Prevalence of abdominal aortic aneurysms and iliac aneurysms in the UK population of 50,000 women

BACKGROUND AND AIMS: Screening men aged 65–80 years for abdominal aortic aneurysm (AAA) is considered economically viable when the prevalence of AAA is 1.0% or higher. Currently, women are not included in AAA screening programs because the prevalence of AAA is 1.0%. MATERIALS AND METHODS: Risk factors were collected from 50,000 females who attended for cardiovascular screening. Ultrasound was used to detect the presence of AAA or IIA, the severity of carotid atherosclerosis, and the measurement of ankle/brachial index (ABI). Electrocardiogram (ECG) was used to detect the presence of atrial fibrillation (AF). RESULTS: Aneurysms were detected in 116 women. Of these aneurysms, 34 (29%) were IIA and 82 were AAA. The presence of AAA or IA below the age of 66 years was rare (10 of 24,499). In the age group of 66–85, there were 102 (0.41%) in 27,170 women, of which 72 were AAA and 30 IIA. By including IIA in the screening protocol for AAA, it became easy to identify subgroups with an aneurysm prevalence >1%. Univariate analysis demonstrated that the presence of any one of the following risk factors, history of myocardial infarction or coronary artery disease, history of stroke/transient ischemic attack (TIA), pack-years ≥10, AF, ABI 1.0% (range 1.18–2.06). In a multivariable linear logistic regression, age ≥76, hypertension, pack-years, family history of AAA, and history of stroke/TIA were independent predictors for the presence of AAA or IIA. This model had an area under the receiver operator characteristic curve (AUC) of 0.725 (95% confidence interval [CI] 0.673–0.777) and could identify 2947 women who had 41 AAA or IIA present (prevalence 1.39%). By adding ABI and AF, which require a clinical examination and ECG, the receiver operator characteristic (ROC), AUC increased to 0.745 (95% CI 0.693–0.797). This model could identify 3693 women who had 51 AAA or IIA present (prevalence 1.40%). The presence of ≥50% diameter internal carotid stenosis found in 498 women was associated with a prevalence of AAA or IIA of 3.61%, and when added to the model the ROC AUC increased to 0.775 (95% CI 0.724–0.826). This model could identify 3701 women who had 58 AAA or IIA present (prevalence 1.6%). CONCLUSION: The findings of this study have important implications for developing a screening selection plan for women over 65. By including IIA in the screening protocol for AAA, it became easy to identify subgroups with an aneurysm prevalence >1%. The presence of any one or more of the risk factors listed above can be used to develop targeted screening because of increased risk (>1%). However, whether such screening will be associated with benefits can only be determined by randomized controlled trials and cost-benefit studies