Clinical Outcomes and Medication Adherence in Acute Coronary Syndrome Patients With and Without Type 2 Diabetes Mellitus: A Longitudinal Analysis 2006-2011

Abstract

BACKGROUND: The presence of type 2 diabetes mellitus magnifies the risks associated with acute coronary syndrome (ACS), increasing the risk of recurrent cardiovascular events (CVEs) and doubling the risk of death. Managing cardiovascular risk factors has little effect on lowering the mortality risk in patients with type 2 diabetes. OBJECTIVE: To evaluate the relationship between type 2 diabetes mellitus and subsequent CVEs and medication adherence following ACS hospitalization. METHODS: Patients with ACS were identified using ICD-9-CM codes for acute myocardial infarction or unstable angina. The risk of subsequent CVEs was assessed at 1 and 3 years after the index ACS event based on type 2 diabetes status, adjusting for baseline demographic characteristics, comorbidities, medication use, and index ACS characteristics. RESULTS: Of 140,903 patients with ACS (mean age 66.8 years, 58.6% male), 27.4% had type 2 diabetes. During follow-up, 22.0% had subsequent CVEs (26.2% type 2 diabetes, 19.0% nondiabetes). After adjusting for other covariates, type 2 diabetes was associated with increased risk of subsequent CVEs by 9.7% at 1 year and 10.2% at 3 years (both P < 0.001). Most patients were not revascularized at first recurrence after index ACS discharge (79.2% type 2 diabetes, 77.5% nondiabetes). Patients with type 2 diabetes had statistically significant higher adherence rates for antiplatelet agents at 1 year and antihypertensives at 1 and 3 years versus nondiabetes patients. Persistence was higher in the type 2 diabetes group for antihypertensives and in the nondiabetes group for antiplatelet agents and statins. CONCLUSIONS: This analysis demonstrates that patients with type 2 diabetes have a higher risk of subsequent CVEs following an initial event versus those without diabetes, despite evidence of higher treatment persistence for certain medications. Adherence rates remained suboptimal, suggesting a continuing need for patient education.