Background It is unclear whether the incidence of non‐valvular atrial fibrillation ( NVAF ) has been increasing over time. We aimed to provide contemporary estimates of the incidence and case‐fatality of NVAF in a well‐defined population. Methods and Results We used the computerized databases of the Régie de l'assurance maladie du Québec ( RAMQ ), responsible for administering the universal health care services for all its residents, to identify a population‐based cohort of 243 800 patients with an incident diagnosis of NVAF during 2000–2009. The incidence rate of NVAF , age‐ and sex‐standardized to the 2004 population of Québec, was 32.4 (95% confidence interval, 32.3 to 32.5) per 10 000 per year. There was no evidence of an increasing incidence of NVAF during the 10‐year study period. The incidence rate was higher in men compared with women (age‐adjusted incidence rate ratio 1.51; 95% CI 1.50 to 1.52). The 30‐day case‐fatality was 9.2% (95% CI 9.0 to 9.3), higher for men (10.0%; 95% CI 9.8 to 10.1) than women (8.5; 95% CI 8.3 to 8.6), and increasing with age, ranging from around 1% for cases aged Conclusion Current incidence estimates illustrate the significant burden of NVAF . Mortality remains particularly high around the time of diagnosis, and case‐fatality increases with age, being systematically higher in men than women.
