Frequency of Autoantibody-Negative Type 1 Diabetes in Children, Adolescents, and Young Adults During the First Wave of the COVID-19 Pandemic in Germany.

OBJECTIVE The aim of this study was to investigate the frequency of newly diagnosed type 1 diabetes without evidence of autoimmunity and the respective frequencies of ketoacidosis in children, adolescents, and young adults during the coronavirus disease 2019 (COVID-19) pandemic in Germany compared with the previous decade. RESEARCH DESIGN AND METHODS Based on data from the German Diabetes Prospective Follow-up Registry (DPV), we compared data from 715 children, adolescents, and young adults, newly diagnosed with type 1 diabetes during the COVID-19 pandemic in Germany between 1 March and 30 June 2020, with data from 5,428 children, adolescents, and young adults of the same periods from 2011 to 2019. Adjusted differences and relative risks (RRs) of negative β-cell autoantibody test results and diabetic ketoacidosis were estimated using multivariable log-binomial regression analysis. An upper noninferiority test (margin 1%) was applied to evaluate whether the autoantibody-negativity rate in 2020 was not higher than that in 2011 to 2019. RESULTS The estimated frequencies of autoantibody negativity in 2020 and 2011–2019 were 6.6% (95% CI 5.1–8.4) and 7.2% (95% CI 6.5–8.0), respectively, with an absolute difference of −0.68% (90% CI −2.07 to 0.71; Pupper noninferiority = 0.023). The increase of the estimated frequency of diabetic ketoacidosis during the COVID-19 pandemic was similar between autoantibody-negative and -positive type 1 diabetes (adjusted RRs 1.28 [95% CI 0.80–2.05] and 1.57 [1.41–1.75], respectively). CONCLUSIONS This study found no evidence that the COVID-19 pandemic leads to a significantly increased number of new cases with autoantibody-negative type 1 diabetes in children, adolescents, and young adults. In addition, autoantibody-negative type 1 diabetes showed no particular susceptibility to ketoacidosis, neither before nor during the pandemic.