Remission of Grave's disease after oral anti-thyroid drug treatment

Objective: To evaluate remission rate of anti-thyroid drug treatment in patients with Grave's disease, and to study the factors associated with remission. Study Design: A cross sectional study. Place and Duration of Study: The Endocrine Department of the Aga Khan University Hospital, Karachi from 1999 to 2000. Methodology: Seventy four patients of Grave's disease were recruited who were prescribed medical treatment. Graves' disease was diagnosed in the presence of clinical and biochemical hyperthyroidism along with anti-microsomal (AMA) and anti-thyroglobulin antibodies (ATA) and thyroid scan. These patients were prescribed oral anti-thyroid drugs using titration regime and followed at 3, 6, 12 and 18 months. Patients were categorized into two groups: "remission group" and "treatment failure group" and results were compared using a chi-square test, t-test and logistic regression model with significance at p < 0.05. Results: A majority of the patients were females (62.6%, n=46). During the follow-up period of 18 months, 41.9% patients went into remission. Univariate analysis showed that the initial free T4 level was significantly different (p < 0.05) in patients in remission and treatment failure groups. Multivariate analysis showed only initial free T4 level was a significant predictor of outcome. Positive AMA patients (n=27) had higher treatment failure (odds ratio: 2.55: 95%, CI 0.69-9:31), although the difference was not statistically significant (p = 0.13). Conclusion: Remission rates with oral anti-thyroid agents is markedly high. Patients should be offered alternate treatment options to those who do not enter remission during a period of 12-18 months of treatment, those who develop relapse, and those who have aggressive disease on initial presentation.