Endocrine Abstracts

JOINT557

Introduction: Graves´ disease (GD) is the predominant cause of hyperthyroidism. Treatment options include antithyroid drugs (ATD), surgery, and radioactive iodine ablation (RI). After treatment with ATD, both relapse and development of hypothyroidism are common. Although thyroid peroxidase antibodies (anti-TPO) are prevalent in patients with GD, their role in driving relapse or hypothyroidism after treatment in patients with GD remains unclear. This study aimed to determine if patients with anti-TPO at GD diagnosis are more likely to relapse after ATD or RI treatment, and if patients with anti-TPO are at increased risk of developing hypothyroidism post-ATD treatment.

Methods: This was an observational, non-interventional retrospective registry study, which included 712 patients treated for GD at a single center in Sweden during 2002-2018.

Results: After therapy with ATD, there was no difference in relapse rate between patients with (37.0%) or without (38.4%) anti-TPO at GD diagnosis. Age <40 years was a risk factor for relapse after ATD (P < 0.0001). Presence of anti-TPO at diagnosis was associated with reduced relapse rate after RI (13.9% vs. 24.6%; P = 0.049). Development of hypothyroidism after discontinuation of ATD did not correlate with anti-TPO status at diagnosis (with anti-TPO: 17.3%; without anti-TPO: 20.8%).

Conclusion: Anti-TPO positivity at diagnosis of GD did not affect the relapse rate after ATD treatment but could be associated with a better effect of RI. Anti-TPO did not increase the risk of hypothyroidism post-ATD. Understanding these and other risk factors can facilitate treatment choices and help physicians individualize management and follow-up strategies for patients with GD.