Preliminary ten year results from a randomised single centre mass screening trial for abdominal aortic aneurysm

At present, several regions and countries are considering screening for abdominal aortic aneurysm (AAA). However, The Chichester Aneurysms Screening Trial has reported poor long term benefit of screening for AAA. We therefore supplement previously published data with a preliminary analysis of the ten-year mortality from AAA, based upon population-based data until 2002 (7 years) and incomplete hospital-based information on deaths until 2005 (10 years).

In 1994 we started a randomised screening trial of 12,639 64-73 year-old males; 6,306 were controls, and 6,333 were invited to an abdominal ultrasound scan at their district hospital. Information on all deaths until 15.3.2005 was obtained from the Office of Civil Registration. Information on AAA related deaths was obtained from the national registry of Causes of Deaths from 1.4.1994 to 31.12.2001, and supplemented with AAA deaths known to the Danish National Patient Registry until 15.3.2005. Operations were obtained from the Danish National Vascular Registry from 1.4.1994 to 15.3.2005. Death certificates and medical records were reviewed by two independent assessors. The analyses were based on "intention to treat" from the date of randomisation.

The attendance rate was 76.6% and 191 (4.0%) had an AAA. The median observation time was 9.58 years. In the invited group 13 subjects were acutely operated on compared to 40 in the control group (Risk ratio: 0.32 (95% C.I. 0.17-0.60, P<0.001)), and 14 died due to AAA compared to 51 in the control group (Hazard ratio: 0.27 (95% C.I.: 0.15-0.49, P<0.001).

Over ten years, screening reduced mortality from AAA by 73%, and the frequency of emergency operations by 68%.