Low prevalence of abdominal aortic aneurysm among 65-year-old Swedish men indicates a change in the epidemiology of the disease

Abstract

Background: Screening elderly men with ultrasound is an established method to reduce mortality from ruptured abdominal aortic aneurysm (AAA; Evidence Level 1a). Such programs are being implemented and generally consist of a single scan at 65 years of age. We report the results from screening 65-year-old men for AAA in middle Sweden.

Methods and results: All 65-year-old men (n=26,256), identified through the National Population Registry, were invited to an ultrasound examination. An AAA was defined as a maximum infrarenal aortic diameter of ≥30 mm. In total, 22 187 (85%) accepted, and 373 AAAs were detected (1.7%; 95% confidence interval, 1.5 to 1.9). With 127 previously known AAAs (repaired/under surveillance) included, the total prevalence of the disease in the population was 2.2% (95% confidence interval, 2.0 to 2.4). Self-reported smoking (odds ratio, 3.4; P<0.001), coronary artery disease (odds ratio, 2.0; P<0.001), and hypertension (odds ratio, 1.6; P=0.001) were independently associated with AAA in a multivariate logistic regression model. Thirteen percent of the entire population reported to be current smokers, one third of the frequency reported in the 1980s. The observed low prevalence of AAA was explained mainly by this change in smoking habits.

Conclusions: On the basis of the observed reduced exposure to risk factors, lower-than-expected prevalence of AAA among 65-year-old men, unchanged AAA repair rate, and significantly improved longevity of the elderly population, the current generally agreed-on AAA screening model can be questioned. Important issues to address are the threshold diameter for follow-up, the possible need for rescreening at a higher age, and selective screening among smokers.