A sustained mortality benefit from screening for abdominal aortic aneurysm

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% Cl, 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 (Cl, 0.25 to 1.02 ruptures) per 10 000 person-years. In terms of all-cause mortality, the observed hazard ratio was 0.96 (Cl, 0.93 to 1.00). At the 7-year follow-up, cost-effectiveness was estimated at $19 500 (Cl, $12 400 to $39 800) per life-year gained based on AAA-related mortality and $7600 (Cl, $3300 to infinity) per life-year gained based on all-cause death. (All values are reported in U.S. dollars [U.K. 1 pound = 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.