Sex differences in early-onset atrial fibrillation in Norwegian primary care: a retrospective national database...

Individual variation in the need for healthcare constitutes knowledge gaps for young atrial fibrillation (AF) patients. We aimed to estimate the prevalence and primary care burden of early-onset AF in Norway, emphasising sex differences, in a nationwide healthcare database.

We used data from the Norwegian Control and Payment of Health Reimbursement database to identify all Norwegian residents ≥18 years of age registered with a primary care physician (PCP) in 2019, with onset of AF at ≤50 years of age (early-onset AF) in the period 2006-2019. From the accumulated number of early-onset AF cases among current residents, we calculated the prevalence in 2019. The group-level primary care burden was calculated as the total number of annual AF consultations divided by the annual number of AF patients (2014-2018), and individual burden as the mean number of consultations per AF patient per year within the study period. We analysed the distribution of AF consultations between PCP and primary care emergency room (ER) services in total and by sex.

We identified 10 925 Norwegian residents with early-onset AF in 2019 (26.3% women, mean age 48.4 years). The prevalence of early-onset AF was 0.34% (women: 0.19%, men: 0.50%). The early-onset AF population had on average one annual primary care consultation for AF. The individual burden of annual AF consultations varied widely; <1: 66% of women and 54% of men, (1-5]: 25% of women and 36% of men, (5-10]: 6% of women and 8% of men, ≥10: 2% of women and 2% of men. A higher proportion of men (71%) than women (38%) attended both PCP and ER services due to AF.

The study confirmed a low prevalence of early-onset AF, with substantial sex differences and individual variation in primary healthcare needs. Our results signal a need for a higher resolution with regard to age groups in future research on burden and sex differences in early-onset AF.