Vivek Rai, MD

Melgaard L, Rasmussen LH, Skjøth F, Lip GYH, and Bjerregaard Larsen TB. Age Dependence of Risk Factors for Stroke and Death in Young Patients With Atrial Fibrillation: A Nationwide Study. Stroke. 2014

Atrial fibrillation (AF) is the most common arrhythmia and prevalence of AF of increases with age. Patients with AF are at high risk for stroke and thromboembolism but the risk is also dependent on presence of various stroke risk factors in the individual patient. CHADS2 score is the most commonly used risk stratification score and has been refined to produce CHA2DS2-VASc score. The importance of CHA2DS2-VASc score lies in its ability to identify “truly low-risk” patient who may not need anti-thrombotic treatment. The risk stratification scores have primarily been evaluated in patients >65 years of age and there is little data, if any, about utility of these scores in younger age group. 

Melgaard et al analyzed the data of patients aged 30 to 65 years diagnosed with AF between 2000 and 2011 utilizing The Danish National Patient Registry. The authors identified 73799 non-valvular AF, of which about half (51.2%) were aged <65 years. The overall incidence of stroke per year for 1 year (5 years) follow-up was 1.2% (0.6%), 3.5% (1.6%), and 5.6% (2.8%) respectively, for the age groups of 30-50, 50-65, and 65-75. A higher CHA2DS2-VASc score was associated with higher mortality. Prior stroke, heart failure, vascular disease, diabetes, and hypertension remained independent predictors of stroke and death.

Of note, the risk stratification score used in the analysis is modified to exclude scoring for age and sex and it was not possible to determine the subtype of stroke. Also, this is a retrospective analysis of data obtained using diagnostic codes which may have resulted in over or underestimation of risk. Nevertheless, the authors have reliably shown that CHA2DS2-VASc score is a valid tool for risk stratification of younger patients as well. The study will not change my clinical practice but reinforces the, so far presumed, validity of CHA2DS2-VASc score in identifying young patients who are at very low risk of stroke due to AF and may not need anti-thrombotic treatment.