Low Use of Oral Anticoagulant Prescribing for Secondary Stroke Prevention

BACKGROUND: Oral anticoagulation reduces the risk of stroke in atrial fibrillation but is often underused. OBJECTIVES: To identify factors associated with oral anticoagulant prescribing and adherence after stroke or transient ischemic attack (TIA). RESEARCH DESIGN: Retrospective cohort study using linked Ontario Stroke Registry and prescription claims data. SUBJECTS: Consecutive patients with atrial fibrillation and ischemic stroke/TIA admitted to 11 stroke centers in Ontario, Canada between 2003 and 2011. MEASURES: We used modified Poisson regression models to determine predictors of anticoagulant prescribing and multiple logistic regression to determine predictors of 1-year adherence. RESULTS: Of the 5781 patients in the study cohort, 4235 (73%) were prescribed oral anticoagulants at discharge. Older patients were less likely to receive anticoagulation [adjusted relative risk (aRR) for each additional year=0.997; 95% confidence interval (CI), 0.995-0.998], as were those with TIA compared with ischemic stroke (aRR=0.904; 95% CI, 0.865-0.945), prior gastrointestinal bleed (aRR=0.778; 95% CI, 0.693-0.873), dementia (aRR=0.912; 95% CI, 0.856-0.973), and those from a long-term care facility (aRR=0.810; 95% CI, 0.737-0.891). After limiting the sample to those without obvious contraindications to anticoagulation, age, dementia, and long-term care residence continued to be associated with lower prescription of oral anticoagulants. One-year adherence to therapy was similar across most patient groups. CONCLUSIONS: Age, dementia, and long-term care residence are predictors of lower oral anticoagulant use for secondary stroke prevention and represent key target areas for quality improvement initiatives.