Should we screen women for abdominal aortic aneurysm?
Authors: Minna Johansson, Karsten Juhl Jørgensen
Journal: The Lancet (2018)

In The Lancet, Michael Sweeting and colleagues1Sweeting J Masconi KL Jones E et al.Analysis of clinical benefit, harms, and cost-effectiveness of screening women for abdominal aortic aneurysm.Lancet. 2018; (published online July 26.)http://dx.doi.org/10.1016/S0140-6736(18)31222-4Summary Full Text Full Text PDF PubMed Scopus (41) Google Scholar report their estimate of the benefits, harms, and cost-effectiveness of screening women for abdominal aortic aneurysm (AAA) based upon their modelling study. A discrete event simulation model was set up and women-specific parameters were obtained from systematic literature reviews, national registry or administrative databases, major AAA surgery trials, and UK National Health Service reference costs. By use of the same screening strategy as used for men (age 65 years; 3·0 cm cutoff for diagnosis; 5·5 cm cutoff for surgery), there were three fewer AAA-related deaths, ten women overdiagnosed with AAA, and one woman overtreated for AAA per 10 000 invited over a 30-year period. For every four women who avoided an AAA-related death, one died because of additional elective repair as an outcome of screening. The authors conclude that this screening is not cost-effective. In the authors' best-alternative strategy (including women aged 70 years; 2·5 cm cutoff for diagnosis; 5·0 cm cutoff for surgery), screening resulted in six fewer AAA-related deaths, 67 women overdiagnosed with AAA, and five women overtreated for AAA for every 10 000 women invited over a 30-year period. For every seven women who avoided an AAA-related death, two died because of additional elective repair as an outcome of screening. It is unusual for cost-effectiveness analyses of screening to include overdiagnosis and overtreatment. This study is therefore an important step forward. However, there was considerable uncertainty regarding the cost-effectiveness (incremental cost-effectiveness ratio of £23 000 per quality-adjusted life-year [QALY] for the best-alternative strategy; 95% CI 9500–71 000), mainly because of assumptions about AAA prevalence, distribution of aortic size at different ages, and effects on quality of life. Sensitivity analyses showed that a negative effect on quality of life as a result of diagnosis, including overdiagnosis, would substantially reduce cost-effectiveness. This association has been poorly investigated for most screening programmes. Therefore, this finding could challenge the continued justification of screening for many other diseases,2DeFrank JT Barclay C Sheridan S et al.The psychological harms of screening: the evidence we have versus the evidence we need.J Gen Intern Med. 2015; 30: 242-248Crossref PubMed Scopus (45) Google Scholar making the effects of screening on quality of life a high-priority research area. Assumptions about future reductions in disease prevalence also substantially reduced cost-effectiveness. Previous studies have shown decreasing AAA-related mortality in women from the mid-1990s to 2009.3Anjum A Powell JT Is the incidence of abdominal aortic aneurysm declining in the 21st century? Mortality and hospital admissions for England & Wales and Scotland.Eur J Vasc Endovasc Surg. 2012; 43: 161-166Summary Full Text Full Text PDF PubMed Scopus (96) Google Scholar In 1974, 41% of UK women smoked compared with 17% in 2014,4Office for National StatisticsAdult smoking habits in Great Britain.https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/drugusealcoholandsmoking/datasets/adultsmokinghabitsingreatbritainDate: 2017Date accessed: July 13, 2018Google Scholar and since the correlation between smoking and AAA is stronger in women than in men, AAA-related mortality is likely to continue to decrease for women, reducing the need for screening. Apart from concerns about cost-effectiveness, there are ethical dilemmas associated with the use of AAA screening. That the health-care system causes the death of healthy citizens by inviting them to an intervention that they have not asked for is ethically problematic. It is not as simple as a matter of net benefit in terms of mortality because it is not clear that a death saved by screening equals out a death caused by screening—such strict utilitarianism is hardly acceptable. Furthermore, there are other important harms. The best-alternative strategy in the study by Sweeting and colleagues resulted in a 55% increase in women who fulfilled criteria for elective surgery for AAA but had contraindications. They were told that they have a condition that could cause death at any minute but that nothing can be done for them since any elective procedure would be too risky. Elective surgery for AAA has serious complications such as myocardial infarction, stroke, amputation, respiratory failure, renal failure, ischaemic colitis, spinal cord ischaemia, and prosthetic graft infections.5Calonge N Screening for abdominal aortic aneurysm, recommendation statement. US Preventive Services Taskforce.http://www.uspreventiveservicestaskforce.org/uspstf05/aaascr/aaars.pdfDate: 2005Date accessed: July 13, 2018Google Scholar, 6Linné A Smidfelt K Langenskiöld M et al.Low post-operative mortality after surgery on patients with screening-detected abdominal aortic aneurysms: a Swedvasc registry study.Eur J Vasc Endovasc Surg. 2014; 48: 649-656Summary Full Text Full Text PDF PubMed Scopus (11) Google Scholar Screening results in a large increase in elective surgeries during the first 10 years after screening, but much of the benefit occurs 10–30 years later. Unfortunately, complications to surgery were not included in the present analysis. A recent study on endovascular repair for thoracic aneurysm7Perera AH Rudarakanchana N Monzon L et al.Cerebral embolization, silent cerebral infarction and neurocognitive decline after thoracic endovascular aortic repair.Br J Surg. 2018; 105: 366-378Crossref PubMed Scopus (39) Google Scholar showed that cerebral embolisms occur with 80% of surgeries, affecting cognitive function. There has been no similar study for AAA surgery. Clearly, repair of thoracic aneurysms is likely to infer a substantially higher risk for cerebral embolism than AAA surgery; however, future studies should explore how AAA surgery affects cognition and how many patients return to an independent life. The authors suggest a lower threshold for diagnosis and for elective surgery in women on the basis of biological features. However, there is no evidence for this claim and there are potential harms.8Johansson M Harris RP Thresholds in women with abdominal aortic aneurysm.Lancet. 2017; 389: 2446-2448Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar, 9Ulug P Sweeting MJ von Allmen RS et al.Morphological suitability for endovascular repair, non-intervention rates, and operative mortality in women and men assessed for intact abdominal aortic aneurysm repair: systematic reviews with meta-analysis.Lancet. 2017; 389: 2482-2491Summary Full Text Full Text PDF PubMed Scopus (100) Google Scholar Actually, the study by Sweeting and colleagues suggests that lowered thresholds for the diagnosis and for elective surgery in women might result in a less favourable benefit–harm balance because of substantial increases in overdiagnosis and overtreatment. Screening requires skilled human resources and occupies operation theatres and hospital beds. These opportunity costs might, for example, increase waiting time for other types of surgery, such as for cancer surgery. Indeed, considering the small estimated average benefit from screening women for AAA (0·00112 QALYs,1Sweeting J Masconi KL Jones E et al.Analysis of clinical benefit, harms, and cost-effectiveness of screening women for abdominal aortic aneurysm.Lancet. 2018; (published online July 26.)http://dx.doi.org/10.1016/S0140-6736(18)31222-4Summary Full Text Full Text PDF PubMed Scopus (41) Google Scholar equivalent to 9·8 h per invited woman), the net effect may be negative from a public health perspective. This study indicates that screening women for AAA is not economically acceptable. The benefit–harm balance might also be ethically questionable, but this remains a value judgment. Furthermore, this study points to an urgent need for cost-effectiveness analyses for current AAA screening programmes for men that take into account both the large declines in AAA-related mortality and harms of screening such as overdiagnosis, overtreatment, and effects on quality of life.10Johansson M Zahl PH Siersma V Jørgensen KJ Marklund B Brodersen J Benefits and harms of screening men for abdominal aortic aneurysm in Sweden: a registry-based cohort study.Lancet. 2018; 391: 2441-2447Summary Full Text Full Text PDF PubMed Scopus (39) Google Scholar We declare no competing interests. Analysis of clinical benefit, harms, and cost-effectiveness of screening women for abdominal aortic aneurysmBy UK standards, an AAA screening programme for women, designed to be similar to that used to screen men, is unlikely to be cost-effective. Further research on the aortic diameter distribution in women and potential quality of life decrements associated with screening are needed to assess the full benefits and harms of modified options. Full-Text PDF Open Access