The incidence of new-onset type 1 diabetes has been increasing globally each year. Researchers at a children's hospital in California observed that the incidence during the COVID-19 pandemic in 2020 and 2021 appeared to have increased compared with previous years. They performed a six-year retrospective review of medical records to determine whether the increase was significant and whether more children had diabetic ketoacidosis at presentation or required admission to the pediatric ICU.

The researchers collected data on patients younger than 19 years of age admitted to a California hospital who had at least one positive type 1 diabetes antibody titer. On admission, patients were tested for acute COVID-19 infection but not for antibodies to diagnose prior infection.

From March 19, 2020, to March 18, 2021, 187 children were admitted with new-onset type 1 diabetes compared with 119 in the previous year, an increase of 57%. New cases during the COVID-19 year exceeded the number anticipated based on data from the previous five years. Only four of 187 patients had COVID-19 infection at presentation. During this period, there was a significant increase in the frequency of diabetic ketoacidosis at the time of type 1 diabetes diagnosis, with 93 of 187 children (49.7%) requiring insulin infusion compared with 261 of 641 (40.7%) in the previous five years. No differences were observed in age at presentation, body mass index, glycated hemoglobin levels, or percentage of patients requiring admission to the pediatric ICU.

A limitation of the study was the lack of testing for COVID-19 antibodies at the time of diagnosis. Also, there was no population denominator. The authors point out, however, that the number of children residing in the surrounding area and the number of children seen in the pediatric endocrine clinic didn't change substantially, so it's unlikely the increase in type 1 diabetes diagnoses during the pandemic reflected changes in referral number or pattern.