A Sustained Mortality Benefit from Screening for Abdominal Aortic Aneurysm

15 May 2007 | Volume 146 Issue 10 | Pages 699-706

Background: Longer-term mortality benefit and cost-effectiveness for abdominal aortic aneurysm (AAA) screening are uncertain.

Objective: To estimate the benefits, in terms of AAA-related and all-cause mortality, and cost-effectiveness of ultrasonography screening for AAA in a group that was invited to screening compared with a group that was not invited at a mean 7-year follow-up.

Design: Randomized trial.

Setting: 4 centers in the United Kingdom.

Patients: Population-based sample of 67 770 men age 65 to 74 years.

Intervention: Patients with an AAA detected at screening had surveillance and were offered surgery after predefined criteria were met.

Measurements: Mortality data were obtained after flagging on the national database. Unit costs obtained from large samples were applied to individual event data for the cost analysis.

Results: The hazard ratio was 0.53 (95% CI, 0.42 to 0.68) for AAA-related mortality in the group invited for screening. The rupture rate in men with normal results on initial ultrasonography has remained low: 0.54 rupture (CI, 0.25 to 1.02 ruptures) per 10 000 person-years. In terms of all-cause mortality, the observed hazard ratio was 0.96 (CI, 0.93 to 1.00). At the 7-year follow-up, cost-effectiveness was estimated at $19 500 (CI, $12 400 to $39 800) per life-year gained based on AAA-related mortality and $7600 (CI, $3300 to ) per life-year gained based on all-cause death. (All values are reported in U.S. dollars [U.K. £1 = U.S. $1.58]).

Limitation: Inclusion of deaths from aortic aneurysm at an unspecified site, which may include some thoracic aortic aneurysms, may have underestimated the treatment effect.

Conclusions: These results from a large, pragmatic randomized trial show that the early mortality benefit of screening ultrasonography for AAA is maintained in the longer term and that the cost-effectiveness of screening improves over time.

International Standard Randomized Controlled Trial registration number: ISRCTN37381646.

Editors' Notes Context Is it cost-effective to screen older adults for abdominal aortic aneurysm (AAA)? Contribution This 7-year follow-up report of a large randomized trial in the United Kingdom found that men age 65 to 74 years who were invited to have ultrasonography and surveillance for AAA had lower mortality rates than did those who were not invited (hazard ratio, 0.53 [CI, 0.42 to 0.68]). Cost-effectiveness for AAA-related deaths, based on costs applied to the events experienced by the men, was estimated at $19 500 (CI, $12 400 to $39 800) per life-year gained. Cautions Only men were studied. Actual costs of screening and surveillance may vary substantially in different settings. —The Editors

 

Author and Article Information

From the Institute of Public Health, Cambridge, United Kingdom, and St. Richard's Hospital, Chichester, United Kingdom.

Acknowledgment: The authors thank Professor Martin Buxton for comments on a previous version of this paper.

Grant Support: By the U.K. Medical Research Council. Ms. Kim receives a Raymond and Beverly Sackler Studentship Award.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Lois G. Kim, MSc, MRC Biostatistics Unit, Institute of Public Health, Robinson Way, Cambridge CB2 2SR, United Kingdom; e-mail, lois.kim{at}mrc-bsu.cam.ac.uk.

Current Author Addresses: Ms. Kim and Dr. Thompson: MRC Biostatistics Unit, Institute of Public Health, Robinson Way, Cambridge CB2 2SR, United Kingdom.

Mr. Scott and Ms. Ashton: Scott Research Unit, Chichester Medical Education Centre, St. Richard's Hospital, Spitalfield Lane, Chichester PO19 6SE, United Kingdom.

Author Contributions: Conception and design: R.A.P. Scott, H.A. Ashton.

Analysis and interpretation of the data: L.G. Kim, R.A.P. Scott, H.A. Ashton, S.G. Thompson.

Drafting of the article: L.G. Kim, R.A.P. Scott, H.A. Ashton.

Critical revision of the article for important intellectual content: L.G. Kim, R.A.P. Scott, S.G. Thompson.

Final approval of the article: L.G. Kim, R.A.P. Scott, H.A. Ashton, S.G. Thompson.

Statistical expertise: L.G. Kim, S.G. Thompson.

Obtaining of funding: R.A.P. Scott, S.G. Thompson.

Administrative, technical, or logistic support: R.A.P. Scott, H.A. Ashton.

Collection and assembly of data: R.A.P. Scott, H.A. Ashton.

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