Associations With Anticoagulation: Stroke Survivors With AF
Associations With Anticoagulation: Stroke Survivors With AF
Objective: To describe vitamin K antagonist (VKA) anticoagulation prescribing patterns in stroke survivors with atrial fibrillation (AF), with particular emphasis on sociodemographic associations with VKA prescription.
Methods: We conducted a cross-sectional analysis of city-wide Glasgow primary care data held as part of the Local Enhanced Services (LES) for the year 2010. We collated clinical and sociodemographic data of community-dwelling ischaemic stroke survivors with AF, including risk factors; comorbidity; socioeconomic status and prescribing. We described stroke risk and bleeding risk using recommended stratification tools (CHA2DS2-VASC and HAS-BLED). Univariate and multivariate associations with anticoagulant prescription were described by ORs and corresponding 95% CI.
Results: We identified 3429 community-dwelling, ischaemic stroke survivors with AF; median age 78 (IQR 72–84); 1699 (49%) male. Median CHA2DS2-VASC score was 5 (IQR 4–6). VKA was prescribed in 1165 (34%). On univariate analysis, higher CHA2DS2-VASC was associated with fewer VKA prescriptions (OR 0.90, 95% CI 0.45 to 0.95). On multivariate analysis, older age (OR 0.97, 95% CI 0.96 to 0.98) and higher deprivation scores (OR 0.59, 95% CI 0.57 to 0.76) were independently associated with non-prescription of VKA.
Conclusions: Anticoagulation was underused in this high-risk population, and those at highest risk were less likely to be treated. Strategies need to be developed to improve prescription of anticoagulation treatment.
Atrial fibrillation (AF) is a common and treatable cause of ischaemic stroke. With an aging population and better survival of patients with chronic cardiac diseases, prevalence of AF is expected to increase substantially.
We have effective treatments to prevent AF-related stroke. Oral anticoagulant drugs, traditionally vitamin K antagonists (VKA) such as warfarin, reduce the annual risk of recurrent AF with a typical annual risk reduction of 2.7%, higher in the context of secondary prevention poststroke. International guidelines and local prescribing protocols advocate consideration of anticoagulation for subjects with AF informed by stroke and bleeding risk-stratification tools. Examples include the CHADS2 and CHA2DS2-VASC stroke risk scores and the HAS-BLED bleeding risk score. The most important risk factor for future AF-related stroke is history of previous stroke event, and so all scoring systems recommend anticoagulation in ischaemic stroke survivors with AF.
Glasgow data suggest potential underuse of evidence-based secondary prevention for cardiovascular diseases, although rates of anticoagulation in stroke survivors have not previously been described at city level. Prescribing data in cohorts of stroke survivors can help describe patterns of anticoagulation, which may in turn be used to explain and target potential areas of prescribing inequality. While there have been several studies describing patterns of prescribing in cardiovascular disease, there are limited numbers of studies looking at clinical and sociodemographic predictors or associations with prescribing. Highly cited studies of VKA prescribing inequality are now over a decade old. Recognising the recent increased emphasis on treatment of AF in primary care, a contemporary analysis of prescribing in primary care is warranted.
The 'substrate' for such analyses should be a representative sample of community-dwelling stroke survivors, well phenotyped for sociodemographic, clinical and prescribing data. In Glasgow, UK, we have a city-wide database that is suited to analyses of prescribing patterns, offering central data storage of annual comprehensive, individual patient-level assessment of stroke survivors—the NHS Greater Glasgow and Clyde Local Enhanced Service (stroke) registry.
We sought to describe primary care anticoagulant prescribing in stroke survivors using Local Enhanced Services (LES) data. Primary outcomes of interest were association between anticoagulant prescribing and clinical or demographic factors, particularly the association between anticoagulant prescribing and common AF/bleeding risk stratification tools and associations with socioeconomic deprivation.
Abstract and Introduction
Abstract
Objective: To describe vitamin K antagonist (VKA) anticoagulation prescribing patterns in stroke survivors with atrial fibrillation (AF), with particular emphasis on sociodemographic associations with VKA prescription.
Methods: We conducted a cross-sectional analysis of city-wide Glasgow primary care data held as part of the Local Enhanced Services (LES) for the year 2010. We collated clinical and sociodemographic data of community-dwelling ischaemic stroke survivors with AF, including risk factors; comorbidity; socioeconomic status and prescribing. We described stroke risk and bleeding risk using recommended stratification tools (CHA2DS2-VASC and HAS-BLED). Univariate and multivariate associations with anticoagulant prescription were described by ORs and corresponding 95% CI.
Results: We identified 3429 community-dwelling, ischaemic stroke survivors with AF; median age 78 (IQR 72–84); 1699 (49%) male. Median CHA2DS2-VASC score was 5 (IQR 4–6). VKA was prescribed in 1165 (34%). On univariate analysis, higher CHA2DS2-VASC was associated with fewer VKA prescriptions (OR 0.90, 95% CI 0.45 to 0.95). On multivariate analysis, older age (OR 0.97, 95% CI 0.96 to 0.98) and higher deprivation scores (OR 0.59, 95% CI 0.57 to 0.76) were independently associated with non-prescription of VKA.
Conclusions: Anticoagulation was underused in this high-risk population, and those at highest risk were less likely to be treated. Strategies need to be developed to improve prescription of anticoagulation treatment.
Introduction
Atrial fibrillation (AF) is a common and treatable cause of ischaemic stroke. With an aging population and better survival of patients with chronic cardiac diseases, prevalence of AF is expected to increase substantially.
We have effective treatments to prevent AF-related stroke. Oral anticoagulant drugs, traditionally vitamin K antagonists (VKA) such as warfarin, reduce the annual risk of recurrent AF with a typical annual risk reduction of 2.7%, higher in the context of secondary prevention poststroke. International guidelines and local prescribing protocols advocate consideration of anticoagulation for subjects with AF informed by stroke and bleeding risk-stratification tools. Examples include the CHADS2 and CHA2DS2-VASC stroke risk scores and the HAS-BLED bleeding risk score. The most important risk factor for future AF-related stroke is history of previous stroke event, and so all scoring systems recommend anticoagulation in ischaemic stroke survivors with AF.
Glasgow data suggest potential underuse of evidence-based secondary prevention for cardiovascular diseases, although rates of anticoagulation in stroke survivors have not previously been described at city level. Prescribing data in cohorts of stroke survivors can help describe patterns of anticoagulation, which may in turn be used to explain and target potential areas of prescribing inequality. While there have been several studies describing patterns of prescribing in cardiovascular disease, there are limited numbers of studies looking at clinical and sociodemographic predictors or associations with prescribing. Highly cited studies of VKA prescribing inequality are now over a decade old. Recognising the recent increased emphasis on treatment of AF in primary care, a contemporary analysis of prescribing in primary care is warranted.
The 'substrate' for such analyses should be a representative sample of community-dwelling stroke survivors, well phenotyped for sociodemographic, clinical and prescribing data. In Glasgow, UK, we have a city-wide database that is suited to analyses of prescribing patterns, offering central data storage of annual comprehensive, individual patient-level assessment of stroke survivors—the NHS Greater Glasgow and Clyde Local Enhanced Service (stroke) registry.
We sought to describe primary care anticoagulant prescribing in stroke survivors using Local Enhanced Services (LES) data. Primary outcomes of interest were association between anticoagulant prescribing and clinical or demographic factors, particularly the association between anticoagulant prescribing and common AF/bleeding risk stratification tools and associations with socioeconomic deprivation.
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