Temporal trends in treatment-requiring microvascular complications in young-onset diabetes: A nationwide population-based study

Abstract Aims Microvascular complications contribute to long-term morbidity, but data on young-onset diabetes in Korea are limited. We examined trends and risk factors for treatment-requiring microvascular complications in young-onset diabetes. Methods Data from the Korean Health Insurance Review and Assessment Service (2008–2021) for individuals diagnosed with diabetes before age 30 years were analyzed. Treatment-requiring microvascular complications were defined using diagnostic codes with relevant prescriptions or procedures. Age-standardized incidence and prevalence were estimated using Poisson regression, and risk factors were assessed using time-dependent Cox models. Results We included 6202 and 77,815 individuals with type 1 and type 2 diabetes, respectively. In type 1 diabetes, microvascular complications incidence declined from 32.2 to 12.0 per 1000 persons, while prevalence increased until 2012 and subsequently declined to 71.4 in 2021. In type 2 diabetes, both the incidence (from 31.4 to 12.4) and prevalence (from 72.6 to 43.1) declined steadily. In type 1 diabetes, young adulthood, female sex, and hypertension increased risk; in type 2 diabetes, young adulthood, male sex, low socioeconomic status, and greater comorbidity burden were key predictors. Conclusions Treatment-requiring microvascular complications in young-onset diabetes declined in Korea, but persistent age- and socioeconomic-related disparities highlight the need for equitable prevention and management.