Burden of Ischemic Stroke and Intake of Oral Anticoagulants in Patients With Atrial Fibrillation in the UK Primary Care

Study Overview
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Brief Summary
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This study will characterize patients with ischemic stroke, a condition which occurs when a vessel supplying blood to the brain is obstructed, and a subpopulation of patients with irregular and often rapid heart rate (atrial fibrillation) in a UK general population using The Health Improvement Network (THIN) database. The main aim of the study is to estimate in how many patients atrial fibrillation was diagnosed at the moment of stroke and to describe whether these patients received OAC at the time of the stroke. In addition, researchers want to learn about the relative risk of ischemic stroke when such patients did not continue OAC treatment.

Detailed Description
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The primary objectives of the study are to determine the incidence of ischemic stroke in patients registered in the British primary care THIN database and to investigate the OAC exposure, OAC treatment patterns and the relative risk of having an ischemic stroke in relation to OAC treatment for a subgroup of patients, who were diagnosed with non-valvular atrial fibrillation (NVAF) prior to ischemic stroke. Secondary objectives are to determine the number of patients having NVAF diagnosed at the time of ischemic stroke and within 1 and 12 months after ischemic stroke; to describe cardiovascular risk factors for ischemic stroke and pharmacological treatments before and 12 months after ischemic stroke, and to estimate the case-fatality at 1 and 12 months after the occurrence of ischemic stroke.

Official Title
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Burden of Ischemic Stroke and Adherence to Oral Anticoagulants in Atrial Fibrillation in the UK Primary Care

Conditions
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Atrial Fibrillation

Intervention / Treatment
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* Drug: Oral anticoagulant


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Occurrence of an ischemic stroke that lead to hospitalization between 01-Jul-2016 to 30-Jun-2018 and concerned adults registered in the THIN database Subgroup: Patients with diagnosed NVAF prior or at the time of ischemic stroke Exclusion Criteria: None

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 89 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Subjects with ischemic stroke<br>Adult subjects from the UK THIN database who were hospitalized for ischemic stroke between 01-Jul-2016 to 30-Jun-2018 | Drug: Oral anticoagulant<br>* Oral anticoagulants may comprise vitamin K antagonists (VKA) and non-vitamin K antagonist oral antagonists (NOAC).<br>* Other names: Warfarin, acenocoumarol, phenindione, apixaban, dabigatran, edoxaban, rivaroxaban;|
| NVAF patients with ischemic stroke<br>Adult subjects from the UK THIN database who were hospitalized for ischemic stroke between 01-Jul-2016 to 30-Jun-2018 and had a diagnosis of NVAF prior to ischemic stroke (Subgroup) | Drug: Oral anticoagulant<br>* Oral anticoagulants may comprise vitamin K antagonists (VKA) and non-vitamin K antagonist oral antagonists (NOAC).<br>* Other names: Warfarin, acenocoumarol, phenindione, apixaban, dabigatran, edoxaban, rivaroxaban;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of subjects with ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2018 | 
| Incidence of ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2018 | 
| Number of NVAF patients with OAC prescription prior to ischemic stroke | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Duration of OAC treatment before OAC discontinuation for NVAF patients | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Time period from OAC discontinuation to ischemic stroke for NVAF patients | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke after OAC discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke by time since OAC discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke by OAC treatment duration before OAC discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke after VKA discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke by time since VKA discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke by VKA treatment duration before VKA discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke after NOAC discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke by time since NOAC discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 
| Relative risk of NVAF patients for ischemic stroke by NOAC treatment duration before NOAC discontinuation | For NVAF subgroup only | Retrospective analysis of data from 01-Jul-1996 to 30-Jun-2018 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of subjects with first diagnosis of NVAF at time of ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2018 | 
| Number of subjects with first diagnosis of NVAF within 1 month after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jul-2018 | 
| Number of subjects with first diagnosis of NVAF within 12 months after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Prevalence of cardiovascular co-morbidities one year before ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Prevalence of cardiovascular co-morbidities 12 months after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Descriptive analysis of pharmacological treatments of patients with known NVAF diagnosis within 12 months before ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Descriptive analysis of pharmacological treatments of patients with known NVAF diagnosis within 12 months after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Descriptive analysis of pharmacological treatments of patients without known NVAF diagnosis within 12 months before ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Descriptive analysis of pharmacological treatments of patients without known NVAF diagnosis within 12 months after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Case-fatality of patients with known NVAF diagnosis at 1 month after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Case-fatality for patients with known NVAF diagnosis at 12 months after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Case-fatality of patients with unknown NVAF diagnosis at 1 month after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 
| Case-fatality of patients with unknown NVAF diagnosis at 12 months after ischemic stroke |  | Retrospective analysis of data from 01-Jul-2016 to 30-Jun-2019 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ischemic stroke, Non-valvular atrial fibrillation (NVAF), Oral anticoagulants (OAC), Vitamin K antagonists (NKA), Non-vitamin K antagonist oral anticoagulants (NOAC), Discontinuation