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Evidence summaries

Screening for Abdominal Aortic Aneurysm

One-time ultrasound screening for abdominal aortic aneurysm (AAA) in men aged> 65 years appears to be effective in reducing AAA related mortality and might possibly reduce all cause mortality. Level of evidence: "B"

The quality of evidence is downgraded by study limitations (unclear allocation concealment and blinding).

Summary

A Cochrane review [Abstract] 1 included 4 studies with a total of 137 233 male and female subjects (only one study included women, n=9 342). Results for men and women were analysed separately. Three to five years after screening there was no significant difference in all-cause mortality between screened and unscreened groups for men or women (for men OR 0.95, 95% CI 0.85 to 1.07; for women OR 1.06, 95% CI 0.93 to 1.21). There was a significant decrease in mortality from AAA in men (OR 0.60, 95% CI 0.47 to 0.78), but not for women (OR 1.99, 95% CI 0.36 to 10.88). In this analysis mortality includes death from rupture and from emergency or elective surgery for aneurysm repair. There was also a decreased incidence of ruptured aneurysm in men (OR 0.45, 95% CI 0.21 to 0.99) but not in women (OR 1.49, 95% CI 0.25 to 8.94). There was a significant increase in surgery for AAA in men (OR 2.03, 95% CI 1.59 to 2.59). This was not reported in women. There were no data on life expectancy, complications of surgery or subjective quality of life. The MASS study has published a cost effectiveness analysis of the benefits of AAA screening. The study identified 47 fewer deaths over 4 years due to AAA, at an additional cost of £2.2 million. This equated to £28,400 per life year gained, and approximately £36,000 per QALY (Quality Adjusted Life Year). After 10 years this is estimated to fall to about £8,000 per life year gained. The Viborg trial identified outline hospital costs with an estimate of costs outside hospital. They derived a figure of DKK 7540 per life year saved (£1 = 12 DKK).

A systematic review 2 included 4 randomized studies with a total of 125 576 men aged > 65 years comparing 1-time ultrasound screening vs. no screening. Screening was associated with reduced short-term (3-5 years) AAA mortality (RR 0.57, 95% CI 0.44 to 0.72; number needed to screen [NNS] 796), long-term (13-15 years) AAA mortality (RR 0.66, 95% CI 0.47 to 0.93, statistical heterogeneity I2 =80%; NNS 311), and reduced AAA rupture rate in short (RR 0.52, 95% CI, 0.35 to 0.79, statistical heterogeneity I2 =58%; NNS 606) and long-term follow-up (RR 0.65, 95% CI 0.51 to 0.82, statistical heterogeneity I2 =56%; NNS 264). The effect on all-cause mortality was nonsignificant for short-term follow-up (RR 0.94, 95% CI 0.88 to 1.02, statistical heterogeneity I2 =81%) and marginally significant for long-term follow-up (RR 0.99, 95% CI 0.98 to 1.00). One-time AAA screening was associated with an increase in the number of elective AAA-related procedures.

A systematic review 3 including the same 4 studies as the Cochrane review was abstracted in DARE. Conclusions were similar. The review also evaluated repeated screening following negative results on ultrasonography. Overall, a single negative ultrasonography screen at age 65 years appeared to virtually exclude any future risk of AAA rupture or death.

The following decision support rules contain links to this evidence summary:

    References

    • Cosford PA, Leng GC. Screening for abdominal aortic aneurysm. Cochrane Database Syst Rev 2007 Apr 18;(2):CD002945. [PubMed]
    • Ali MU, Fitzpatrick-Lewis D, Kenny M et al. A systematic review of short-term vs long-term effectiveness of one-time abdominal aortic aneurysm screening in men with ultrasound. J Vasc Surg 2018;68(2):612-623. [PubMed]
    • Fleming C, Whitlock EP, Beil TL, Lederle FA. Screening for abdominal aortic aneurysm: a best-evidence systematic review for the U.S. Preventive Services Task Force. Ann Intern Med 2005 Feb 1;142(3):203-11. [PubMed][DARE]

Primary/Secondary Keywords