Medicare Coverage Has Done Little to Improve AAA Screening in At-Risk Patients

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Since the beginning of 2007, patients with specific risk factors enrolling in Medicare have been eligible for abdominal aortic aneurysm (AAA) screening under the SAAAVE Act. But a new study published online September 17, 2012, ahead of print in the Archives of Internal Medicine, suggests the Act has led only to a “modest” rise in screening without any significant effect on AAA repair or rupture, or on all-cause mortality risk.

SAAAVE (Screening Abdominal Aortic Aneurysms Very Efficiently) covers a 1-time ultrasound to screen for AAA in men aged 65 years who have smoked at least 100 cigarettes and in women who have family history of the disease. To qualify for coverage, the screening and the Welcome to Medicare physical examination must both occur within the first year of enrollment.

To gauge the Act’s impact, Jacqueline Baras Shreibati, MD, of the Stanford University School of Medicine (Stanford, CA), and colleagues looked at a random sample that comprised 20% of the 3.5 million male fee-for-service Medicare beneficiaries from 2004 to 2008. Researchers compared the 65-year-old male target population with control groups of 70-year-old and 76-year-old male beneficiaries as well as with 65-year-old female beneficiaries.

Small Changes Seen

A total of 185,098 men aged 65 years enrolled in the program in 2004 and 2005, before implementation of SAAAVE, and 189,212 men joined in 2007 and 2008.

Fewer than 3% of abdominal ultrasound claims after 2007 were specifically coded for SAAAVE. However, there was a greater increase in abdominal ultrasounds performed among SAAAVE-eligible 65-year-old men from 2004 to 2008 than among any of the control groups (P < 0.001 for all comparisons; table 1).

Table 1. Rates of Abdominal Ultrasound Use

Despite the added risk of AAA imparted by smoking, states with higher smoking prevalence did not see greater uptake of screening.

Multivariate adjustment showed a slight increase in the use of abdominal ultrasound—whether coded for SAAAVE or not—among eligible 65-year-old men compared with 70-year-old men, but there were no signs that the shift led to any change in clinical outcome (table 2). Similar patterns were seen when comparing SAAAVE-eligible beneficiaries with the other 2 control groups.

Table 2. Effect of the SAAAVE Act in 65- vs. 70-Year-Old Men

During the study period, only 17 of the 65-year-old men (< 0.01%) were hospitalized for AAA rupture and 238 underwent elective AAA repair (0.06%). Approximately 40% of such repairs were endovascular in 2004, though the proportion rose to over 60% in 2008. The all-cause death rate in 65-year-old men was 1.3% from 2004 to 2008.

Myriad Obstacles to More Screening

“Although the SAAAVE Act appears to have increased the rate of abdominal ultrasonography use among 65-year-old men joining Medicare, its overall impact was modest,” Dr. Shreibati and colleagues conclude.

One reason for the small effect, they explain, is that abdominal ultrasound not reimbursed under the program simultaneously increased. The Act may have encouraged physicians to screen for AAA even among patients who were not eligible for reimbursement (such as nonsmokers). Moreover, because criteria for SAAAVE reimbursement are complex, physicians may have chosen different codes thought more likely to result in payment.

“The reasons for the low rates of AAA screening are uncertain,” but the expense of ultrasound is only 1 barrier, the investigators emphasize. “Other barriers to screening include system factors, such as lack of physician reminders, limited access, and low patient awareness of disease risk. Direct invitation of beneficiaries for AAA screening may increase participation rates.”

In short, the findings suggest “that simply providing coverage for a screening test may not be sufficient to lead to widespread adoption,” they comment.

AAA as a Moving Target

But in an editorial accompanying the paper, Russell Harris, MD, MPH, Stacey Sheridan, MD, MPH, and Linda Kinsinger, MD, MPH, all of the University of North Carolina, Chapel Hill (Chapel Hill, NC), assert that increased AAA screening is a questionable goal.

“Many will see the findings of [Shreibati et al] as yet another example of unjustifiably slow diffusion of effective medical care into actual clinical practice. We suggest a different interpretation,” they write. “Sometimes rapid diffusion is not desirable. Sometimes it takes time to fully understand the effects of a new screening policy within the context in which it is introduced.”

Much has changed since the US Preventive Services Task Force recommended screening for AAA in 2005, Dr. Harris and colleagues note. Evidence suggests that AAA incidence is decreasing as smoking and MI rates drop. “Thus, the potential benefit from AAA screening is decreasing,” they say, adding that the rising popularity of endovascular repair may put patients at risk of overtreatment.

There also may be other less tangible harms associated with screening, the editorial notes: “Patients are playing an increasing role in health care decisions and often value outcomes differently than physicians or investigators. The psychological effects of being ‘labeled’ with having an AAA that will not be repaired immediately (if at all) have not been fully explored, but at least 2 [randomized controlled trials] have shown negative psychological effects from diagnosis of small AAAs.”

In an e-mail communication with TCTMD, Dr. Shreibati stood by the need for screening. “The United States Preventative Services Task Force has designated AAA screening for selected populations a Grade B recommendation,” she stressed. “It has been shown to be cost-effective and, though the absolute rates of AAA-related mortality reduction are small, I do believe that this screening is important and justified.”

The risks and benefits of any screening modality deserve periodic reevaluation, she added, “especially when the treatment (such as the surgical repair of AAA) changes over time. AAA screening is a relatively low-cost evaluation with potentially life-saving benefit, but, with any decision to screen nowadays, there may be associated harm related to subsequent evaluation and treatment.

For many, but not all, patients, the benefit outweighs the risk,” Dr. Shreibati concluded.

 

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Sources:
1. Shreibati JB, Baker LC, Hlatky MA, Mell MW. Impact of the Screening Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act on abdominal ultrasonography use among Medicare beneficiaries. Arch Intern Med. 2012;Epub ahead of print.

2. Harris R, Sheridan S, Kinsinger L. Time to rethink screening for abdominal aortic aneurysm?  Arch Intern Med. 2012;Epub ahead of print.

 

 

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