USPSTF reviews evidence, updates recommendations on abdominal aortic aneurysm screening

The U.S. Preventive Services Task Force recently reviewed published evidence and issued new, slightly revised draft recommendations on screening for abdominal aortic aneurysm (AAA).

The evidence review, published by Annals of Internal Medicine on Jan. 28, concluded that 1-time screening in men age 65 years or older was associated with decreased rate of AAA rupture and a 50% decrease in related mortality over 13 to 15 years, but not with a decline in all-cause mortality.

In the 4 randomized, controlled trials analyzed, AAA prevalence varied from 4.0% to 7.7% in men. Most (70% to 82%) screen-detected aneurysms were less than 4 cm to 4.5 cm. Aneurysms measuring 5.5 cm or greater were detected in only 0.4% to 0.6% of the screened groups.

Screening was associated with more overall and elective surgeries but fewer emergency operations and lower 30-day operative mortality rates at up to 10- to 15-year follow-up.

In the single trial that recruited women (9,342 women, 59% of participants), screening had no benefit on AAA-related or all-cause mortality rates. Prevalence in women was 6 times lower than in men (1.3% vs. 7.6%). Most (30 out of 40) of the aneurysms were 3 cm to 3.9 cm.

The recommendation for women was the only change that the USPSTF's new draft recommendation made to the Task Force's 2005 recommendations on screening for AAA. Instead of a D recommendation against screening for AAA in all women, the new recommendation concludes that there is insufficient evidence to assess the harms and benefits of screening in women ages 65 to 75 years who have ever smoked. There is still a D recommendation against screening any women who never smoked.

The Task Force continues to recommend 1-time screening in men ages 65 to 75 years who have ever smoked (B recommendation) and continues to recommend that clinicians selectively offer screening to men ages 65 to 75 years who have never smoked (C recommendation). In the latter group, patients and clinicians should consider the balance of benefits and harms on the basis of evidence relevant to the patient's medical history, family history, other risk factors, and personal values.

The Task Force's draft recommendation is online and open to public comment.

“Deaths due to AAA represented less than 3% of all deaths,” the review authors wrote. “We do not believe that the available data firmly support a reduction in all-cause mortality rates with AAA screening. It is important to note that although age is the strongest risk factor for AAA, competing causes of death and limited surgical candidacy due to comorbid conditions diminish the effectiveness of AAA screening.”