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38DE. Congestive heart failure, hypertension, age, diabetes, stroke 2 risk score - Score of 1
8B6P. Clopidogrel prophylaxis (v23)
Atrial fibrillation is the most common sustained cardiac arrhythmia and if left untreated is a significant risk factor for stroke and other morbidities.
There is evidence that stroke risk can be substantially reduced by warfarin (approximately 66 per cent risk reduction) and less so by aspirin (approximately 22 per cent risk reduction).
To help clinicians decide which management path to choose, several tools have been developed to estimate the risk of stroke on the basis of clinical factors. The scoring system recommended for QOF is CHADS2, which is validated and particularly suitable for identifying high-risk AF patients, while also being relatively simple to use. The CHADS2 system is based on the AF Investigators I Study (AFI1) and Stroke Prevention in AF I Study (SPAF1) risk criteria
The revised CHADS2 system scores one point, up to a maximum of six, for each of the following risk factors (except previous stroke or TIA, which scores double, hence the 2)
1. C - Congestive HF (One Point)
2. H - Hypertension (One Point)
3. A - Age 75 or Over (One Point)
4. D - Diabetes Mellitus (One Point)
5. S2 - Previous strke or TIA (Two Points)
A score of zero is classified as low risk, one is moderate risk and two or more is high risk.
Evidence from the Birmingham Atrial Fibrillation Treatment of the Aged (BAFTA) and Atrial fibrillation Clopidogrel Trial with Irbesartan for prevention of Vascular Events (ACTIVE-W) studies suggests that not only is warfarin more effective than aspirin, but that it is not as unsafe (in terms of risk of serious haemorrhage) as previously thought. For example, in the BAFTA trial, the relative risk (RR) for stroke for patients treated with anti-coagulation versus aspirin was 0·46 (95% confidence interval [CI] 0·26 to 0·79). The same study showed no significant difference in the rate of haemorrhage between the warfarin and aspirin arms of the study (RR 0·88, 95% CI 0·46 to 1·63), which suggests a shift in the balance between the risks and benefits of warfarin compared with aspirin. However, to date no meta-analysis has been identified combining the results of studies comparing the two treatments for the outcome of haemorrhage.
Anti-coagulation would not necessarily be indicated if the episode of atrial fibrillation was an isolated event that was not expected to re-occur (for example, one-off atrial fibrillation with a self-limiting cause).
This indicator uses the CHADS2 risk stratification scoring system to inform treatment options.The use of a risk stratification scoring system is in line with European Society of Cardiology (ESC) (2010) guidance that states that recommendations for therapy should be based on the presence (or absence) of risk factors for stroke and thromboembolism.
Where the CHADS2 score is 0 (low risk), then the patient can be offered treatment with aspirin. Where the CHADS2 score is 1 (moderate risk) then either aspirin or anti-coagulants can be offered.
See indicator wording for requirement criteria.
The Business Rules will look for the latest CHADS2 score in the patient record and if the score is 1, the patient is eligible for inclusion in the denominator.
No authors listed (1994) Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation: analysis of pooled data from five randomized clinical trials. Archives of Internal Medicine 154: 1449-57
Mant J, Hobbs FD, Fletcher K et al. (2007) Warfarin versus aspirin for stroke prevention in an elderly community population with atrial fibrillation (the Birmingham Atrial Fibrillation Treatment of the Aged Study, BAFTA): a randomised controlled trail. Lancet 370: 493-503
Healey JS, Hart RG, Pogue J et al. (2008) Risks and benefits of oral anticoagulation compared with clopidogrel plus aspirin in patients with atrial fibrillation according to stroke risk: the Atrial fibrillation Clopidogrel Trial with Irbesartan for prevention of Vascular Events (ACTIVE-W). Stroke 39: 1482-6
Guidelines for the management of atrial fibrillation The Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC) (2010). European Heart Journal 31: 2369-429. Available from www.escardio.org/guidelines-surveys/esc-guidelines/GuidelinesDocuments/guidelines-afib-FT.pdf
Prepared By Jean Keenan