# Change in Age of Diagnosis and Demographics of Type 1 Diabetes Mellitus During the COVID-19 Era

## TL;DR

This study found that the average age of type 1 diabetes diagnosis increased during the COVID-19 era, contradicting initial assumptions about younger children being more affected.

## Contribution

The study provides new insights into how the pandemic may have temporarily altered the age distribution of T1DM diagnoses.

## Key findings

- The average age of diagnosis increased by 0.7 years during the pandemic (p=0.025).
- Fewer young children (2–5 years) were diagnosed in 2020, but rates normalized by 2022.
- There was no significant increase in antibody positivity or HbA1c during the pandemic.

## Abstract

Since COVID-19 onset, pediatric endocrinologists have been making an assumption that there was a shift in diagnosis age of type 1 diabetes mellitus (T1DM) to younger children. Younger children are more likely to present in DKA, are more difficult to diagnose and treat, and age at diagnosis can affect prognosis. We performed a retrospective chart review of patients diagnosed with T1DM for 3 years before COVID-19 and the 3 years during COVID-19. Demographics were evaluated using the Chi-squared test for categorical data and Student's t-test or ANOVA for continuous data. During this time, 698 patients were diagnosed with T1DM, with more patients during COVID-19. The average age of diagnosis significantly increased by 0.7 years (p=0.025). There was a significant difference in the distribution of age groups between the two time periods (p=0.0065). There was a significant decrease in new cases among patients between the ages of 2–5 years from 2017 to 2020, a transient finding as they reverted back to previous rates by 2022. New diagnoses between 13 and 18 years were increasing prior to 2020 (7%–23%), subsequently leveling out. Patients were 1.6 times more likely to present in DKA during COVID-19; however, there was no significant change in hemoglobin A1c (HbA1c). There was no significant change in thyroperoxidase (TPO) antibody positivity. There was a significant decrease (p=0.018) in patients with elevated tissue transglutaminase (TTG)-IgA from pre-COVID to post-COVID. Average age at diagnosis in our cohort increased since the start of COVID-19, contradicting previous studies and our hypothesis. The number of new cases increased, and the age distribution changed. There was a significant decrease in number of younger patients in 2020, followed by a normalization of new cases in those 2–5 years old, which may have led to the belief that more toddlers were being diagnosed. The rate of other antibodies did not increase. These results illustrate that changes in demographics may have been short-lived post-COVID-19.