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Is Screening for Abdominal Aortic Aneurysms Worthwhile?

Screening in these men saved lives over a 4-year period, and the screening program was relatively cost-effective.

Ultrasound can detect abdominal aortic aneurysms (AAAs) before they are likely to rupture. However, it is unclear whether the overall benefits of screening for AAAs outweigh the potential harms. In this randomized study, British researchers evaluated ultrasound screening in 67,800 men (age range, 65 to 74) who were identified from family-doctor lists: The men were offered abdominal ultrasound scans or were not offered scans. Intervention subjects with AAAs of at least 3-cm diameter on ultrasound underwent periodic repeat scanning during follow-up. Surgery was offered when aneurysms reached 5.5 cm in diameter or expanded at a rate of 1 cm per year, or if patients developed symptoms.

Of the 33,839 men who were offered screening, 27,147 underwent initial scans: 1,333 aneurysms were detected (4.9% of scanned men). During an average follow-up of 4 years, 65 AAA-related deaths occurred in the intervention group, and 113 occurred in the control group -- a significant difference. Most of this difference was attributable to deaths from ruptured AAAs among controls. Elective operations, which were carried out in 322 intervention subjects and 92 controls, were associated with a 30-day mortality rate of 6%. In contrast, emergency operations, which were performed in 27 intervention subjects and 54 controls, were associated with a 30-day mortality rate of 37%. All-cause mortality did not differ significantly between groups.

The researchers also performed a cost-effectiveness analysis using data from this trial. The total additional cost in the intervention group was GB£2.2 million (US$3.5 million), with screening costing a mean of GB£23.23 (US$37.14) per person. The cost per year of life gained at 4 years was estimated at GB£28,400 (US$45,400). The researchers determined that the cost-effectiveness of screening would improve with the passage of time, resulting in an estimated GB£8,000 (US$12,800) per life-year gained at 10 years.

Comment: These results suggest that AAA screening in men would save some lives over several years, and that the cost-effectiveness of a screening program would compare favorably with that of other commonly accepted medical interventions. However, there are many unanswered questions, from both medical and economic perspectives, about how screening would play out on a nationwide scale. At the time of publication, the full text of the second original article was available at http://bmj.com/cgi/content/full/325/7373/1135 free of charge.

— Sir Brian Jarman, PhD, FRCP, FRCGP, FFPHM, FmedSci; Keith I. Marton, MD; and Allan S. Brett, MD

Published in Journal Watch General Medicine January 3, 2003

Citation(s):

Ashton HA et al. for the Multicentre Aneurysm Screening Study Group. The Multicentre Aneurysm Screening Study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: A randomised controlled trial. Lancet 2002 Nov 16; 360:1531-9.

• Medline abstract (Free)

Multicentre Aneurysm Screening Study Group. Multicentre aneurysm screening study (MASS): Cost effectiveness analysis of screening for abdominal aortic aneurysms based on four year results from randomised controlled trial. BMJ 2002 Nov 16; 325:1135-8.

• Original article (Subscription may be required)
• Medline abstract (Free)