Fifteen-year follow-up of a randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms

Background: Long-term benefits of screening for abdominal aortic aneurysm (AAA) are uncertain. These are the final results of a randomized controlled screening trial for AAA in men, updating those reported previously. Benefit and compliance over a median 15-year interval were examined. Methods: One group of men were invited for ultrasonographic AAA screening, and another group, who received standard care, acted as controls. A total of 6040 men aged 65-80 years were randomized to one of the two groups. Outcome was monitored in terms of AAA-related events (surgery or death). Results: In the group invited for screening, AAA-related mortality was reduced by 11 per cent (from 1.8 to 1.6 per cent, hazard ratio 0.89) over the follow-up interval. Screening detected an AAA in 170 patients; 17 of these died from an AAA-related cause, seven of which might have been preventable. The incidence of AAA rupture after an initially normal scan increased after 10 years of follow-up, but was still low overall (0.56 per 1000 person-years). Conclusion: Screening with a single ultrasonography scan still conferred a benefit at 15 years, although the results were not significant for this population size. Fewer than half of the AAA-related deaths in those screened positive could be prevented. Registration number: ISRCTN 00079388 (http://www.controlledtrials.com).