Increasing incidence of ruptured abdominal aortic aneurysm: A population-based study

Objective: The aim of the present population-based study was to assess the trends of age- and gender-specific incidence of ruptured abdominal aortic aneurysm (rAAA). Methods. Patients with rAAA from the city of Malmo, Sweden, were studied between 2000 and 2004. An analysis of trends of incidence and mortality of rAAA in Malmo was possible because of a previous population-based study on patients with rAAA between 1971 and 1986 (autopsy rate 85% compared with 25% for the time period 2000 to 2004). The in-hospital registry of Malmo University Hospital and the databases at the Department of Pathology, Malmo, and the Institution of Forensic Medicine, Lund, identified patients with rAAA, and the in-hospital registry identified all elective repairs for AAA. Results. Compared with the time period 1971 to 1986, the overall incidence of rAAA significantly increased from 5.6 (95 % confidence interval [CI], 4.9 to 6.3) to 10.6 (95% CI, 8.9 to 12.4) per 100,000 person-years (standardized mortality ratio, 1.6; 95% CI, 1.0 to 2.1). In men aged 60 to 69 and 70 to 79 years, the incidence increased significantly from 16 (95% CI, 11 to 21) and 56 (95% Cl, 43 to 69) to 46 (95% Cl, 28 to 63) and 117 (95% CI, 84 to 149) per 100,000 person-years, respectively, whereas no increase in the age-specific incidence in women could be demonstrated. The overall incidence of elective repair of AAA increased significantly from 3.4 (95% CI, 2.8 to 4.0) to 7.0 (95% CI, 5.6 to 8.4) per 100,000 person-years and increased most significantly from 12 (95% CI, 3.4 to 32) to 68 (95% CI, 34 to 102) per 100,000 person-years in men aged 80 to 89 years and from 5.1 (95% CI, 2.4 to 9.3) to 28 (95% CI, 15 to 41) per 100,000 person-years in women aged 70 to 79 years. The elective-acute repair ratio in women increased from 2.4 to 5.6 and decreased in men from 2.1 to 1.0. Conclusions: Between 1971 to 1986 and 2000 to 2004, the incidence of rAAA increased significantly, despite a 100% increase in elective repairs and notwithstanding a potential for bias towards underestimation due to lower autopsy rates in recent years. The reason behind this increase is unclear, and further studies are needed to identify risk groups for direction of effective prevention and screening.