Medication adherence to secondary prevention after ischemic cerebrovascular disease: a real-world outcomes analysis

Introduction: Ischemic cerebrovascular disease (ICD) poses a major global burden. Non-adherence to medical secondary prevention leads to recurrent events and disability. Real-world data on adherence to preventive medications is scarce. The objective here is to determine adherence to secondary prevention of ICD and its effect on clinical outcomes. Methods: This retrospective observational study was based on claims data from a large Swiss health insurance. We studied patients aged 18 years or older, who were hospitalized for ICD between 2017 and 2021. Patients' one-year medication adherence was determined by the medication possession ratio (MPR, high adherence defined as MRP ≥ 0.80). Outcome variables were all-cause death, recurrent stroke, admission to nursing home, and major adverse cardiovascular events. Results: A total of 9,911 patients with ischemic stroke or TIA were included in the analysis. Lipid-lowering drugs (LLD) had the largest proportion of high adherence users (63.2%), followed by antihypertensives (55.4%) and antiplatelets (50.0%). Female patients were 37% less likely to adhere to LLD therapy than men, highlighting a significant gender gap. Users with high adherence to LLD had a significantly reduced risk for all-cause death (HR 0.86, 95% CI 0.79, 0.94); Direct oral anticoagulants (HR 0.88, 95% CI 0.78, 1.00) and antihypertensives (HR 0.93, 95% CI 0.85, 1.01) showed a trend towards a protective effect. Discussion: A remarkable proportion of patients were non-users or had low adherence to medical secondary prevention. Since insufficient secondary prevention may lead to an increased all-cause death rate, efforts are needed to raise awareness among healthcare professionals and improve patient compliance.