The USPSTF released its recommendations on screening for AAA on 1 February 2005. The USPSTF recommends 1-time screening for men 65 to 75 years of age who have ever smoked. The recommendation is based on the high prevalence of AAA in this population, their high risk for AAA rupture, and the good-quality evidence from large population-based screening trials showing that screening leads to decreased AAA-specific mortality in men. The USPSTF makes no recommendation for or against screening men 65 to 75 years of age who have never smoked because the balance of harms and benefits is too close to call. Prevalence of AAA is lower in men who have never smoked than in those who have ever smoked and, therefore, the potential for benefit in this population is lower when balanced against important harms. Finally, the USPSTF recommends against routine primary care screening for women on the basis of 3 important pieces of evidence: 1) The prevalence of AAA in women is low compared with its prevalence in men (1.3% vs. 7.6%); 2) the peak prevalence of AAA in women is 10 years later than it is for men and AAAs in women therefore occur at ages when there are important competing causes of mortality; and 3) the available trial evidence shows no benefit from screening and repairing AAAs in women (1, 2).

Contrary to Dr. Cronenwett's assertion, the USPSTF did not base its concerns about AAA screening on psychological harms or the harms of unnecessary surgeries. The USPSTF considered both the benefits and harms of screening and early intervention associated with AAA screening. The USPSTF carefully assessed the evidence of harms and concluded that the harms of surgery for AAAs greater than 5.5 cm are important ones: 4% to 6% in-hospital mortality rates and 32.4% major complication rates (2). Higher rates of complications are anticipated in older women, that is, at the ages when women develop AAAs. Therefore, it is likely that the net benefit of screening these women for AAA is, at best, zero. It is for these reasons that the USPSTF recommends against screening women for AAA. According to USPSTF methodology (3), the demonstration of no net benefit is sufficient for the USPSTF to recommend against providing a preventive service; no evidence of net harms is needed.

Dr. Cronenwett points out that AAA prevalence in female smokers is about the same as it is in male nonsmokers. He disagrees with the USPSTF for making no recommendation for or against screening men who have never smoked for AAA and for recommending against screening women. The combination of low prevalence, late age of onset, and the negative results from the available screening trial in women explains the reasons for not screening women for AAA (1, 2). The Task Force recognizes, however, that individualization of care is still required. For example, a clinician may choose to discuss screening in the unusual circumstance in which a healthy female smoker in her early 70s has a first-degree family history of AAA that required surgery.

The USPSTF found poor-quality evidence that family history is associated with an increased risk for AAA. Studies by Larcos and Webster and colleagues (4, 5), which involved ultrasonographic examination of relatives of patients with AAA, found the prevalence of AAA to be much lower—0% and 4%, respectively—than that reported by Frydman and associates (6). Small sample sizes in all studies of relatives of patients with AAA translated into large confidence intervals.

In conclusion, the USPSTF used the best available evidence on the risk factors for AAA and the benefits and harms of screening and treatment to recommend in favor of screening men 65 to 75 years of age who have ever smoked. In such cases, there is evidence that AAA screening can save lives.