Risk factors for asymptomatic abdominal aortic aneurysm: systematic review and meta-analysis of population-based screening studies

BACKGROUND: The incidence of and mortality from ruptured abdominal aortic aneurysm (AAA) is increasing. There is uncertainty regarding the indicators which could be used to identify groups at high risk. This issue has been addressed in a systematic review of population-based screening studies. METHODS: MEDLINE and EMBASE were searched, reference lists scanned and manual searches made of eight journals. The search was restricted to four languages (English, German, French and Italian). Population-based studies investigating risk factors associated with screening-detected AAA were included. The following risk factors were considered: sex, smoking, hypertension, diabetes, a history myocardial infarction, and peripheral vascular disease. RESULTS: Fourteen cross-sectional studies met our inclusion criteria. Most studies screened people aged 60 years or older. The prevalence of AAA ranged from 4.1% to 14.2% in men and from 0.35% to 6.2% in women. Male sex showed a strong association with AAA (OR 5.69), whereas smoking (OR 2.41), a history of myocardial infarction (OR 2.28) or peripheral vascular disease (OR 2.50) showed moderate associations. Hypertension was only weakly associated with AAA (OR 1.33) and no association was evident with diabetes (OR 1.02). CONCLUSIONS: The efficacy of screening men aged 60 years or older and women of the same age who smoke or have a history of peripheral or coronary artery disease should be evaluated in randomized controlled trials.