Trends in incidence and mortality in the hospital diagnosis of atrial fibrillation or flutter in Denmark, 1980-1999.

Background: The incidence of diagnosed atrial fibrillation is increasing in the USA, England, Wales, Scotland and Denmark, and the mortality rate in patients with diagnosed atrial fibrillation has been reported to be declining in Scotland and Denmark. We undertook this study to examine recent trends in incidence and mortality in subjects with a hospital diagnosis of atrial fibrillation or flutter in Denmark from 1980 to 1999 by sex, 10-year age group and conditions of comorbidity.

Methods: We identified all individuals, aged 40-89 years, with an incident hospital diagnosis of atrial fibrillation or flutter in the Danish National Registry of Patients, and subjects were followed in the Danish Civil Registration System. We used multivariate Cox proportional hazard models to estimate trends in mortality.

Results: Atrial fibrillation or flutter was diagnosed in 131,728 subjects (68,660 men and 63,068 women), and the incidence of a hospital diagnosis of atrial fibrillation or flutter more than doubled during the study period. The hazard ratios for mortality adjusted for 10-year age group, conditions of comorbidity and mortality trend in the Danish population in the last 5-year period compared to the first 5-year period were 0.80 (95% confidence interval 0.78-0.82) in men, and 0.82 (95% confidence interval 0.80-0.84) in women.

Conclusions: The incidence of a hospital diagnosis of atrial fibrillation or flutter more than doubled, and the 10-year age group- and comorbidity- and general population-adjusted mortality decreased, equally, from the first to the last 5-year period by 20% in men and 18% in women.