Clinical Outcomes for Newly Diagnosed Diabetes Patients in Korea: A National Health Insurance Data

ABSTRACT Aims The early clinical impact of type 2 diabetes is not fully understood due to uncertainties surrounding the timing of disease onset. We assessed clinical outcomes in patients newly diagnosed with type 2 diabetes and without preexisting comorbidities, utilising the Korean National Health Insurance Service database. Materials and Methods We identified patients (20–80 years) newly diagnosed with type 2 diabetes without prior atherosclerotic cardiovascular or kidney disease (eGFR < 60 mL/min/1.73 m 2 , albuminuria, or relevant ICD codes). Age‐ and sex‐matched controls were selected (1:4). Primary outcomes included ischemic/hemorrhagic stroke, myocardial infarction, heart failure, chronic kidney disease (CKD) progression to eGFR < 60 mL/min/1.73 m 2 , renal replacement therapy (RRT), and all‐cause mortality. Results Among 2 164 060 individuals, 432 812 were newly diagnosed with type 2 diabetes. Participants were followed for a median of 5.1 years (IQR 3.3–6.2 years; maximum follow‐up 7.6 years). After adjusting for covariates, the risks in the type 2 diabetes group remained significantly elevated compared to the controls: total composite outcome (hazard ratio, HR [95% confidence interval, CI]: 1.67 [1.64–1.70]), non‐renal composite outcome (1.57 [1.53–1.60]), renal composite outcome (1.86 [1.82–1.90]), and individual outcomes including ischemic stroke (1.73 [1.66–1.80]), hemorrhagic stroke (1.24 [1.14–1.35]), myocardial infarction (1.84 [1.73–1.95]), heart failure (2.17 [2.08–2.27]), CKD progression (1.47 [1.41–1.53]), RRT (4.17 [3.51–4.95]), and all‐cause mortality (1.14 [1.10–1.19]). Conclusions Patients newly diagnosed with type 2 diabetes faced substantially increased risks of cardiovascular, renal complications, and all‐cause mortality, despite preserved baseline kidney function. Proactive risk assessments and preventive strategies are needed to mitigate the long‐term burden of diabetes‐related complications.