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Comorbidity associated with atrial fibrillation: a general practice-based study
Insights
Atrial fibrillation significantly increases stroke risk factors, yet contraindications for anticoagulation are common. Approximately 40% of atrial fibrillation patients in primary care have stroke risk factors and no treatment contraindications.
Area of Science:
- Cardiology
- Epidemiology
- Public Health
Background:
- Atrial fibrillation (AF) is a major risk factor for ischemic stroke.
- Anticoagulation (e.g., warfarin) reduces stroke risk in AF patients but has side effects.
- Limited population-based data exists on comorbidities and contraindications for anticoagulation in AF patients.
Purpose of the Study:
- To determine the prevalence of ischemic stroke risk factors in AF patients.
- To identify the prevalence of potential contraindications to anticoagulant therapy in AF patients.
Main Methods:
- A one-year prospective cohort study involving 60 general practices in England and Wales.
- Analysis of a population of 502,493 individuals.
- Calculation of age and sex-specific prevalence rates and relative risks for stroke risk factors and contraindications.
Main Results:
- 1,414 patients (0.3%) had atrial fibrillation.
- Stroke risk factors increased with age in both men and women with AF.
- Contraindications to antithrombotic treatment were present in 5-14% of men and 7-16% of women with AF, increasing with age.
- 40% of AF patients had at least one stroke risk factor and no contraindications to antithrombotic treatment.
Conclusions:
- Atrial fibrillation is linked to a higher prevalence of stroke risk factors.
- Contraindications to antithrombotic treatment are similarly distributed in patients with and without AF.
- A significant proportion (around 40%) of primary care AF patients are at high stroke risk without contraindications for treatment.
Background:
[corrected] Atrial fibrillation is an important risk factor for ischaemic stroke. Anticoagulation treatment with warfarin can substantially reduce the risk of stroke in people with atrial fibrillation but concerns about their side-effects have limited their use in clinical practice. However there has been little population-based research on the comorbidity associated with atrial fibrillation and on the prevalence of potential contraindications to anticoagulantion treatment among these patients.
Aim:
To determine the prevalence of known risk factors for ischaemic stroke and possible contraindications to anticoagulant treatment among patients with atrial fibrillation.
Method:
One-year prospective cohort study in 60 general practices in England and Wales with a total population of 502,493 people. Age and sex specific prevalence rates and relative risks of risk factors for ischaemic stroke and possible contraindications to antithrombotic treatment were calculated.
Results:
The number of patients who had a diagnosis of atrial fibrillation during the year was 1,414 (0.3%) patients. The prevalence of other nsk factors for ischaemic stroke in patients with atrial fibrillation increased with age in men, from 48% (relative risk [RR] = 3.78, 95% confidence interval [95% CI] = 3.23-4.41) at 45 to 64 years to 64% (RR = 2.21, 95% CI = 2.00-2.44) at 75years and over A similar increase of 50% (RR = 4.36, 95% CI = 3.54-5.38) to 60% (RR = 2.07, 95% CI = 1.91-2.23) was seen in women. The percentage of men with atrial fibrillation with at least one contraindication to antithrombotic treatment was 5% at 45 to 64 years and 14% at 75 years and over. Among women with atrial fibrillation, 7% had a contraindication at 45 to 64 years and 16% at 75 years and over. The all-ages relative risk of a contraindication was 1.17 (95% CI = 0.92-1.48) in men and 1.53 (95% CI = 1.28-1.83) in women. Forty per cent (575) of patients with atrial fibrillation had at least one risk factor for ischaemic stroke and no contraindications to antithrombotic treatment.
Conclusion:
Atrial fibrillation is associated with a substantial increase in the prevalence of risk factors for ischaemic stroke. By contrast, potential contraindications for antithrombotic treatment are more evenly distributed among patients with and without atrial fibrillation. Around 40% of patients with atrial fibrillation in primary care are at high risk of stroke and have no contraindicationsfor antithrombotic treatment.