Introduction and objectives: The aims of this study were to determine the prevalence of atrial fibrillation in individuals aged 60 years or more in Spain using a random sample of the population and to identify associated factors.
Methods: An analysis of the PREV-ICTUS study, a randomized cross-sectional population-based study of individuals aged 60 years or more, was carried out. Data on demographic variables, cardiovascular risk factors, and cardiovascular disease were obtained from medical records. The diagnosis of atrial fibrillation was based on the patient's medical history and an electrocardiogram performed during the study.
Results: In the 7108 individuals studied (mean age 71.9 [7.1] years, 53.6% female), the prevalence of atrial fibrillation was 8.5% (95% confidence interval [CI] 7.9-9.2%). It was higher in males (9.3% vs 7.9% in females; P=.036) and increased from 4.2% in individuals aged 60-64 years to 16.5% in those aged 85 years or more (chi-squared test for linear trend, P< .001). Multivariate analysis showed that existing cardiovascular disease, hypertension, age, and left ventricular hypertrophy had the strongest associations with atrial fibrillation. Although there was a strong relationship between hypertension and atrial fibrillation (odds ratio 2.53, 95% CI, 1.60-4.01), no association was found between poor blood pressure control and atrial fibrillation. A weak association with diabetes mellitus was found only when arterial pressure was included in the model, but not when a diagnosis of hypertension was included.
Conclusions: In this cross-sectional population-based study of elderly individuals, the prevalence of atrial fibrillation was 8.5%, and was strongly associated with existing cardiovascular disease, hypertension, age and left ventricular hypertrophy.