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.