The influence of screening on the incidence of ruptured abdominal aortic aneurysms

Purpose: The purpose of this study was to estimate the influence of a scree ning program on the incidence and mortality of ruptured abdominal aortic an eurysms (RAAAs). Methods: The effects of screening on the incidence and death rate of RAAAs were investigated with a stepped wedge study design. RAAAs that occurred in the Huntingdon district were traced with an examination of all hospital re cords and community postmortem records. Results: During the 5-year period from 1991 to 1996, 78 RAAAs occurred in t he Huntingdon district: 62 in men and 16 in women. Eleven of the 62 men wit h RAAAs had been invited for screening. The incidence of RAAA in the invite d group was 3.7 per 10,000 person-years (py; 95% confidence interval [CI], 1.5 - 7.3). In the noninvited group, the incidence was 7.3 per 10,000 py (9 5% CI, 5.3. - 9.2), a rate ratio of 0.51 (95% CI, 0.26 - 0.97). The mortali ty of rAAAs in the invited,group was 3.0 per 10,000 py (95% CI, 1.4 - 5.4) as compared with 5.4 per 10,000 py in the noninvited group (95% CI, 3.9 - 7 .3), resulting in a rate ratio of 0.55 (95% CI, 0.26 - 1.15). Conclusion: Screening for asymptomatic AAAs can reduce the incidence rate o f RAAAs by 49% (95% CI, 3% - 74%).