Clinical Risk > Volume 14, Number 6 > Pp. 207

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Editorial

Screening for abdominal aortic aneurysms

Harvey Marcovitch

Email: h.marcovitch{at}btinternet.com

This month, vascular surgeon Hany Hafez outlines the new national screening programme for abdominal aortic aneurysm (AAA) due to start soon with complete coverage of England & Wales by 2013. Scotland starts in 2011. In an accompanying paper, Tracey Elliott, barrister and lecturer at Queen Mary University of London, outlines some of the legal issues that might arise.

Misunderstanding the nature of population screening is common, with some doctors bruised by their encounters with the Courts in trying to explain that screening is not an individual diagnostic process but rather an attempt to categorize a population into those at high risk and those at low risk of a particular disorder. Problems arise around the boundaries of risk or, in other words, how many false-negative and false-positive results are tolerable within an agreed standard of care.

The principles of screening include¹:

• the condition should be an important health problem;
  
• facilities for diagnosis and effective treatment are available;
  
• an acceptable (i.e. minimally invasive) test should be used;
  
• the cost should not be excessive;
  
• adverse effects should be minimal.
  

Adverse effects can include the stress or anxiety caused by false positives and the occasional difficulty of explaining the uncertainties of certain abnormalities, as well as the risk of unnecessary investigation or treatment. Screening for the untreatable may serve to do little except increase distress while a false sense of security provoked by a false-negative result may delay eventual diagnosis if the patient then ignores ‘red light’ signals of disease.² Added to this might be the problems for NHS Trusts and individual clinicians of litigation.

Examples abound. Screening for congenital hip dislocation in the newborn is a common ground for litigation, unsurprisingly when one realizes that, nationally, the screening programme may fail to pick up 30–50% of cases that eventually come to light. It is arguable (and frequently argued) as to how much this reflects poor technique by under-trained examiners and how often the condition is undiagnosable at a certain point even if it is subsequently found to be present.³

Prostate screening has been mooted but not taken up in the UK, probably because there is no robust trial evidence that screening is effective, let alone cost-effective.⁴

AAA screening avoids many of these pitfalls. The placebo controlled MASS trial,⁵ referred to by Mr Hafez, involved 67,800 men aged 65–74 years; over four years there were 47 fewer deaths from AAA than in the control group, albeit the extra cost was £2.2 million. That equates to about £63 per patient (at 2002 prices) and a cost per quality-adjusted life year gained of £36,000, falling to about £8000 per life year gained after 10 years – well within government guidelines for the cost-effectiveness of a screening programme.

AAA screening will reveal a population of elderly men at risk of death from a ruptured aneurysm. They will be offered elective surgery, which is much safer than emergency surgery at the time of rupture or, if the lesion is small, regular follow-up scans. But even elective surgery carries a significant mortality which has to be set against the lives saved. In her paper, Ms Elliott details potential problem areas which can arise from errors in relation to ultrasound interpretation, issues around provision of information and obtaining informed consent and structural failures which could lead to failure to monitor, re-call and re-scan patients.

There are, it seems, always new medicolegal opportunities with every apparent advance.⁶

	Footnotes

 
Harvey Marcovitch FRCP Hon FRCPCH, Editor in Chief of Clinical Risk, Royal Society of Medicine Press, 1 Wimpole Street, London W1G 0AE, UK

	References

Top References

 

1. UK National Screening Committee. Criteria for appraising the viability, effectiveness and appropriateness of a screening programme. See http://www.nsc.nhs.uk/pdfs/criteria.pdf (last checked 31 October 2008)
2. Stewart Brown S, Farmer A. Screening could seriously damage your health. Decisions to screen must take account of the social and psychological costs. BMJ 1997; 314: 533–4[Free Full Text]
3. Dunn P. Congenital dislocation of the hip(CDH): liability for failure to diagnose early. Clinical Risk 2004; 10: 2–4[Free Full Text]
4. Ilic D, O'Connor D, Green S, Wilt T. Screening for prostate cancer. Cochrane Database of Systematic Reviews 2006, Issue 3, Art. No.: CD004720. See http://www.cochrane.org/reviews/en/ab004720.html (last checked 31 October 2008)
5. Ashton HA, Buxton MJ, Day NE, et al. Multicentre Aneurysm Screening Study Group. The multicentre aneurysm screening study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial. Lancet 2002; 360: 1531–9[Medline]
6. Field S. Breast screening issues (a study into funding, staffing, litigation and morale in the NHS Breast Screening Programme). Newsletter of the Royal College of Radiologists 1998; 54: 1–4

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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Marcovitch, H. Search for Related Content Social Bookmarking                      What's this?