Abstract 16403: Prevalence and Sex Differences in Early-onset Atrial Fibrillation - A Nation-wide Primary Care Study in Norway

Background: Several studies have reported a male:female ratio of 4:1 in lone atrial fibrillation (AF) populations. However, there have been few reports on the young population with AF, and no reports from a primary care setting. Here, we describe prevalence and sex-differences in early-onset AF in a nation-wide register-based study in the primary care sector in Norway. Methods: In Norway, with a population of 5.4 million, healthcare is publicly financed and all general practitioner (GP) claims have been recorded in the Norwegian Control and Payment of Health Reimbursement (KUHR) registry, since 2006. We identified all individuals aged ≥18 and Results: We identified 5563 individuals (28.5% women, age 18-49 years) aged 18-49 in 2019 with AF diagnosed -205 ) with a ratio of 2.5 men:women. In individuals aged 18-29 the prevalence was 0.05% (women 0.04% (164/410367), men 0.07% (292/435001), p=79x10 -8 ). For the age group 30-39 years the prevalence was 0.19% (women 0.12% (408/349639), men 0.27% (985/367730), p=3.9x10 -49 ). For the age group 40-49 years the prevalence was 0.51% (women 0.29% (1013/354815), men 0.72% (2701/373824), p=1.39x10 -155 ). Conclusion: We show that the prevalence of early-onset AF in a nation-wide primary care population is 0.24% and that the sex-difference in prevalence is smaller than previously reported in early-onset and lone AF studies. Our findings underline the need of increased awareness of AF as a disease in the young, and particularly to women in the youngest age-groups.