Patients with atrial fibrillation have an increased risk of thromboembolic complications and mortality.1 To estimate the impact of prophylactic treatment in the general population it is important to know the prevalence of atrial fibrillation in primary care. Epidemiological surveys have reported different prevalence rates, probably because of differences in study populations and methods.1 2 Generally, the risk of stroke in patients with atrial fibrillation may be significantly reduced, but treatment advice for individual patients depends on comorbidity and its consequences.3 Therefore, it is important to identify features that influence prognosis in such patients. The aim of this study was to estimate the prevalence of atrial fibrillation and comorbidities among elderly patients in general practice. Prevalence and comorbidity were studied in patients …