Screening Prevents Aneurysm Deaths, But Questions Remain Over Cost Effectiveness

Main Category: Cardiovascular / Cardiology
Article Date: 29 Jun 2009 - 1:00 PDT

email to a friend   printer friendly   view / write opinions   rate article

The national aortic screening programme in the UK should, in due course, prevent about half of all aneurysm deaths in men over 65 and will be extremely cost effective for the NHS, conclude researchers in a study published on bmj.com. However a second study, also published today, concludes that screening is not cost effective and calls for additional research into the long term outcomes and costs of screening.

Every year in England and Wales about 6,000 men die from a ruptured aortic aneurysm (caused by ballooning of the artery wall), but abdominal aortic aneurysms can be detected with a one-off ultrasound scan. A national screening programme for men aged 65 began in the UK in spring 2009.

In the first study, Simon Thompson from the Medical Research Council and colleagues report 10 year mortality data from The UK Multicentre Aneurysm Screening Study (MASS) involving 67,770 aged 65-74 randomised to be invited to ultrasound screening or not. They also calculated the long term cost effectiveness of the programme in the UK.

Results showed that over 10 years there were about half as many abdominal aortic aneurysm deaths (155) in the invited group compared to the control group (296). The benefit of being invited to screening shown in the early years of follow-up was maintained in later years - reductions in abdominal aortic aneurysm mortality were estimated as 42% at four years, 47% at seven years, and 48% at 10 years.

Further analysis showed that the cost effectiveness of screening became greater over time, with cost per life year gained improving from an estimated £41,000 after four years, £14,000 after seven years, and £7,600 after 10 years. The estimate after 10 years is well below the guideline figure of around £25,000 per life year gained for the acceptance of medical technologies and interventions in the NHS, say the authors.

They conclude that the UK national screening programme for abdominal aortic aneurysm should, in the long term, halve the mortality rate related to abdominal aortic aneurysm in men aged 65 or more, and that it will be a cost effective programme for the NHS."

But in a second study, researchers argue that aneurysm screening is not cost effective. Lars Ehlers from Aarhus University and colleagues used a recognised mathematical model, alongside data from published studies and the Danish Vascular Registry, to calculate expected costs and health outcomes for a hypothetical population of Danish men aged 65 from screening to death.

The estimated cost of screening per quality adjusted life year (QALY - a combined measure of quantity and quality of life) was £43,485. At a willingness to pay threshold of £30,000 the probability of screening being cost effective was less than 30%, say the authors.

"Our estimate is not comparable with previous modelling studies, which in general claim that screening for abdominal aortic aneurysm is cost effective," they write. "We believe our study provides a more realistic estimate of cost effectiveness."

From the evidence in these two papers, it is hard to identify the reasons for the differing findings without further detailed exploration of the models used, says Professor Martin Buxton in an accompanying editorial.

However, the accumulated evidence suggests that a national screening programme in the UK is appropriate and likely to be cost effective, but its costs and outcomes need to be carefully monitored and the data need to be regularly re-analysed to ensure that both the effectiveness and cost effectiveness remain acceptable in the context of changing practice, he concludes.

"Research: Screening men for abdominal aortic aneurysm: 10 year mortality and cost effectiveness results from the randomised Multicentre Aneurysm Screening Study", BMJ online

"Research: Analysis of cost effectiveness of screening Danish men aged 65 for abdominal aortic aneurysm", BMJ online

"Editorial: Screening for abdominal aortic aneurysm", BMJ online

Source
British Medical Journal