Clinical risk indicators for formation of abdominal aortic aneurysms

Background. Evidence for ultrasound screening of abdominal aortic aneurysms (AAA) has been confirmed in several international studies. The efficiency could be increased by taking into account additional information about risk factors and secondary diagnoses to reduce the number of persons to be examined. Material and methods. Population-based studies from 2000 to 2014 concerning AAA screening were analyzed under the aspect of clinical risk factors. All randomized controlled studies (RCT) for AAA screening and health technology assessment (HTA) reports about clinical risk indicators were analyzed. The following variables were looked for: age, gender, smoking, family history, cardiovascular disease, peripheral arterial occlusive disease (PAOD), hypertension, obesity, chronic obstructive pulmonary disease (COPD), hypercholesterolemia and diabetes mellitus. In addition, a short survey of rarely studied clinical variables is given. Results. For the following risk factors a positive correlation for the development of AAA was found: body mass index (BMI), increasing age, male gender, nicotine history and a positive family history for AAA. Coronary artery disease (CAD), COPD and PAOD as comorbidities represent a significantly increased prevalence of AAA. Uncertain results and insufficient research results exist for obesity, hypercholesterolemia, COPD, physical activity and nutrition. The risk factors diabetes mellitus, non-white skin color as well as feminine sex were associated with a decreased probability of AAA. Discussion. Many of the known risk factors for atherosclerosis are also associated with an increased prevalence of AAA; however, this is not always true. For example, female sex, diabetes mellitus and certain increases in fat metabolism are associated with a decreased prevalence. For female sex a differentiated approach should be recommended as a more sophisticated analysis is able to identify sig-nificant risk factors that need to be taken into account because women have a significantly increased risk of rupture and form a large proportion of the cases of rupture. A sophisticated algorithm for the identification of individuals who would benefit from individualized indications for aortic screening could reduce the number needed to screen per identified aortic aneurysm. Conclusion. In consideration of evident clinical risk factors, further groups of patients could be defined which could - particularly benefit from AAA screening. Under this aspect, population-based prospective studies are necessary.