OBJECTIVE(S): Current screening criteria for Abdominal Aortic Aneurysm (AAA) are designed to identify >3cm aneurysms in ever smoking 65-75yo males. However, more than 50% of ruptures occur in individuals not within this patient cohort and only a subset of AAAs detected are large enough to warrant surgery. In this analysis, we evaluated over 3 million screened individuals and developed a scoring tool that allows identification of ≥5cm AAAs in the entire population at risk.
METHODS: From 2003-2008, demographics and risk factors were collected from 3.1 million patients undergoing ultrasound screening for AAA by Life Line Screening. Using multivariable logistic regression analysis, we identified risk factors and developed a scoring system to predict the presence of (≥5cm) AAAs .
RESULTS:Smoking had a profound influence on the risk of AAA, which increased with cigarettes smoked and years of smoking and decreased following smoking cessation. Novel findings included a protective effect of exercise, healthy diet, normal weight and black/Hispanic ethnicity. Using these and other factors, a simple scoring system was created with good predictive accuracy (c-statistic=0.76). Using this scoring system we estimated the presence of 130,000 [95%CI:110,000-150,000] ≥5cm aneurysms in the US population (prevalence: 0.16%). Demonstrating the inadequacy of the current screening recommendations, half of AAAs were among females, non-smokers and individuals younger than 65.
CONCLUSIONS: Based upon the largest cohort of patients ever screened for AAA, we have developed a novel easily implemented screening strategy that, when compared to current guidelines, identifies large AAAs in a broad population of individuals at risk.