Screening men for abdominal aortic aneurysm: 10 year mortality and cost effectiveness results from the randomised Multicentre Aneurysm Screening Study

Abstract

Objectives: To assess whether the mortality benefit from screening men aged 65-74 for abdominal aortic aneurysm decreases over time, and to estimate the long term cost effectiveness of screening.

Design: Randomised trial with 10 years of follow-up.

Setting: Four centres in the UK. Screening and surveillance was delivered mainly in primary care settings, with follow-up and surgery offered in hospitals.

Participants: Population based sample of 67 770 men aged 65-74.

Interventions: Participants were individually allocated to invitation to ultrasound screening (invited group) or to a control group not offered screening. Patients with an abdominal aortic aneurysm detected at screening underwent surveillance and were offered surgery if they met predefined criteria.

Main outcome measures: Mortality and costs related to abdominal aortic aneurysm, and cost per life year gained.

Results: Over 10 years 155 deaths related to abdominal aortic aneurysm (absolute risk 0.46%) occurred in the invited group and 296 (0.87%) in the control group (relative risk reduction 48%, 95% confidence interval 37% to 57%). The degree of benefit seen in earlier years of follow-up was maintained in later years. Based on the 10 year trial data, the incremental cost per man invited to screening was pound100 (95% confidence interval pound82 to pound118), leading to an incremental cost effectiveness ratio of pound7600 ( pound5100 to pound13,000) per life year gained. However, the incidence of ruptured abdominal aortic aneurysms in those originally screened as normal increased noticeably after eight years.

Conclusions: The mortality benefit of screening men aged 65-74 for abdominal aortic aneurysm is maintained up to 10 years and cost effectiveness becomes more favourable over time. To maximise the benefit from a screening programme, emphasis should be placed on achieving a high initial rate of attendance and good adherence to clinical follow-up, preventing delays in undertaking surgery, and maintaining a low operative mortality after elective surgery. On the basis of current evidence, rescreening of those originally screened as normal is not justified. Trial registration Current Controlled Trials ISRCTN37381646.

Fig 1 Cumulative deaths related to abdominal aortic aneurysm, by time since randomisation

Fig 2 Rate of ruptured abdominal aortic aneurysms (number of ruptures in brackets) in men originally screened as normal, by time since randomisation. Three more ruptures were recorded in the limited follow-up after 10 years