GARFIELD-AF Risk Calculator

• Unlike conventional risk scores, it simultaneously provides the risk of ischaemic stroke, major bleeding as well as mortality.
• Uniquely, the calculator helps clinicians to judge whether the benefits of anticoagulation outweigh the risks in patients with a range of baseline risk factors.
• It includes factors beyond those included in conventional risk scores to improve its predictive power and is based on data from a global community. The calculator uses routinely collected clinical parameters that have been shown to have predictive power for adverse events.
• The GARFIELD-AF risk tool was validated in an external population (ORBIT-AF registry). The model exerted good calibration and discrimination.

To use the GARFIELD-AF risk tool for any patient with a new diagnosis of AF:
1. Enter the patient data by selecting from the ranges given or by using the yes/no toggle switches. When finished, click "Calculate" to obtain risk of event probabilities.
2. The risk plot allows you to compare the risk of mortality, ischaemic stroke or systemic embolism and major bleeding including haemorrhagic stroke over time. You can filter the results by anticoagulant treatment using the boxes in the upper right corner.
3. The table at the bottom provides the estimated probabilities for three possible treatment decisions: no oral anticoagulation (no OAC), vitamin K antagonist (VKA), or non-vitamin K antagonist oral anticoagulant (NOAC). You may select the estimates to refer to a specific time point after AF diagnosis using the time bar to the right of the table.
4. If you would like to see how a different input impacts your results, just click “Back to Questions”, edit the values you wish to modify and click “Calculate”.

The risk calculator was derived from GARFIELD-AF, the largest prospective, observational, multicentre global registry of adult patients with newly diagnosed AF. Data were gathered between March 2010 and August 2016 from over 1000 centres in 35 countries. Adult patients who had been recently diagnosed with AF (not related to mechanical valves or severe valve disease, i.e. non-valvular) and had at least one risk factor for stroke were enrolled in the registry. Patients for whom follow-up was not available were excluded.

The work on the calculator was led by the Thrombosis Research Institute (TRI) in London, UK, which sponsors the GARFIELD-AF registry and supported by an unrestricted research grant from Bayer AG, Berlin, Germany, to TRI, which sponsors the GARFIELD-AF registry. Karen Pieper and Saverio Virdone from TRI analysed the GARFIELD-AF database and created the algorithms. Clinical guidance was provided by the GARFIELD-AF Steering Committee, led by Professor Keith Fox, University of Edinburgh, UK.

References
[1] Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation. Fox KAA, Lucas JE, Pieper KS, et al; GARFIELD-AF Investigators. BMJ Open. 2017 Dec 21;7(12):e017157.