Impact of COVID-19 in new-onset type 1 diabetes mellitus in a large Portuguese pediatric diabetes center

Introduction: Our aim was to characterize new-onset type 1 diabetes mellitus (T1D) cases in a pediatric population referred to a large pediatric diabetic center throughout the first year of the COVID-19 pandemic, comparing it to previous years. Methods: Retrospective study including patients under 18 years with new-onset T1D, from March 12th 2020 to March 11(th) 2021. A control group was defined using data on patients under 18 years with new-onset T1D referred to the same hospital in the 3 previous years (from March 2017 to March 2020). Data was analyzed using SPSS. A p value of 0.05 was used as threshold of significance. Results: Between March 12(th) 2020 and March 12(th) 2021, 44 patients were diagnosed with new-onset T1D. The control group included 96 patients, resulting in an incidence of 32 cases/year (37.5% rise). January 2021 was the month with the higher number of diagnosis, corresponding to the peak of novel SARS-CoV-2 infections. During the pandemic, new-onset T1D cases in children under 2 years-old doubled, when comparing to mean incidence in previous years. Median delay to diagnosis was not significantly different from previous years. Diabetic ketoacidosis (DKA) at presentation was present in 50% of cases that were diagnosed after lockdown, increasing substantially from previous years (38.5%). DKA's severity was also significantly higher (40.9%, p=0.04), as were Intensive Care Unit admission (13.6%, p=0.04). Conclusion: Despite the existance of molecular pathways that could lead to islet cell injury, the role of the new coronavirus in the pathogenesis of DKA and T1D onset is still unclear. Disease severity could also be related to a higher proportion of younger children.