A sustained mortality benefit from screening for abdominal aortic aneurysm

Abstract

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 infinity) per life-year gained based on all-cause death. (All values are reported in U.S. dollars [U.K. 1 pound sterling = 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.