Long term outcomes in men screened for abdominal aortic aneurysm: prospective cohort study.

Objective: To determine whether there is a relation between aortic diameter and morbidity and mortality in men screened for abdominal aortic aneurysm.

Design: Prospective cohort study.

Setting: Highland and Western Isles (a large, sparsely populated area of Scotland).

Participants: 8146 men aged 65-74.

Main Outcome Measures: Morbidity and mortality in relation to presence of abdominal aortic aneurysm and three categories of aortic diameter (≤ 24 mm, 25-29 mm, and ≥ 30 mm).

Results: When screened, 414 men (5.1%) had an aneurysm (diameter ≥ 30 mm), 669 (8.2%) an aortic diameter of 25-29 mm, and 7063 (86.7%) an aortic diameter of ≤ 24 mm. The cohort was followed up for a median of 7.4 (interquartile range 6.9-8.2) years. Mortality was significantly associated with aortic diameter: 512 (7.2%) men in the ≤ 24 mm group died compared with 69 (10.3%) in the 25-29 mm group and 73 (17.6%) in the ≥ 30 mm group. The mortality risk in men with an aneurysm or with an aorta measuring 25-29 mm was significantly higher than in men with an aorta of ≤ 24 mm. The increased mortality risk in the 25-29 mm group was reduced when taking confounders such as smoking and known heart disease into account. After adjustment, compared with men with an aortic diameter of ≤ 24 mm, the risk of hospital admission for cardiovascular disease and chronic obstructive pulmonary disease was significantly higher in men with aneurysm and those with aortas measuring 25-29 mm. Men with an aneurysm also had an increased risk of hospital admission for cerebrovascular disease, atherosclerosis, peripheral arterial disease, and respiratory disease. In men with aortas measuring 25-29 mm, the risk of hospital admission with abdominal aortic aneurysm was significantly higher than in men with an aorta of ≤ 24 mm (adjusted hazard ratio 6.7, 99% confidence interval 3.4 to 13.2) and this increased risk became apparent two years after screening.

Conclusions: Men with abdominal aortic aneurysm and those with aortic diameters measuring 25-29 mm have an increased risk of mortality and subsequent hospital admissions compared with men with an aorta diameter of ≤ 24 mm. Consideration should be given to control of risk factors and to rescreening men with aortas measuring 25-29 mm at index scanning.