Swedish Atrial Fibrillation Cohort Research Articles

Considerations when choosing an appropriate bleeding risk assessment tool for patients with atrial fibrillation

Considerations when choosing an appropriate bleeding risk assessment tool for patients with atrial fibrillation

Efficacy and safety of non-vitamin K antagonist oral anticoagulants compared with warfarin in patients with atrial fibrillation

AimsNon-vitamin K antagonist oral anticoagulants (NOACs) were in pivotal randomised controlled trials at least non-inferior to warfarin for stroke prevention in atrial fibrillation, but time in therapeutic range (TTR) for...

Abstract 18538: The ATRIA Stroke Risk Score Predicts Ischemic Stroke Better than CHADS2 and CHA2DS2-VASc in a large Swedish Cohort of Patients with Atrial Fibrillation

Introduction: Atrial fibrillation (AF) is a major risk factor for acute ischemic stroke (AIS). Anticoagulation therapy (OAC) effectively prevents AIS, but increases bleeding risk. There is a need for better AIS risk prediction to optimize the anticoagulation decision in AF. The ATRIA stroke risk score (ATRIA) (table) was superior to CHADS2 and CHA2DS2-VASc in two large California community AF cohorts. We now report the performance of the 3 scores in a very large Swedish AF cohort. Methods: The cohort consisted of all Swedish patients hospitalized with a diagnosis of AF from July 1, 2005 to December 31, 2008. Predictor variables and the outcome, AIS, were obtained from inpatient ICD-10 codes. Warfarin use was determined from National Pharmacy Database. Risk scores were assessed via c-index (C) and net reclassification index (NRI). Results: The cohort included 158,370 AF patients off warfarin who contributed 340,332 person-years of follow-up, and 11,823 incident AIS, for an overall AIS rate of 3.47%/yr, higher than the 2%/yr seen in the California cohorts. Using the entire point score, ATRIA had a good C of 0.712 (0.708-0.716), significantly better than CHADS2, 0.694 (0.689-0.698), or CHA2DS2-VASc, 0.697 (0.693-0.702). Using published cut-points for Low/Moderate/High AIS risk, C deteriorated for all scores but ATRIA and CHADS2 were superior to CHA2DS2-VASc. NRI favored ATRIA; 0.16 (0.15-0.18) versus CHADS2; 0.22 (0.21-0.24) versus CHA2DS2-VASc. However, NRI decreased to near-zero when cut-points were altered to better fit the cohort’s stroke rates. Conclusion: Findings in this large Swedish AF cohort validate those in the California AF cohorts, with the ATRIA score predicting stroke risk better than CHADS2 or CHA2DS2-VASc. However, relative performance of the categorical scores varied by population stroke risk. Knowledge about this population risk may be needed to optimize cut-points on the multipoint scores to achieve better net clinical benefit from OAC.