January 1, 2017
View Full PaperAtrial Fibrillation Diagnosis Timing, Ambulatory ECG Monitoring Utilization, and Risk of Recurrent Stroke
Key Result
Late atrial fibrillation diagnosis (>7 days post-stroke) without baseline oral anticoagulation was highly associated with recurrent stroke or TIA (HR 2.0; 95% CI 1.9-2.1).
Study Design
Type
Cohort (n=179,160)
Structured PICO
Does late diagnosis of atrial fibrillation (>7 days post-stroke) without baseline oral anticoagulation increase the risk of recurrent stroke or TIA in patients with an index stroke/TIA?
P
Population
179,160 patients (mean age 67 years, 53.7% female) with an index stroke or TIA event recorded between 2008 and 2011, followed for at least 1 year.
E
Exposure
Late diagnosis of atrial fibrillation (>7 days post-stroke) without baseline oral anticoagulation
C
Comparator
Early AF diagnosis or no AF, and/or presence of baseline oral anticoagulation
O
Outcome
Recurrence of an ischemic stroke or TIAhard clinical
Late diagnosis of atrial fibrillation (>7 days post-stroke) in patients not on baseline oral anticoagulation is associated with a twofold increased risk of recurrent stroke or TIA, highlighting the potential value of early ambulatory ECG monitoring.
Main Result
Hazard Ratio: 2 (95% CI 1.9–2.1)
Abstract
Background— The risk of recurrence after an initial ischemic stroke or transient ischemic attack (TIA) may be impacted by undiagnosed atrial fibrillation (AF). We therefore assessed the impact of AF diagnosis and timing on stroke/TIA recurrence rates in a large real-world sample of patients. Methods and Results— Using commercial claims data (Truven Health Analytics MarketScan), we performed a retrospective cohort study of patients with an index stroke or TIA event recorded in years 2008 through 2011. Patients were characterized by baseline oral anticoagulation, CHADS 2 and CHA 2 DS 2 -VASc scores, AF diagnosis and timing with respect to the index stroke, and presence or absence of post-index ambulatory cardiac monitoring. The primary outcome was the recurrence of an ischemic stroke or TIA. Of 179 160 patients (age 67±16.2 years; 53.7% female), the Kaplan-Meier estimate for stroke/TIA recurrence within 1 year was 10.6%. Not having oral anticoagulation prescribed at baseline and having AF first diagnosed >7 days post-stroke (late AF) was highly associated with recurrent stroke/TIA (hazard ratio, 2.0; 95% confidence interval, 1.9–2.1). Among patients with at least 1 year of follow-up, only 2.6% and 9.7% had ambulatory ECG monitoring in the 7 days and 12 months post-stroke, respectively. Conclusions— AF diagnosed after stroke is an important hallmark of recurrent stroke risk. Increasing the low utilization of cardiac monitoring after stroke could identify undiagnosed AF earlier, leading to appropriate oral anticoagulation treatment and a reduction in stroke/TIA recurrence.