Secondary Prevention Adherence and Clinical Outcomes in Diabetic Patients After Acute Coronary Syndrome

Background Patients with coronary artery disease (CAD) and Type 2 diabetes mellitus (DM) represent a high‐risk population for recurrent cardiovascular events following acute coronary syndrome (ACS). Despite evidence‐based guidelines, adherence to secondary prevention strategies remains suboptimal. This study evaluated the impact of comprehensive guideline‐based secondary prevention adherence, including contemporary heart failure therapies, on major adverse cardiovascular events (MACE) in patients with CAD and DM post‐ACS, extending prior work that examined rehospitalization and all‐cause mortality outcomes. Methods This retrospective cohort study included 712 patients with confirmed CAD and Type 2 DM who presented with ACS between September 2019 and December 2022. Adherence to ten evidence‐based secondary prevention measures was assessed before the index ACS event and at 3‐year follow‐up, including antiplatelet therapy, high‐intensity statins, blood pressure control, ACE inhibitors/ARBs, beta‐blockers, SGLT‐2 inhibitors, mineralocorticoid receptor antagonists (MRA), angiotensin receptor‐neprilysin inhibitors (ARNI), lifestyle modifications, and other guideline‐recommended interventions. Patients were stratified into low (≤ 3), moderate (3–6), and high (> 6) adherence groups. Primary outcomes were MACE, including cardiovascular death, nonfatal myocardial infarction, stroke, and urgent revascularization over 3 years. Results Mean patient age was 61.7 ± 12.1 years, with 58.4% male participants. Dramatic improvements in adherence occurred post‐ACS: high adherence increased from 12.6% to 62.1% ( p < 0.001). Significant increases were observed in statin therapy (22.5%–84.7%), antiplatelet therapy (58.3%–91.2%), and blood pressure control (33.6%–87.4%). Cox regression analysis identified better adherence scores as an independent protective factor (HR 0.798, 95% CI 0.686–0.929, p = 0.004). Kaplan–Meier analysis demonstrated superior event‐free survival in high adherence patients (88% vs. 70% in the low adherence group, p < 0.001). Statin therapy showed the strongest protective effect (HR 0.512, 95% CI 0.386–0.679, p < 0.001). Conclusion ACS events significantly improve adherence to secondary prevention strategies in CAD patients with diabetes, with high adherence associated with substantial reductions in MACE and improved long‐term survival.