Balancing the evidence for guidelines: lessons from the NICE abdominal aortic aneurysm guidance—an essay by Bruce CampbellBMJ 2020; 370 doi: https://doi.org/10.1136/bmj.m3480 (Published 24 September 2020) Cite this as: BMJ 2020;370:m3480
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We read Professor Campbell’s essay “Balancing the evidence for guidelines: lessons from the NICE abdominal aortic aneurysm guidance” (1) with interest. Professor Campbell argues correctly that “hard evidence” from randomised trials and economic evaluations needs to be balanced with “softer” evidence about patient experiences and preferences when developing guidelines.
Two issues arise from this. Firstly, do we know what patients’ preferences are? Secondly, to what extent should those preferences influence guidance when those preferences may disadvantage other patients within the healthcare community.
In the case of abdominal aortic aneurysm [AAA] and choices for its management, while it is often asserted that patients prefer EVAR because of its lower morbidity and mortality, the evidence supporting this assertion is extremely weak. Professor Campbell cites his 2009 paper (2) as an example of evidence supporting this assertion, though the information supplied to patients in this study specifically excluded the long-term harms associated with EVAR. A recent qualitative evidence synthesis identified only four studies exploring the experiences of patients with AAA (3). Despite many years of technical development in options for the repair of AAA, the voice of the patient remains remarkably absent in the literature and it remains only a “perception… …that EVAR [is] the intervention that many patients prefer”. An alternative assertion is that rates of AAA rupture are overestimated (4) and in many cases patients sensitively informed of the risk of harm from AAA will prefer no intervention.
If arguments about patient preference are made to balance or mitigate “hard” evidence, then these arguments need to be supported by evidence of their own. If we allow poorly evidenced assertions to deny the conclusions of well-designed clinical trials, then there is little point running those trials in the first place.
The second issue is essentially one of whether one takes a largely utilitarian view of healthcare resource distribution (and the necessary choices associated with this) or a more egalitarian view. Each philosophical approach has its benefits and drawbacks and ultimately a judgement needs to be made as to which to favour when practical guidance is being formulated. Professor Campbell cites NICE’s Social Value Judgement document, now superseded by its Principles document (5), which made it extremely clear that NICE favours a utilitarian approach when asking its guideline development committees to interpret evidence and make recommendations. The document explicitly states “…NICE agrees that respect for autonomy and individual choice are important for the NHS and its users, this should not mean that NHS users as a whole are disadvantaged by guidance recommending interventions that are not clinically and/or cost effective.” Similar statements are found in NICE’s updated principles document.
In the specific case of AAA repair, the evidence is clear that EVAR is both more expensive and delivers poorer outcomes for the NHS than open repair (6). Even if a fully informed patient has a preference for EVAR (either in preference to open repair or to no repair), should EVAR be made available when the additional resource used could be used to provide more health elsewhere? NICE’s Social Value Judgement document makes it clear that it should not.
The strength of NICE’s recommendations derives from the transparency and rigour of their development within an agreed philosophical framework. This results in recommendations that sometimes clash with accepted practice. The answer to this dilemma is to provide more high-quality evidence, not to retreat into an intellectual cul-de-sac where assertions carry the same evidential weight as good-quality clinical data and philosophical frameworks are discarded merely because they are inconvenient.
Dr Christopher Hammond.
Consultant vascular radiologist, Leeds. UK
Professor Andrew Bradbury.
Sampson Gamgee Professor of Vascular Surgery, University of Birmingham. Birmingham, UK
Dr Hammond was a member of-, and Professor Bradbury was chairman of- the NICE AAA Guideline Development Committee, 2014-2020
1 Campbell, B. Balancing the evidence for guidelines: lessons from the NICE abdominal aortic aneurysm guidance. BMJ 2020; 370: m3480. http://dx.doi.org/10.1136/bmj.m3480
2 Winterborn RJ, Amin I, Lyratzopoulos G et al. Preferences for endovascular (EVAR) or open surgical repair among patients with abdominal aortic aneurysms under surveillance. Journal of Vascular Surgery 2009; 49, 576 - 581.e3.
3 Duncan R, Essat M, Jones G et al. Systematic review and qualitative evidence synthesis of patient-reported outcome measures for abdominal aortic aneurysm. British Journal of Surgery 2017; 104: 317-27.
4 Parkinson F, Ferguson S, Lewis P et al. Rupture rates of untreated large abdominal aortic aneurysms in patients unfit for elective repair. Journal of Vascular Surgery 2015; 61: 1606 – 1612.
5 NICE: Our principles. Available at: https://www.nice.org.uk/about/who-we-are/our-principles. Accessed 25.09.2020
6 Patel R, Powell JT, Sweeting MJ et al. The UK endovascular aneurysm repair (EVAR) randomised controlled trials: Long-term follow-up and cost-effectiveness analysis. Health technology assessment 2018; 22, 1 – 132.
Competing interests: No competing interests