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 beta-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; P-upper 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.