conflicting cost-effectiveness results for aaa screening

PharmacoEconomics & Outcomes News 582 - 11 Jul 2009

Conflicting cost-effectivenessresults for AAA screening

The cost-effectiveness of screening men forabdominal aortic aneurysm (AAA) has been evaluated intwo studies published in the BMJ, with conflictingresults.1,2

It pays in the UKResearchers from the Multicentre Aneurysm

Screening Study (MASS) suggest that screening for AAAin men aged 65-74 years would be cost effective.1

In MASS, 33 883 such men were randomised to thescreening group (27 204 attended the initial scan) and33 887 to a control group. Of the 1334 aneurysms(≥ 3.0cm in diameter) detected by screening, those sized3.0–4.4 cm were scheduled for annual scans, and thosesized 4.5–5.4cm for 3-monthly scans; larger, rapidlygrowing or symptomatic aneurysms were referred for asurgical review. Cost-effectiveness was determinedusing the MASS 10-year data and UK national data, froma UK health service perspective; costs were converted toreflect 2008-9 prices.

Overall, there were 155 deaths associated with AAAsin the screening group, compared with 296 in thecontrol group; this equated to a significant 48%reduction in relative risk. Although the cost per personwere greater by an average of £100 with screening, thefewer deaths led to an incremental cost-effectivenessratio (ICER) of £7600 per life year gained.

The researchers concluded that their result "is wellbelow the guideline figure of around £25 000 per lifeyear gained for the acceptance of medical technologiesand interventions in the NHS."

Danes disagreeHowever, researchers from Denmark found that

screening for AAA was not cost-effective in a similaranalysis.2

They utilised a decision tree and Markov model toassess the cost effectiveness of screening and notscreening for AAA in a cohort of men aged 65 years,from a health care perspective. Data from MASS, theDanish Vascular Registry, and other Danish nationalsources were incorporated; costs were in 2007 prices.

Overall, the ICER for the base case was £43 485 perQALY; one-way sensitivity analyses with a 30% and a50% probability of reaching hospital alive with ruptureresulted in ICERs of £32 640 per QALY and £66 001 perQALY, respectively. The chance of screening being costeffective was < 30% at a willingness-to-pay threshold of£30 000.

Screening for AAA A-OK?In an accompanying editorial, Professor Martin J

Buxton from Brunel University, Uxbridge, UK,considered the results from both studies, but contendsthat "the accumulated evidence suggests that a nationalscreening programme in the UK is appropriate and likelyto be cost effective", although ongoing monitoring isrequired.3

1. Thompson SG, et al. Screening men for abdominal aortic aneurysm: 10 yearmortality and cost effectiveness results from the randomised MulticentreAneurysm Screening Study. BMJ 338: 1538-1541, No. 7710, 27 Jun 2009.

2. Ehlers L, et al. Analysis of cost effectiveness of screening Danish men aged 65for abdominal aortic aneurysm. BMJ 338: 1542-1544, No. 7710, 27 Jun 2009.

3. Buxton MJ. Screening for abdominal aortic aneurysm. BMJ 338: 1509-1510,No. 7710, 27 Jun 2009.

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PharmacoEconomics & Outcomes News 11 Jul 2009 No. 5821173-5503/10/0582-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved