Could increased thiamazole sales among children in Belgium during the pandemic indicate a surge in Graves’ disease cases?

This study aimed to assess the thiamazole sales in the paediatric population in Belgium from 2016 to 2023 in Belgium using the data f provided by The National Institute for Health and Disability Insurance (NIHDI). It also assessed during the same period the number of pediatric patients diagnosed with pediatric AITD in a single-center setting. We retrospectively analyzed data from the NIHDI national database, collecting the daily defined dose (DDD) and the number of pediatric patients treated with thiamazole. Additionally, a single-center study was conducted including children newly diagnosed HT or GD between January 1, 2016, and December 31, 2023. Patients were categorized into three groups: pre-pandemic (2016–2019), pandemic (2020–2022), and post-pandemic (2023). An increase in thiamazole prescriptions was observed, peaking in 2022 (88,500 DDD/year for Group 2 vs. 77,295 DDD/year for Group 1, p = 0.001). At our center, among the 43 newly diagnosed patients with GD, a significant rise in GD diagnoses was noted during the pandemic (10 cases/year) compared to the pre- and post-pandemic periods (3 cases/year, p = 0.037). In contrast, the number of HT cases remained stable across all three periods, with a total of 141 patients. No significant differences in disease severity were found between patients diagnosed before or during the pandemic. Pediatric thiamazole prescriptions at the national level and GD diagnoses at the local level increased during the COVID-19 pandemic, while HT incidence remained unchanged. Although a direct causal link with SARS-CoV-2 cannot be confirmed, these findings suggest that the pandemic may have influenced GD incidence, warranting further investigation. Disease severity did not differ between patients diagnosed before and during the pandemic.