Repeat AAA Screening in Older Men May Be Cost-Effective

Marlene Busko

July 06, 2012

July 6, 2012 (Odense, Denmark) — A new study based on a predictive model using Danish data confirms that screening men once at age 65 for abdominal aortic aneurysm (AAA) is very cost-effective vs no screening [1]. Among men with enlarged aortic diameters below the threshold for surgery, at least one repeat screening at age 70 appears to also be cost-effective, the researchers add.

The study is published online July 5, 2012 in BMJ.

"Screening for AAA is a highly cost-effective choice when compared with other screening programs, such as colon cancer or cervical cancer, [which] are already implemented in Denmark," lead author Dr Rikke Søgaard (University of Southern Denmark, Odense) told heartwire in an email.

"Our results show that the optimal strategy (again from a rational point of view) depends on how much decision makers are willing to pay per quality-adjusted life-year [QALY]," she added. "If they are willing to pay less than £10 000 [$15 730], say, the screening-once strategy is the most cost-effective, whereas if their threshold is £20 000 [$31 460], the screening-twice strategy is the most cost-effective. Finally, if their threshold is £30 000 [$47 190], they should consider lifetime screening every five years."

Seeking Optimal AAA Screening Strategy

Earlier studies have established that screening men older than 65 years for AAA can reduce mortality. Although England and Scotland have recently implemented national screening programs, Denmark and other European countries have not yet done so.

To help guide national healthcare-policy decisions, the group developed a model to assess the consequences of four screening strategies for AAA in a hypothetical population of 100 000 men:

  • No screening.

  • Screening once at age 65.

  • Screening twice (at age 65 and 70).

  • Screening every five years from age 65.

The model used recent data to estimate how the disease would progress, and costs were estimated in 2010 pounds. In the model, repeat screening was done in men with an aortic diameter of 25 to 29 mm at the initial screening who had a high risk of rupture. Men who already had an aortic diameter of 55 mm or more and no contraindications for surgery received elective surgery.

Screening involves "a simple ultrasound test that can be undertaken within five minutes by a nurse," Søgaard explained. "The test itself costs about £20 [$31.46], but since a screening program leads to more elective surgery and less acute surgery, the total (incremental) cost of screening is higher."

The model predicted that a clinically relevant aneurysm would be found in 2469 men per 100 000 screened.

If high-risk men were rescreened once, five years after their initial test, AAA would be detected in an additional 452 men per 100 000, with an incremental cost of £10 013 per QALY. This falls within the cost-effectiveness threshold of £20 000 [$31 460] set by the UK National Institute for Health and Clinical Excellence.

In contrast, rescreening high-risk men every five years after their initial screening would detect aortic aneurysm in an additional 794 men per 100 000, with an incremental cost of £29 680 per QALY.

Søgaard explained that they looked at men age 65 and older, since 70% of deaths from abdominal aortic aneurysm occur in this population. The group is currently studying aortic-aneurysm prevalence among women, to be able to assess the cost-effectiveness of a similar screening program for women.

American Experience

The study is "not the first to show that screening for abdominal aortic aneurysm is cost-effective," Dr K Craig Kent (University of Wisconsin, Madison) commented to heartwire .

"In the US, we are willing to pay $40 000 to $60 000 per QALY," he wrote. The cost per life-year saved for screening for AAA is $11 285, which falls between that for CABG for left main disease ($9500) and for hemodialysis for end-stage renal disease ($54 400), he added.

Dr Janet T Powell (Imperial College London, UK), also commenting on the study for heartwire , noted that this study provides new information about the cost-effectiveness of following up patients with 2.5- to 2.9-cm aortas, and the multistage/transition model is new. She cautions, however, that "some of the assumptions appear outdated--eg, there are no costs for emergency endovascular repair of ruptured aneurysms, the costs for elective procedures appear very high, the prevalence of aneurysms [is] overestimated for 2012, [and since] rupture rates of small aneurysms are [now] declining by about 4% per year, the rupture rates used may be too high." UK screening measures internal aortic diameters, which are 3 to 6 mm smaller than external diameters, she noted.

The study was funded by the Health Research Fund of Central Denmark Region and the Research Fund of Viborg Hospital.

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