Children diagnosed with presymptomatic type 1 diabetes through public health screening have milder diabetes at clinical manifestation.

Aims/hypothesis: We aimed to determine whether disease severity was reduced at onset of clinical (stage 3) type 1 diabetes in children previously diagnosed with presymptomatic type 1 diabetes in a population-based screening programme for islet autoantibodies.

Methods: Clinical data obtained at diagnosis of stage 3 type 1 diabetes were evaluated in 128 children previously diagnosed with presymptomatic early-stage type 1 diabetes between 2015 and 2022 in the Fr1da study and compared with data from 736 children diagnosed with incident type 1 diabetes between 2009 and 2018 at a similar age in the DiMelli study without prior screening.

Results: At the diagnosis of stage 3 type 1 diabetes, children with a prior early-stage diagnosis had lower median HbA (51 mmol/mol vs 91 mmol/mol [6.