Ischemic Stroke in Nonvalvular Atrial Fibrillation at Warfarin Initiation: Assessment via a Large Insurance Database
| Autor: | Wilson Tan, X. Liu, Daniel E. Singer, William Petkun, Jack Mardekian, Melissa Hamilton, Ping G. Tepper |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Male
medicine.medical_specialty Databases Factual Aftercare 030204 cardiovascular system & hematology Brain Ischemia Brain ischemia 03 medical and health sciences 0302 clinical medicine Internal medicine Atrial Fibrillation medicine Humans 030212 general & internal medicine Intensive care medicine Stroke Aged Retrospective Studies Advanced and Specialized Nursing Aged 80 and over Insurance Health business.industry Warfarin Anticoagulants Retrospective cohort study Atrial fibrillation Middle Aged medicine.disease United States Large sample Ischemic stroke Cardiology Female Neurology (clinical) Cardiology and Cardiovascular Medicine business medicine.drug Cohort study |
| Zdroj: | Stroke. 48(6) |
| ISSN: | 1524-4628 |
| Popis: | Background and Purpose— Stroke risk may increase shortly after warfarin initiation in nonvalvular atrial fibrillation patients. Because of the brief period and limited number of events, large samples are needed to study this effect. We compared 30-day rates of ischemic stroke between nonvalvular atrial fibrillation patients initiating warfarin to nonwarfarin comparators using an insurance claims database. Methods— We identified nonvalvular atrial fibrillation patients via 1 inpatient/2 outpatient diagnosis claims from the MarketScan database, January 1, 2009, to December 31, 2010. We studied patients initiating warfarin using prescription claims and 1:1 matched 22 669 initiators to comparators based on age, sex, diagnosis date, and warfarin propensity score. Follow-up began on initiation date; patients were censored at discontinuation/switch of therapy, disenrollment, or end of the study. The median follow-up was 415 days. Cox regression was used to study differences in ischemic stroke risks between warfarin initiators and comparators while controlling for important prognostic factors. Results— Warfarin initiators were generally similar to comparators in clinical features but had higher CHADS 2 scores (1.26 versus 1.19). The first 30-day ischemic stroke rate was higher among warfarin initiators than comparators (1.47%/y (27/1836) versus 0.98%/y (18/1837); P =0.18) but lower subsequently (0.81%/y [134/16 543] versus 1.09%/y [406/37 248]; P =0.002). Multivariable regression confirmed a significant interaction between follow-up and warfarin use with the adjusted hazard ratios (95% confidence intervals) for warfarin/comparator as 1.46 (0.80–2.65) in the first 30 days and 0.70 (0.57–0.85) afterward. Conclusions— Warfarin effect was qualitatively different in the first 30 days after initiation than subsequently. This is consistent with a modest increase in stroke risk occurring briefly after starting warfarin. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|