About 4% of men and 1% of women over the age of 65 have an abdominal aortic aneurysm (AAA). When this aneurysm ruptures the mortality rate is about 80%. Thus it is not surprising that screening for this condition in patients (mostly men) with abdominal ultrasound has become prevalent over the last decade or so. As is typical of my profession, were just now getting around to assessing how effective this screening is. An Australian study just published in the JAMA shows no beneficial effect from indiscriminate screening of 65+ year old men.
This raises the question of whether targeted screening might be useful. Smoking and hypertension are big risk factors for vascular disease including AAA. So would there be benefit to limiting screening to this subset of individuals? We need more data to answer this question, but my guess is that there would not be much benefit from this narrowed screening. My reason is that smokers and patients with hypertension are at such high risk for so many other forms of vascular disease that focusing on just one would be lost in the morass of other smoking and hypertension related disease; but that’s just an educated surmise. The abstract of this study is below.
Long-term Outcomes of the Western Australian Trial of Screening for Abdominal Aortic Aneurysms
Secondary Analysis of a Randomized Clinical Trial
Kieran A. McCaul, PhD1; Michael Lawrence-Brown, MD2; James A. Dickinson, MB, PhD3,4; et al Paul E. Norman, MB, DS
Question Does screening older men for abdominal aortic aneurysms (AAAs) reduce mortality from AAAs in the long term?
Findings: In this randomized clinical trial of 38 480 men (aged 64-83 years) in Western Australia, use of administrative databases, such as the electoral roll, to identify and invite the men for AAA screening increased the detection rate and number of elective operations in the screened group, but mortality was not significantly reduced. It is unlikely that a national AAA screening program will be effective in an Australian health care setting.
Abstract
Mortality from ruptured abdominal aortic aneurysms (AAAs) remains high. The benefit of screening older men for AAAs needs to be assessed in a range of health care settings.
Objective: To assess the influence of screening for AAAs in men aged 64 to 83 years on mortality from AAAs.
Design, Setting, and Participants: This randomized clinical trial performed from April 1, 1996, through March 31, 1999, with a mean of 12.8 years of follow-up (range, 11.6-14.2 years) included a population-based sample from a single metropolitan region in Western Australia identified via the electoral roll. Data analysis was performed from June 1, 2015, to June 1, 2016.
Interventions: Randomization to an invitation to undergo ultrasonography of the abdominal aorta or a control group without invitation.
Results: A total of 49 801 men aged 64 to 83 years were identified for the study. Men living too far from screening centers (n = 8671) or who died before invitation (n = 2650) were excluded, resulting in 19 249 men in the invited group and 19 231 controls (mean [SD] age, 72.5 [4.6] years; 95% white). Of 19 249 men invited for screening, 12 203 (63.4%) attended. There were more elective operations (536 vs 414, P < .001) and fewer ruptured AAAs (72 vs 99, P = .04) in the invited group compared with the control group. Overall, there were 90 deaths from AAAs in the invited group (mortality rate, 47.86 per 100 000 person-years; 95% CI, 38.93-58.84) and 98 in the control group (52.53 per 100 000 person-years; 95% CI, 43.09-64.03) for a rate ratio of 0.91 (95% CI, 0.68-1.21). For men aged 65 to 74 years, the AAA mortality rate in the invited group was 34.52 per 100 000 person-years (95% CI, 26.02-45.81) compared with 37.67 per 100 000 person-years (95% CI, 28.71-49.44) in the control group for a rate ratio of 0.92 (95% CI, 0.62-1.36). The number needed to invite for screening to prevent 1 death from an AAA in 5 years was 4784 for men aged 64 to 83 years and 3290 for men aged 65 to 74 years. There were no meaningful differences in all-cause, cardiovascular, and other mortality risks.
Conclusions and Relevance: Use of the electoral roll to identify and invite men aged 64 to 83 years for screening for AAAs had no significant effect on the overall mortality from AAAs.
