How many more people will we need to anticoagulate using CHA2DS2VASc? A real-life study in British primary care

Managing stroke risk in people with atrial fibrillation (AF) is critical. The introduction of the CHA₂DS₂VASc score has lowered the threshold for consideration of anticoagulation to prevent stroke in AF. This means potentially extra work for clinicians in assessing AF patients, and an extra cost to the NHS from more medication and monitoring. This study aims to quantify the increase in the numbers of people requiring anticoagulation with the newer risk assessment score. Method: The GRASP-AF tool was used to quantify the number of people categorised as high risk, using the CHA₂DS₂VASc score compared with the standard CHADS₂ score. Population: An inner-city population from nine general practices within a single Clinical Commissioning Group (CCG), covering a population of 42,274 patients. Results: A total of 395 patients were found to have AF. In this study, 64% were categorised as high risk using CHADS₂ compared with 87% on CHA₂DS₂VASc. This represents an increase of 35% in the numbers of people classed at high risk of stroke and needing to be considered for anticoagulation. Conclusion: There are significant extra costs to implementing the CHA₂DS₂VASc score, both in drug costs and extra work for primary care, which need to be managed within the local health system. The greatest benefit will be at an individual level. Some people who would have had a stroke will be spared that experience. Who those individuals are, we will never know.