New-Onset Type 1 and Type 2 Diabetes Among Korean Youths During the COVID-19 Pandemic

Importance: Whether COVID-19 contributes to youth-onset diabetes is controversial, and research in Asia is lacking. Objective: To explore the incidence and severity of diabetes among youths during the COVID-19 pandemic in South Korea. Design, Setting, and Participants: This cohort study used claims data for January 1, 2017, through February 28, 2022, from the National Health Insurance Service database in South Korea. The incidence of type 1 diabetes (T1D) and type 2 diabetes (T2D) in patients younger than 20 years during the pandemic was analyzed and compared with that during the prepandemic period. The study included incident cases of T1D identified by at least 2 diagnosis codes with at least 2 insulin prescriptions within 1 year and T2D identified by at least 2 diagnosis codes with at least 2 prescriptions of diabetes medication within 1 year. Analyses were performed between January 29 and September 2, 2024. Exposures: COVID-19 pandemic and SARS-CoV-2 infection. Main Outcomes and Measures: The primary outcome was incidence of T1D and T2D, and secondary outcomes included the rate of diabetic ketoacidosis (DKA) and association of new-onset diabetes with SARS-CoV-2 positivity. Results: The study included 2599 patients with T1D (mean SD age, 12.0 4.8 years; 1235 47.5% male) and 11 040 patients with T2D (mean SD age, 16.0 2.8 years; 6861 62.1% male). During the pandemic, the incidence rate ratios were 1.19 (95% CI, 1.10-1.29) for T1D and 1.41 (95% CI, 1.36-1.46) for T2D. The incidence rate of DKA at diagnosis increased during the first pandemic year compared with the prepandemic period (T1D, 42.8% 95% CI, 38.5%-47.0% vs 31.3% 95% CI, 29.0%-33.7%, respectively; T2D, 6.0% 95% CI, 5.0%-7.1% vs 2.9% 95% CI, 2.5%-3.3%, respectively) but returned to prepandemic levels in the second pandemic year (T1D, 34.5% 95% CI, 30.6%-38.5%; T2D, 3.2% 95% CI, 2.6%-3.9%). The hazard ratio for new-onset diabetes associated with SARS-CoV-2 positivity was 0.44 (95% CI, 0.17-1.13) for T1D and 1.08 (95% CI, 0.74-1.57) for T2D. Conclusions and Relevance: These findings suggest that the incidence and severity of T1D and T2D among South Korean youths increased during the COVID-19 pandemic. The cohort analysis does not support SARS-CoV-2 infection itself as being directly associated with incident diabetes.