Does physical activity reduce cardiovascular risk associated with knee osteoarthritis in type 2 diabetes? A nationwide cohort study

Background/Aims: Knee osteoarthritis (OA), type 2 diabetes mellitus (T2DM), and cardiovascular disease (CVD) share overlapping mechanisms but are often managed independently. We evaluated whether knee OA increases CVD risk in Korean T2DM patients and whether physical activity (PA) modifies this risk.Methods: We conducted a nationwide cohort study using data from the Korean National Health Insurance Service. A total of 1,068,215 adults with T2DM screened between 2009–2012 were followed until CVD events or end of follow-up in 2018. Knee OA was identified by ICD-10 codes and radiographic imaging. PA was classified as none, intermittent (≥ 1 session/week), or regular (≥ 3 sessions/week). Cox models were used to estimate hazard ratios (HRs) for myocardial infarction (MI), stroke, heart failure (HF), and cardiovascular mortality, adjusting for demographics, BMI, eGFR, lifestyle factors, hypertension, dyslipidemia, insulin use, and antidiabetic medication.Results: Knee OA independently increased risks for overall CVD (HR 1.13, 95% CI 1.11–1.16), MI (1.07, 1.02–1.13), stroke (1.14, 1.10–1.18), and HF (1.13, 1.09–1.17). Cardiovascular mortality was not significantly increased (HR 0.99, 95% CI 0.92–1.07). The association was stronger among non-insulin users and patients with diabetes duration < 5 years. Even intermittent PA significantly reduced cardiovascular mortality among OA patients (HR 0.69, 95% CI 0.61–0.78).Conclusions: Knee OA substantially elevates CVD risk in Korean T2DM patients, particularly early in disease progression. Even modest PA confers meaningful cardiovascular protection. Early cardiovascular assessment and tailored PA recommendations are essential for comprehensive diabetes management in patients with OA.