Cost-effectiveness of different screening strategies for abdominal aortic aneurysm

OBJECTIVE: The primary objective of this study was to develop a simulation model to assess the cost-effectiveness of different screening strategies for abdominal aortic aneurysms (AAAs) in men. METHODS: A systematic review of the literature was conducted for different screening strategies in terms of age (60, 65, or 70 years) and risk profiles (all men or specific high-risk groups) of the screened population, and rescreening after 5 or 10 years. These data were analyzed in a Markov simulation cohort model. RESULTS: The cost per life year gained for different screening strategies ranged from US 8,309 dollars to US 14,084 dollars and was estimated at US 10,474 dollars when 65-year-old men were screened once. Screening 60-year-old men was equally cost-effective, with the advantage of more life years gained. We demonstrated a trade-off between high prevalence of AAA and lower life expectancy, eliminating the expected benefits of screening high-risk groups such as smokers (US 10,695 dollars) or cardiovascular patients (US 10,392 dollars). Assuming general population utility resulted in a cost per quality-adjusted life year (QALY) gained of US 13,900 dollars, whereas a hypothetical 5% reduction in utility among men with a screening-detected AAA raised the cost per QALY gained to US 75,100 dollars. CONCLUSION: This Markov model, which was based on a systematic review of the literature, supplied information on the estimated cost-effectiveness of different screening strategies. Screening men for AAA may be cost-effective in the long-term. Different screening strategies and quality-of-life effects related to screening for AAA need to be evaluated in future clinical studies.     

Randomized clinical trial of screening for abdominal aortic aneurysm in women

BACKGROUND: Screening for abdominal aortic aneurysm (AAA) is commonly restricted to men. Recent studies have indicated a possible increase in deaths due to ruptured AAA in women, and a higher rate of rupture in women than in men. The present report details results from a randomized controlled trial that assessed the effects of screening women for AAA. METHODS: Some 9342 women aged 65-80 years were entered into the trial and randomized to age-matched screen and control groups. A single ultrasonographic scan was offered to women in the screening arm of the study. Women with an AAA received follow-up scans, and were considered for elective surgery if certain criteria were met. RESULTS: The prevalence of AAA was six times lower in women (1.3 per cent) than in men (7.6 per cent). Over 5- and 10-year follow-up intervals, the incidence of rupture was the same in the screened and control groups of women. CONCLUSION: Screening women for AAA is neither clinically indicated nor economically viable.     

Cost-effectiveness of endovascular abdominal aortic aneurysm repair

BACKGROUND: The rapid introduction of endovascular abdominal aortic aneurysm repair (EVAR) has considerable implications for the management of abdominal aortic aneurysm (AAA). This study was undertaken to determine an optimal strategy for the use of EVAR based on the best currently available evidence. METHODS: Economic modelling and probabilistic sensitivity analysis considered reference cases representing a fit 70-year-old with a 5.5-cm diameter AAA (RC1) and an 80-year-old with a 6.5-cm AAA unfit for open surgery (RC2). Results were assessed as incremental cost-effectiveness ratio (ICER) compared with open repair (RC1) or conservative management (RC2). RESULTS: In RC1 EVAR produced a gain of 0.10 quality-adjusted life years (QALYs) for an estimated cost of 11,449 pound, giving an ICER of 110,000 pound per QALY. EVAR consistently had an ICER above 30,000 pound per QALY over a range of sensitivity analyses and alternative scenarios. In RC2 EVAR produced an estimated benefit of 1.64 QALYs for an incremental cost of 14,077 pound giving an incremental cost per QALY of 8579 pound. CONCLUSION:: It is unlikely that EVAR for fit patients suitable for open repair is within the commonly accepted range of cost-effectiveness for a new technology. For those unfit for conventional open repair it is likely to be a cost-effective alternative to non-operative management. Sensitivity analysis suggests that research efforts should concentrate on determining accurate rates for late complications and reintervention, particularly in patients with high operative risks.     

Ultrasonographic screening for abdominal aortic aneurysm.

OBJECTIVE--To assess the prevalence of abdominal aortic aneurysm in a selected group of men over the age of 60, and define main risk factors. DESIGN--Population based screening study. SETTING--Private Norwegian health maintenance organisation. SUBJECTS--500 men over the age of 60 years. INTERVENTIONS--General examination by a general practitioner, together with measurements of blood glucose and serum cholesterol concentrations. Abdominal scan with a B-mode ultrasound imager. MAIN OUTCOME MEASURES--An increase in the diameter of the aorta of more than 150% over the diameter at the origin of the superior mesenteric artery, or maximum diameter of more than 29 mm. Correlation with history of smoking, serum cholesterol concentration, and general health. RESULTS--29 patients (5.8%) had small, and 12 (2.4%) had large, abdominal aortic aneurysms. There was a significant association between aortic aneurysm and history of smoking (p < 0.01), poor health (defined as coexistent hypertension, cardiovascular disease, or diabetes mellitus) (p < 0.01), and increasing age (p = 0.025). There was no association with hypercholesterolaemia. CONCLUSION--Ultrasonic screening of groups at risk followed by elective operation may reduce mortality of abdominal aortic aneurysm.     

The case for expanding abdominal aortic aneurysm screening

Both the U.S. Preventive Services Task Force and the UK National Institute for Health and Care Excellence are re-evaluating their screening paradigms for abdominal aortic aneurysms (AAAs). Currently, most countries that screen for AAA do so only in male ever-smokers between the ages of 65 and 75 years and in patients with a family history of AAA. However, these recommendations are based primarily on screening trials predating the endovascular era. The wider applicability of endovascular aneurysm repair and its safety profile, especially in the elderly, have changed the risk-benefit of repair and, by extension, screening. This is despite the decreasing prevalence of AAA thanks to improved medical therapies and lower smoking rates. This evidence summary critically examines the evidence behind screening and the potential for expanded screening.     

Ultrasound screening for abdominal aortic aneurysm in medicare beneficiaries

Ultrasound screening for abdominal aortic aneurysm (AAA) has been shown to be beneficial and cost-effective for men aged 65-74. However, most screening studies have been conducted in Europe and Australia, where attendance for screening was higher than the single large U.S. study involving only veterans. The prevalence of AAA in the U.S. general population is not well defined, nor is the best method of recruitment for screening. Letters of invitation for a free screening ultrasound for AAA were sent to 30,000 randomly selected Medicare beneficiaries from the hospital referral region of three university-affiliated hospitals without restriction by age, gender, or comorbidity. Attendance for screening was calculated by age, gender, and travel distance to the screening center. Telephone calls to a random sample of nonresponders were made to determine the reason for failure to attend. Prevalence of AAA by ultrasound and known risk factors for AAA (e.g., age, gender, smoking status) were determined. The attendance rate was 7% (2,005). Attendance was greater with male gender (p < 0.01), younger age (p < 0.05), and decreased travel distance to the screening center (p < 0.05). The primary reasons for failure to attend included incorrect address or vital status, poor health, and lack of interest. Prevalence of previously undetected AAA was 2.8% in men and 0.2% in women. AAA was predicted by smoking status and male gender (p < 0.01 for each). Unselected invitation of Medicare beneficiaries for ultrasound screening for AAA results in a low attendance and low yield of AAA. The prevalence estimates from this study may not reflect the entire Medicare population given the low attendance and may reflect the healthy habits of those most interested in screening. Patients should be selected for screening based on their suitability for repair if an AAA is found as well as their risk factors for AAA. The best method of recruitment for screening of those most at risk for AAA in the United States remains to be determined.     

Endovascular abdominal aortic aneurysm repair in women

The objective of this review is to establish the role of endovascular aortic aneurysm repair (EVAR) in women. A step by step approach is taken looking at sex and gender differences in epidemiology, pathogenesis and natural history. We then proceed to discuss the results from the three randomized controlled trials comparing EVAR to open repair. Finally, sex-specific secondary prevention, risk factor management and medication, is discussed. Women seem to have higher mortality and more complications after EVAR. Risk factors such as diabetes and hypertension are associated with worse outcome in women compared to men. The role of EVAR in women is poorly investigated and its definite role remains to be determined. Aggressive treatment of risk factors and the optimisation of medication in women are indicated and deserve more attention in clinical practice and future research.     

Measuring abdominal aortic diameters in routine abdominal computed tomography scans and implications for abdominal aortic aneurysm screening

Objective

This study aimed to determine the prevalence and relevance of incidental abdominal aortic aneurysm (AAA) on routine abdominal computed tomography (CT) and to audit the performance of radiologists to identify and report AAA.

Psychological consequences of screening for abdominal aortic aneurysm and conservative treatment of small abdominal aortic aneurysms.

OBJECTIVE: To describe the potential psychological consequences of screening for abdominal aortic aneurysms (AAAs). METHODS: The participants were prospectively and randomly sampled from a randomised screening trial for AAA and asked to complete a validated generic and global anonymous quality of life (QL) questionnaire by self-assessment (ScreenQL). Material case-control study: ScreenQL was completed once by 168 (48%) of 350 non-responders to screening, 271 (81%) of 335 attenders before screening, 286 (85%) of 335 attenders after screening, 127 (85%) of 149 with a small AAA diagnosed at screening, and 231 (66%) of 350 who were randomised not to be offered screening for AAA (controls). Prospective study (paired data): 127 men having a small AAA diagnosed. Twenty-nine (81%) of 36 men operated after initial conservative treatment. RESULTS: Initially, the QL score was 5% lower among men with a small AAA compared to the controls (p<0.05), mainly because of poorer health perception. The QL score declined significantly further to 7% below control values during the period of conservative treatment. This impairment was mainly due to a 21% and 15% reduction in scores relating to health perception and psychosomatic distress, respectively. However, all scores improved to control levels in patients operated on. The QL of attending men for screening was significantly lower than that of the controls and the attenders after the screening. No differences were noticed concerning the non-attenders. CONCLUSION: The offer of screening causes transient psychological stress in subjects found not to have AAA. However, diagnosis of an AAA seems to impair QL permanently and progressively in conservatively treated cases. This impairment seems reversible by operation. Nevertheless, the impairment seems considerable, and must be considered in the management of AAA and in the final evaluation of screening for AAA.