Approximately 6000 men die every year from ruptured abdominal aortic aneurysm in England and Wales. Randomised clinical trials and a large pilot study have shown that ultrasound screening of men aged 65 years can prevent about half of these deaths. However, there is a significant perioperative morbidity and mortality from interventions to repair the detected aneurysm. This paper explores the ethical issues of screening men for abdominal aortic aneurysm. It is concluded that a population screening programme for abdominal aortic aneurysm offers a clear balance of good over harm. It is therefore ethically justified, as long as men are given adequate information at every stage of the process. Each man has the right to be properly informed, regardless of whether he accepts the invitation to be screened and, if an aneurysm is detected, whether or not he accepts treatment.
- Medical screening
- aortic aneurysm
- aneurysm screening
- screening ethics
- ethics committees/consultation
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- Medical screening
- aortic aneurysm
- aneurysm screening
- screening ethics
- ethics committees/consultation
Since 1947 the NHS has been responsible mainly for disease management. Repeatedly, medical commentators and, indeed, politicians have observed that too little time and money is spent on disease prevention. In response to the suggestion that prevention is obviously better than attempting to cure, there is a current political and medical focus on screening for a variety of common medical disorders. Screening involves the use of a test to identify a potential medical problem in an otherwise asymptomatic individual. A positive screen raises the potential to avoid the consequences of a disease process, or at least the option of treatment at an earlier stage.
On the face of it, the ethics of disease management are reasonably straightforward. A patient has the opportunity to discuss a course or courses of action and select a treatment, or nothing at all. However, the ethics become more complex once we scratch below the surface of the requirement that the patient is put in a position to make an informed choice. As O'Neill has rightly remarked, consent does not necessarily become better informed as patient information sheets become ever longer and more detailed.1 2
When we turn to the ethics of screening, these difficulties are, if anything, accentuated. Unlike the treatment offered to a patient, the screening test is offered to an individual who is otherwise well; indeed, few people who attend screening expect to receive a diagnosis—most are expecting reassurance. For this reason, the ethics of screening place a particular burden on the quality and content of information given to individuals before they choose whether or not to accept the test. Recent concerns over breast screening have highlighted the risks of under-informing subjects before testing, but merely providing more information is not the answer. Not only do individuals display varying degrees of ability and inclination to assimilate information and comprehend the risks, but there can be complications that stem from a lack of fluency, intellect or linguistic competence. Moreover, as our understanding about the subtler issues of screening develops, the complexity of communication and comprehension is intensified. It is a mistake, as Manson and O'Neill have argued, to think of informing others as simply akin to transferring data from one container to another.3
Screening for abdominal aortic aneurysm
Screening for abdominal aortic aneurysm (AAA) is the latest condition to be funded by the NHS in the UK. Strikingly, it is the first funded programme that has the certain potential to result in the death of an otherwise well individual. There is a risk of about one in 10 000 that a man may attend for a screening ultrasound scan, have the condition diagnosed, be offered an intervention to prevent aneurysm rupture, but then die due to a perioperative complication. If AAA screening is not to be condemned as unnecessarily killing healthy people, it must be scientifically justified and ethically sound.
AAA, which particularly affects elderly men, is a degenerative condition of the abdominal aorta with similar aetiology to coronary heart disease; risk factors include raised cholesterol, hypertension, smoking and family history. AAA rupture is a catastrophic event that usually results in death. It is well established that an AAA that is <5.5 cm in diameter seldom ruptures; the risks of treatment at this stage outweigh the risks of rupture.4 Above 5.5 cm and as the diameter increases, the risk of rupture escalates accordingly. This risk can be almost completely eliminated by an open surgical procedure to replace the aorta with a Dacron graft or, increasingly, by endovascular (keyhole) treatment with a covered stent. These procedures carry a risk of perioperative mortality of 1–7% (mean 4.6% on the UK National Vascular Database at the time of writing; http://www.nvdonline.co.uk/). There is also a significant convalescence, particularly for open surgery, the risk of minor complications and the certainty of scarring; however, quality of life returns to normal within 6–12 weeks of intervention.
While AAA is rare before the age of 60 years, 4% of men aged 65 years have an enlarged aorta (defined as maximum transverse diameter >3 cm). In many respects AAA is ideal for screening since the degenerative process is relatively slow, the diagnosis is easily and reliably made by ultrasound imaging and the natural history of the condition is well studied. After their scan, 96% of 65-year-old men can be reassured and discharged with a normal aorta and a very low risk of aortic rupture.5
In carefully designed randomised controlled trials it has been well established that AAA screening in men aged 65–74 years is effective and decreases the risk of aneurysm rupture by almost 50%. In this group, after a single scan, death from aortic rupture is rare within 10 years and appears reduced for life.6 A small number of men in their late 80s will still die from aortic rupture following a normal scan at 65 years of age, but they do not get the disease at a stage in life when an essentially preventive procedure is indicated. It is explicit that the NHS programme will not eliminate deaths from AAA rupture but, when fully operational, it is expected to make a significant impact on the death rate. The cost/benefit analysis of AAA screening is taken from the 10-year follow-up of the largest randomised trial (MASS trial). Costs were £7600 (95% CI £5100 to £13000) per life year gained and are expected to improve with time from screening.6 These fall within accepted cost ratios for interventions as defined by the National Institute for Health and Clinical Excellence in the UK.
Few of the 4% of 65-year-old men with an enlarged aorta at their initial scan have an AAA large enough to warrant intervention. Yet progressive enlargement of the aorta with time can be monitored by regular ultrasound surveillance and intervention offered once the AAA enlarges above 5.5 cm in diameter. In fact, death from cardiorespiratory disease is more common in this cohort of men who are a ripe target for additional preventive strategies such as statins, antiplatelet and antihypertensive treatment. The NHS AAA Screening Programme, it should be noted, includes nurse-led lifestyle advice to men diagnosed with an AAA. A calculation based on the MASS study suggests that 191 men need to be invited (based on 80% uptake) to prevent one ruptured AAA over the subsequent 10 years (S Thompson and A Scott, personal communication).
Critics of screening suggest that the current mortality rate after elective AAA repair in the UK is too high for a national programme to be supported. They also claim that, for some men, the knowledge that they are living with a small AAA (time bomb) under surveillance is intolerable and affects their quality of life.7 A Quality Improvement Programme led by vascular specialists in the UK has provided the framework for management that is expected to halve the elective mortality rate by 2013, when it is planned that the roll out of screening will be completed in England. Part of this involves remodelling vascular services to agreed standards (a positive benefit of the introduction of AAA screening). One of the ways to improve mortality is to expand the availability of endovascular treatment which has a 30-day mortality rate of around 1%, lower than open AAA surgery.8
Ethics of AAA screening
There are several ethical questions concerning AAA screening, starting with the background justification for the programme—essentially, the question of whether the adoption of a publicly-funded and NHS-backed AAA screening programme is justified—and then running through the implementation and operation of the programme, including questions about the information to be given to prospective participants.
Given that these various ethical questions relate to different phases of the programme, some might argue that we need to be careful about the way in which the particular question is characterised: is it one that is governed by ‘public health ethics’ or is it one that falls to be debated as a matter of ‘medical ethics’? For example, some might argue that, when questions concern the background justification for the adoption of the programme, we should draw on public health ethics while, when questions focus on the treatment of a person whose scan discloses an AAA (such that they now find themselves in the position of a patient rather than that of a screening participant), it is medical ethics that should guide us. Subject to two (similar) caveats, we have no objection to this way of presenting the matter. The first caveat is that we should not assume that the designation of a question as one of public health necessarily licenses (even less, compels) the use of utilitarian ethics; and the second caveat is that the Georgetown principles (of respect for autonomy, beneficence, non-maleficence and fairness)9 should not be seen as the only plausible account of medical ethics. Indeed, whenever there is a challenge to the ethics of the AAA screening programme (and no matter what the focal point of the challenge), the critical question is whether the practice or action is rights-compatible. For instance, the invitation to be screened goes to men who have a right of self-determination: is this right respected? Men who submit to screening have a right to their physical integrity: is this right respected? There is a right to fair processing of personal data: is it respected? Health-related information is private and confidential: is the privacy and confidentiality of participants' information respected? It is these—and similar rights-focused questions—that should be central to deliberations about the ethics of AAA screening.
The background ethical question is whether the introduction of the AAA screening programme can be justified. On the positive side, it can reasonably be expected that the programme will play a part in reducing and preventing the number of deaths from sudden aortic rupture, particularly for men in their 60s and 70s who (with screening) can be assisted to continue to lead fulfilling and active lives, contributing to their families and to the larger community. On the negative side, there is the concern that some of those whose screening results are positive will experience psychological distress (knowing that they are at risk), and the probability that some of those who elect to undergo corrective procedures will die prematurely as a result of the failure of those procedures.
Before considering whether, in such a context of anticipated benefit and risk, it is ethically justifiable to introduce AAA screening, we should set aside a question about the possible unfairness of this programme. Namely, is it fair that AAA screening should be introduced for men but not for women? While approximately 6000 men die each year from ruptured AAA (although figures taken from national statistics on the cause of death are notoriously inaccurate in this group), the incidence of AAA in women is much lower (male:female ratio 8:1) and women tend to be older at the time of rupture. This lower incidence and different age pattern means that screening is neither a clinical priority nor cost-effective in women.10 Single sex screening programmes are not uncommon (such is the case, for example, with breast screening); discrimination and triage in healthcare are not in themselves problematic. There is no reason to single out AAA screening on this particular ground as a target for ethical criticism.
To return to the background concern that the AAA screening programme will channel some otherwise well persons towards a premature death, how can we justify this initiative? Notwithstanding the first of the above caveats, the fact of the matter is that much preventive and public health thinking is underwritten by a utilitarian ethic. Applying such an ethic, provided that a screening policy maximises welfare, it is justifiable. Inevitably there will be questions about how the utilitarian metric compares and computes, on the one side, the quality of different lives and, on the other, various degrees of distress, as well as the tragedy of some deaths. However, this is no longer the principal reason for treading carefully with utilitarianism. Rather, it is that the UK, along with many other communities, has made a public (politicolegal) commitment to respect for human rights. In these communities, Benthamite ethics have given way to an ethic that prioritises the rights of individual persons, whether patients or other kinds of participants in healthcare settings. Reflecting this displacement of utilitarianism, Article 2(d) of the UNESCO Universal Declaration on Bioethics and Human Rights (2005) announces that one of its aims is ‘to recognise the importance of freedom of scientific research and the benefits derived from scientific and technological developments, while stressing the need for such research and development to occur within the framework of ethical principles set out in this Declaration and to respect human dignity, human rights and fundamental freedoms’. Article 3(1) duly expresses the principle that ‘[h]uman dignity, human rights and fundamental freedoms are to be fully respected’ and Article 3(2) emphasises that ‘[t]he interests and welfare of the individual should have priority over the sole interest of science or society’. Stated briefly, this ruling ethic demands that, in both research and clinical settings, participants and patients should be respected as rights-holding agents and, critically, that the actions of researchers and clinicians should be authorised by relevant informed consents. Although, as we have said, there is some complexity in carrying over this kind of analysis to screening procedures, the governing principles remain constant.
Yet, is this not too quick in forgetting that the background question concerns a measure of public health? Where public health is the context, is there not some residual room for utilitarian ethics? When there is a public health emergency, rights-infringing measures might be justified even though the parties who are affected have not given their informed consent. For example, the compulsory isolation of a dangerous disease carrier might be a justified protective measure. However, this is not necessarily an opening for the rehabilitation of utilitarianism, for such measures might be justified within a framework of rights-thinking (by reliance on overriding and more compelling rights) or by virtue of some exceptional (non-utilitarian) stewardship competence (as advocated by the Nuffield Council on Bioethics).11 12 In neither case do these covering ethics reduce to utilitarian reasoning and, in any case, AAA screening is hardly a response to an emergency.
Simply to offer screening for AAA does not obviously infringe any rights. No doubt there will be different views about the best use of NHS resources, but proposals for screening are subjected to careful scrutiny and the threshold for adoption is high. If anything, the more likely complaint will be that screening is not available for a particular condition. Accordingly, once utilitarian calculations are set aside, the answers to the ethical questions hinge on the rights of the men who are invited to undergo AAA screening, the information that they have received and whatever consents they have given. In turn, we need to focus on the two stages of the process: first, the decision whether or not to submit to screening; and, second, where the test shows a significantly enlarged aorta, the decision as to treatment. At both stages the individual has a right to be informed and, importantly, this right holds irrespective of the decision that is eventually made (to submit or not to screening, and to take up or not a proposed treatment option). In other words, the process of informing a prospectively self-determining individual needs to satisfy ethical requirements for informed non-submission as much as for an informed consent to screening and treatment.13
Where a publicly-sponsored screening programme is offered, the State (and its agents) has a responsibility to ensure that invited participants have a sufficient understanding of both the risks and the benefits. How can we ensure that 65-year-old men who are invited to undergo AAA screening do so in a context that is properly informed? Translating this informational responsibility into a defensible, workable and non-counterproductive practice is far from straightforward. On the one hand, the way in which the information is framed can make a good deal of difference to the way in which it is apprehended. On the other hand, the biases and predispositions of individual recipients of the information can affect the way in which it is acted upon.14 The duty to inform, like the right to be informed, is not susceptible to mechanical articulation and application.
Even if recipients have a reasonable understanding of the benefits of the screening (for themselves and for others), how can we be sure that they fully appreciate the risks? In particular, how can the risk that there might be difficult decisions ahead be communicated? How can we caution against the distress that might be experienced if the test (unexpectedly) reveals an AAA? For, if these men decide not to undergo treatment, they now know that they are ‘at risk’ (and living under a death threat of which they were previously blissfully unaware) and, if they opt for treatment, they risk being one of the unlucky ones who fail to survive the procedure. The obvious way of informing these men is by emphasising that screening is optional, that screening might disclose a condition that needs treatment, that treatment is not always successful and that (paradoxically) there is a right not to undergo screening—a right recognised, for example, in Article 10(2) of the Convention on Human Rights and Biomedicine. Of course, by spelling out the risk in this way, the screening programme might be less well subscribed than it would have been and some men who opt against screening might die when their lives could have been extended. This is an outcome that will have little appeal either for utilitarians or for followers of the Georgetown principles, the former reasoning that this is wasteful and the latter that this is a case where autonomy should yield to beneficence. However, a commitment to rights implies a willingness to forego overall utility and, although we must regret the loss of lives that could have been saved, there is no guarantee that a rights ethic steers individuals towards making optimal life and death decisions.
Where an individual, having been fully informed, is screened and where the test result is positive, that person is now in much the same situation as a patient who is informed about various treatment options. Where such persons decline to be treated, healthcare professionals might judge that this is a poor choice, and let us suppose that the evidence supports this by suggesting that more lives would be saved than would be lost if the treatment were to be given. Again, it is tempting to recur to utilitarianism or to the value of beneficence, or even to old-fashioned paternalism. However, the ethic of rights is driven by different considerations: quite simply, so long as we are dealing with a competent human being, the choices that an individual makes in relation to his or her own healthcare are for that individual—and for that individual alone.
In the light of these remarks, it is clear that there is a robust response to those who object that the NHS screening programme for AAA is unethical in that it serves to herd healthy people towards an early demise. Where individuals make their own informed choices, the only ones who end up in early graves are those who make choices that take them there. Nevertheless, there are two more subtle concerns with the AAA screening programme that might trouble rights-thinkers.
The first concern is that the AAA screening programme is a publicly-funded initiative. It comes only after careful consideration of its acceptability and prospective benefit; as such, it comes with the imprimatur of the State. It does not follow from this that 65-year-old men will submit to screening in an unreflective manner; no doubt some invitations will end up in the rubbish bin along with other unsolicited mail. However, to assuage rights theorists, it is important that, at all stages, it is recognised that the public health system is engaging with rights-bearing individuals. Accordingly, given the right to self-determination, it needs to be made unequivocally clear from the outset that submission to AAA screening is entirely at the option of the man.
The second concern is with the general trajectory of healthcare policy, a policy for which the AAA screening programme is a standard bearer. Arguably, in most cases prevention is better than cure and, as a recent report from the Nuffield Council on Bioethics highlights, there are significant preventive strategies for dealing with public health issues such as obesity and alcoholism.14 However, in a community with liberal commitments, such strategies need to respect the individual's right to make his or her own healthcare choices: preventive intervention can infringe rights as well as leading to unintended negative consequences. That said, with a growing pressure on healthcare budgets, it is tempting to couple the discourse of prevention with renewed reminders about the responsibilities of individuals for their own health and well-being. In a culture that has these characteristics, rather than opting in to an AAA screening programme, 65-year-old men would find that the default (a default backed by the sense of responsibility) is to have the test. Granted, there might still be the paper option of opting out, but in reality it would be only those with strong convictions who would take this option. The danger, ethicists might argue, is not so much that consent is not fully informed but that the ‘regulatory environment’ has changed in a way that the decision to submit to screening is no longer a free one.15
It is axiomatic that healthcare initiatives such as the NHS screening programme for AAA should not harm participants. When the programme incurs casualties, some might question its ethical credentials. The way to respond, however, is not by appealing to a utilitarian calculation that claims that the programme shows a clear balance of good over harm. Rather, in a community of rights, the defence of the programme must rest on the free and informed decisions made by those who are invited to participate. So long as we do our best to ensure that those decisions are free and properly informed—which, admittedly, is far from a formality—there is no need for an ethical apology.
The authors thank the Advisory Group of the NHS Abdominal Aortic Aneurysm Screening Programme and Alan Scott and Simon Thompson for their helpful comments.
A copy of the information given to men on invitation can be found on the screening website(http://aaa.screening.nhs.uk).
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.
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