treatment nine months, range 3-18 months). In 12 patients the antibody could be detected during 18 months of treatment. Among the first group of 44 patients initial values of the antibody before treatment were significantly lower than in the second group of 12 patients (median 225% (range 138-1236%) v 570% (250-1480%), p less than 0.001); the incidence of relapse was also lower (41% v 92%, p less than 0.001); and among those who did relapse the disease free interval after treatment was longer (median 12 months v 1 month, p less than 0.001). Moreover, the initial median serum values of thyroid stimulating antibodies were not related to the occurrence of relapse or remission as these did not differ between patients who did and did not have a relapse (median 267% (range 139-1480%) v 220% (range 138-1236%).
  
  
  CONCLUSIONS
  Monitoring of serum thyroid stimulating antibody was a good guide to the duration of treatment as it allowed the treatment period to be considerably shortened in a large group of patients with no loss of efficiency.
authors.affiliation: Clinique Médicale B, Hôpital Sud, Rennes, France.
authors.forename: G
authors.initials: G
authors.lastname: Edan
authors.forename: C
authors.initials: C
authors.lastname: Massart
authors.forename: B
authors.initials: B
authors.lastname: Hody
authors.forename: J Y
authors.initials: JY
authors.lastname: Poirier
authors.forename: M
authors.initials: M
authors.lastname: Lé Reun
authors.forename: J P
authors.initials: JP
authors.lastname: Hespel
authors.forename: G
authors.initials: G
authors.lastname: Leclech
authors.forename: M
authors.initials: M
authors.lastname: Simon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000906:Antibodies / Q000032:analysis*; D002231:Carbimazole / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006111:Graves Disease / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D018828:Immunoglobulins, Thyroid-Stimulating; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011863:Radioimmunoassay; D012008:Recurrence; D013961:Thyroid Gland / Q000276:immunology; D013997:Time Factors
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D018828:Immunoglobulins, Thyroid-Stimulating; D002231:Carbimazole