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

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.

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 m², 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 m², renal replacement therapy (RRT), and all-cause mortality.

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]).

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.