Progression of stroke risk in patients aged <65 years diagnosed with atrial fibrillation: a cohort study in general practice

Background As a result of new technologies, atrial fibrillation (AF) is more likely to be diagnosed in people aged <65 years. Aim To investigate the risk of someone diagnosed with AF aged <65 years developing an indication for anticoagulation before they reach 65 years. Design and setting Population-based cohort study of patients from English practices using the Clinical Practice Research Datalink, a primary care database of electronic medical records. Method The study included patients aged <65 years newly diagnosed with AF. The CHA(2)DS(2)-VASc score was derived at time of diagnosis based on patients' medical records. Patients not eligible for anticoagulation were followed up until they became eligible or turned 65 years old. The primary outcome of interest was development of a risk factor for stroke in AF. Results Among 18 178 patients aged <65 years diagnosed with AF, 9188 (50.5%) were eligible for anticoagulation at the time of diagnosis. Among the 8990 patients not eligible for anticoagulation, 1688 (18.8%) developed a risk factor during follow-up before reaching 65 years of age or leaving the cohort for other reasons, at a rate of 6.1 per 100 patient-years. Hypertension and heart failure were the most common risk factors to occur, with rates of 2.65 (95% CI = 2.47 to 2.84) and 1.58 (95% CI = 1.45 to 1.72) per 100 patient-years, respectively. The rate of new diabetes was 0.95 (95% CI = 0.85 to 1.06) per 100 patient-years. Conclusion People aged <65 years with AF are at higher risk of developing hypertension, heart failure, and diabetes than the general population, so may warrant regular review to identify new occurrence of such risk factors.