1. Based on a systematic review, the U.S. Preventive Services Task Force (USPSTF) has released a statement recommending one-time ultrasonography screening for asymptomatic abdominal aortic aneurysms (AAAs) in men 65-75 years old who have a history of smoking (B recommendation).
Evidence Rating Level: 1 (Excellent)
Study Rundown: There is particular interest in the benefits of screening for abdominal aortic aneurysms (AAA). AAAs are associated with high mortality after rupture, but unfortunately usually remain asymptomatic and undetected until this point. Based on a recent commissioned systematic review, the USPSTF has released a recommendation statement pertaining to ultrasonography AAA screening. Primarily, the statement recommends that clinicians offer one-time screening to male patients aged 65-75 years old who have a history of past or present smoking (B recommendation). This statement was based on four large randomized control trials (RCTs) in men, of which the two of the highest-quality trials of showed a relative reduction in AAA-specific mortality of 42-66% associated with one-time AAA screening. AAAs are most prevalent in men who have ever smoked (6-7%), and thus, the highest absolute benefit can be achieved in this particular patient population.
Although screening in men overall reduces poor outcomes associated with AAA, given the lower prevalence of AAAs in in men who have never smoked, the net benefit of screening in this group is small. The statement also recommended against ultrasound screening for AAA in women who have never smoked (D recommendation), but identified that that there is insufficient evidence to assess screening in woman who have a history of smoking (I statement).
In-Depth [systematic review]: This recommendation statement applies to asymptomatic patients greater than 50 years old. The systematic review identified four large RCTs in men, which showed that one-time screening was associated with a 42-66% relative reduction in AAA-specific mortality. Only one RCT identified included woman, which showed no difference in AAA related outcomes among women. Given the relatively low prevalence in women who have smoked (0.8-2%), the USPSTF concluded that there was inadequate evidence to determine the benefits and harms of screening in women who have smoked aged 65 to 75 years old. However, in women who have never smoked, the prevalence of AAA is very low (0.3%) and therefore, the USPSTF have recommended against screening among this population. The recommendation statement also reviewed the harms of detection and early treatment. In the reviewed trials, the screened groups were more likely to undergo AAA surgery (mostly elective). However, the mortality risk of elective is less than that associated with acute AAA rupture.
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