Long Term follow-up of a randomised controlled trial of warfarin versus aspirin for stroke prevention in the management of atrial fibrillation in an elderly (aged > 75) primary care population.
Atrial fibrillation (AF) is an important cause of morbidity and mortality. People with AF have an increased risk of death from cardiovascular diseases including stroke. The prevalence of both stroke and AF increase with age.
Previous research found anticoagulants such as warfarin were more effective than aspirin at preventing stroke, but this benefit is at the cost of higher risk of major bleeding. However, concerns were expressed over the applicability of this evidence to elderly patients with AF, particularly in primary care settings. The BAFTA study aimed to address these concerns. The BAFTA study was a randomised controlled trial of warfarin versus aspirin for stroke prevention in atrial fibrillation in people aged 75 and over, recruited in primary care.
The BAFTA study found evidence that warfarin was superior to aspirin in reducing the incidence of stroke in elderly AF patients. However despite this finding, there remain gaps in our knowledge of the effectiveness of anticoagulation in people aged over 75 in AF. It is particularly important to investigate this age group because the majority AF patients are over 75. Since the BAFTA study, a number of new anticoagulants (apixaban, dabigatran and rivaroxaban) have been developed and evaluated. These appear to be at least as affective as warfarin but cost effectiveness remains a significant issue.
Therefore it is important to precisely quantify the ‘real world’ benefits of warfarin in order to better understand the potential role of these new anticoagulation agents.
As BAFTA was the largest primary care based randomised controlled trial performed in AF in this age group, this follow up will provide crucial data on the feasibility of long term use of anticoagulation in over 75s, and answer important clinical effectiveness questions.
Aim of study
This study aims to extend the follow up of study patients from an average 2.7 years to approximately 9 years. The primary aim is:
- To determine the longer term effects of anticoagulation (as compared to antiplatelet or no therapy) in terms of overall mortality and risk of stroke and cardiovascular events.
Secondary aims are:
- To report the longer term adherence to anticoagulation therapy in this age group
- To report the incidence of haemorrhage in people taking anticoagulants as compared to antiplatelet agents or no therapy
- To compare the survival of people in AF who did and did not take part in BAFTA and whether the observed association of anticoagulation with improved survival in the non-randomised cohort persisted over the long term.
- Validation of the HAS-BLED bleeding risk score and CHA2DS2VASc stroke risk stratification tool
The 260 General practices throughout England and Wales who enrolled patients to the Birmingham Atrial Fibrillation Treatment of the Aged (BAFTA) study, either for entry to the full trial or for access to medical records only.
Patients aged 75 and over with a diagnosis of atrial fibrillation and who participated in the original BAFTA study.