Endocrine Abstracts

Background: Autoimmune Graves’ disease is the most common cause of hyperthyroidism. Medical management of Graves’ thyrotoxicosis with thionamides is complicated by a reported relapse rate of about 60%.

Aims: The aims of this study were to determine the relapse rate of patients treated with drugs as first line treatment for Graves’ disease and to assess the impact of patient demographics, serum free T4(fT4) and clinical characteristics on relapse rate.

Methods: All patients diagnosed with Graves’ thyrotoxicosis in 2005 at the James Cook Hospital, Middlesbrough, UK, were identified and data on patient demographics, fT4 level, presence of goiter and opthalmopathy, first line treatment and duration and relapse status were obtained from case records. Student’s t-test and Chi-square test were used to determine any statistical significance between correlations.

Results: 38 patients (87% female) with Graves’ thyrotoxicosis were identified. Mean age at diagnosis was 47.7 years and mean fT4 level was 57.5 pmol/L. 87%( n=33) patients were started on a thionamide drug (predominantly Carbimazole) as first line therapy. 4 patients received radioiodine as the first option and 1 patient opted for total thyroidectomy. Mean duration of drug therapy was 19.9 months (IQR 15–24.2) and 15.6 months (IQR 11–16.5) for block and replace and dose titration regimes respectively.27 patients were euthyroid on stopping therapy and of these 9 patients’ thyrotoxicosis relapsed. The estimated relapse rate following drug therapy was 39.1% (95% CI, 19.2–59.1). Statistically significant parameters predicting increased risk of relapse were female gender (P=0.01), older age (P=0.04) and fT4 >70 pmol/L (P=0.02) at presentation.

Conclusion: Relapse rate at 5 years in this cohort was 39% which is lower than that reported in the literature. Female gender, younger age and fT4>70 pmol/L at presentation were significant predictors of increased risk of relapse.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.