Mass screening on abdominal aortic aneurysm in men aged 60 to 65 years in The Netherlands. Impact on life expectancy and cost-effectiveness using a Markov model.

OBJECTIVES: To predict the costs and effects on life expectancy of an AAA screening programme. METHODS: A Markov model was designed to compare the effects of a single screening for a cohort of men 60-65 years with the current no screening strategy. The following health states were distinguished: no AAA, unknown small AAA, follow-up small AAA, unknown large AAA, repaired AAA, rejected large AAA and death. Transition rates between the health states were simulated using cycle times of one year. Transition probabilities were derived from literature and a previous feasibility study. Incremental costs per life year saved were calculated. Sensitivity analyses and discounting for future effects were performed. RESULTS: The expected individual AAA costs for non-screening and AAA screening were euro; 196 and euro; 530 respectively. A difference of 3.5 months life expectancy was found in favour of screening leading to euro; 1176/life-year gained. Costs increased as compliance fell. With a discount rate of 4% the costs are euro; 2021/life-year gained. CONCLUSIONS: One-time ultrasonographic screening for AAA in men aged 60-65 years appears to be cost-effective.     

Implications of screening for abdominal aortic aneurysms on surgical workload

BACKGROUND: The Multicentre Aneurysm Screening Study (MASS) provided strong evidence for both the clinical benefit and the cost-effectiveness of a screening programme for abdominal aortic aneurysms (AAAs) in men. If a national screening programme for AAA were adopted in the UK, it would be expected to increase the elective and decrease the emergency surgical workload. METHODS: The MASS trial randomized 67,800 men aged 65-74 years to be invited to attend for ultrasonographic screening for AAA or to a control group that received no invitation. Predictions of elective and emergency surgical workload were made for a 20-year interval after the introduction of a screening programme for 65-year-old men, based on surgical rates observed in the MASS trial and national mortality statistics. RESULTS: For a district general hospital serving a population of 400,000, there was an estimated reduction from nine emergency operations per year before introduction of the screening programme to three emergency operations annually in men aged 65 years and over by the end of the 20-year interval, and an increase from 24 to 43 AAA operations overall. The corresponding estimated annual costs for all AAA surgery increased by 47 per cent, from pound 209,000 to pound 308,000. These results were not affected by changes in the underlying assumptions. CONCLUSION: The results support the expectation of very few emergency operations, and principally elective operations, being performed following the introduction of a screening programme. For a typical district general hospital, a screening programme would be expected to lead to two additional elective AAA operations per month, and to save 11 AAA-related deaths per year.     

Late results concerning feasibility and compliance from a randomized trial of ultrasonographic screening for abdominal aortic aneurysm

BACKGROUND: The study was an update at 10 years of a randomized trial of the efficacy of screening for abdominal aortic aneurysm (AAA). The extent of benefit, feasibility and compliance were examined, and reasons why this intervention may fail a proportion of those screened were identified. METHODS: A total of 6058 men aged 65 years and over were randomized to a group invited to attend ultrasonographic screening or to a control group. The mortality rate from AAA in the two arms of the trial was compared using a Poisson model. Analyses were by intention to treat. RESULTS: There was a 21 per cent reduction in mortality rate from AAA over the 10-year follow-up (relative risk 0.79 (95 per cent confidence interval 0.53 to 1.40)). The observed relative mortality reduction peaked at 4 years with a 52 per cent reduction in the study group. Eighteen of 24 AAA deaths in the study group were among those who did not attend the first screen, or failed to comply with the follow-up protocol. CONCLUSION: A greater awareness of the benefits of full participation in a screening programme could provide a larger and sustained mortality reduction.     

Cost-effectiveness analysis of screening for abdominal aortic aneurysms based on five year results from a randomised hospital based mass screening trial.

BACKGROUND: The aim of this study was to estimate the cost effectiveness of screening for abdominal aortic aneurysm (AAA). MATERIAL AND METHODS: All 12,639 men born in the years 1921-1933 (aged 64-73) living in Viborg County, Denmark, were randomly allocated either to receive an invitation to abdominal ultrasound scanning for AAA or to be controls. Costs for screening and surveillance were assessed prospectively. Diagnosis Related Group (DRG) costs from 1999 were used concerning admissions with uncomplicated and complicated operations. Admissions for AAA surgery were retrospectively classified according to complications in patient records. RESULTS: Mean follow-up time was 52 months. 76.6% of invited men attended screening, and 191 (4.0%) had an AAA. As previously reported, the cumulative 5-year AAA-specific mortality in the invited group was significantly reduced by 67% compared to the control group (P = 0.003). The costs were estimated to be Euro 11.23 per scan. The costs per life-year saved were Euro 9057 (Euro 5872-20,063) after 5 years, and were expected to decrease to Euro 2708 (Euro 1758-6031) after 10 years and to Euro 1825 (Euro 1185-4063) after 15 years. CONCLUSION: Screening of 64-73 years old males in Denmark seems cost effective.     

Effectiveness and cost of screening for abdominal aortic aneurysm: results of a population screening program

OBJECTIVES: We undertook this study to calculate the cost per life-year gained in the first round of a screening program for abdominal aortic aneurysm (AAA) and to estimate the costs in a subsequent round. METHODS: This was an intervention study, with follow-up for ruptured aneurysms. Men older than 50 years were screened for asymptomatic AAA. Outcome measures included cost per life-year saved and number of men needed to be screened to save one life. RESULTS: The incidence of ruptured AAA was 2.6 per 10,000 person- years in the screening group and 7.1 per 10,000 person-years in the control group. Screening is estimated to have prevented 10.8 ruptured AAA and 8 deaths per year, gaining 51 life-years per year for the study population, and to have reduced the incidence of ruptured AAA by 64% (95% CI, 42%-77%). Each life-year gained during the first screening round cost $1107. To save one life, 1000 men need to be screened and 5 elective operations performed. We predict that a second round of screening can be cost neutral. CONCLUSIONS: The cost-effectiveness of screening for AAA compares favorably with screening programs for other disorders in adults.     

Screening for abdominal aortic aneurysms in men: a Canadian perspective using Monte Carlo–based estimates

Objective

Recently generated randomized screening trial data have provided good evidence in favour of routine screening for abdominal aortic aneurysm (AAA) to reduce AAA-related deaths in men aged 65 years and older. We developed an economic model that assessed the incremental cost–utility of AAA screening to help decision makers judge the relevance of a national screening program in Canada.

Methods

We constructed a 14 health state Markov model comparing 2 cohorts of 65-year-old men, where the first cohort was invited to attend screening for AAA using ultrasonography (US) and the second cohort followed the current practice of opportunistic detection. Lifetime outcomes included the life-years gained, AAA rupture avoided, AAA-related mortality, quality-adjusted life years (QALYs) and costs. Transition probabilities were derived from a systematic review of the literature, and a probabilistic sensitivity analysis was carried out to examine the effect of joint uncertainty in the variables of our analysis. The perspective adopted was that of the health care provider.

Results

Invitations to attend screening produced an undiscounted gain in life expectancy of 0.049 years and a gain in discounted QALY of 0.019 for an estimated incremental lifetime cost of CAN$118. The estimated incremental cost–utility ratio was CAN$6194 per QALY gained (95% confidence interval [CI] 1892–10 837). The numbers needed to invite to attend screening, and the numbers needed to screen to prevent 1 AAA-related death were 187 (95% CI 130–292) and 137 (95% CI 85–213), respectively. The acceptability curve showed a greater than 95% probability of the program''s being cost-effective, and the model was robust to changes in the values of key parameters within plausible ranges.

Conclusion

Our results support the economic viability of a national screening program for men reaching 65 years of age in Canada. More clinical studies are needed to define the role of screening in subgroups at high risk, especially in the female population.     

Cost-effectiveness of screening women for abdominal aortic aneurysm

BACKGROUND: Women are usually not considered for abdominal aortic aneurysm (AAA) screening because of their lower prevalence of disease. This position may, however, be questioned given the higher risk of rupture and the longer life expectancy among women. The purpose of this study was to assess the cost-effectiveness of screening 65-year-old women for AAA. METHODS: A systematic review of the literature was conducted to obtain data of importance to evaluate the effectiveness of screening women for AAA. Data were entered into a Markov simulation cohort model. RESULTS: The review suggested some main assumptions for women with AAA. Prevalence is 1.1%. In 6.8%, the AAA is of a size that merits surgery, and the patients are fit for a procedure. For patients with an AAA, the yearly risk for elective surgery and the rupture incidence was 3.1% and 2.4%, respectively, in the invited group and 1.1% and 5.7% in the noninvited group. The operative mortality for elective surgery was 3.5%, and the total mortality for ruptured AAA was 86.3%. The long-term mortality for AAA patients was 3.6 times higher than for an age-matched healthy population. Screening reduced the AAA rupture incidence by 33% and the AAA-related death rate by 35%. The cost per life year gained was estimated at $5911. CONCLUSION: The incremental cost-effectiveness ratio was similar to that found for screening men, which reflects the fact that the lower AAA prevalence in women is balanced by a higher rupture rate. Screening women for AAA may be cost-effective, and future evaluations on screening for AAA should include women.     

Fifteen-year follow-up of a randomized clinical trial of ultrasonographic screening for abdominal aortic aneurysms

BACKGROUND: Long-term benefits of screening for abdominal aortic aneurysm (AAA) are uncertain. These are the final results of a randomized controlled screening trial for AAA in men, updating those reported previously. Benefit and compliance over a median 15-year interval were examined. METHODS: One group of men were invited for ultrasonographic AAA screening, and another group, who received standard care, acted as controls. A total of 6040 men aged 65-80 years were randomized to one of the two groups. Outcome was monitored in terms of AAA-related events (surgery or death). RESULTS: In the group invited for screening, AAA-related mortality was reduced by 11 per cent (from 1.8 to 1.6 per cent, hazard ratio 0.89) over the follow-up interval. Screening detected an AAA in 170 patients; 17 of these died from an AAA-related cause, seven of which might have been preventable. The incidence of AAA rupture after an initially normal scan increased after 10 years of follow-up, but was still low overall (0.56 per 1000 person-years). CONCLUSION: Screening with a single ultrasonography scan still conferred a benefit at 15 years, although the results were not significant for this population size. Fewer than half of the AAA-related deaths in those screened positive could be prevented. Registration number: ISRCTN 00079388 (http://www.controlled-trials.com).     

Implications of Attendance Patterns in Northern Ireland for Abdominal Aortic Aneurysm Screening

Introduction

Evidence supports the introduction of an abdominal aortic aneurysm (AAA) screening programme. The aims of this study were to estimate future disease patterns and to determine the effect of the proportion attending on the programme’s cost-effectiveness.

Patients and methods

The results of the local AAA screening programme were reviewed. Ultrasonic infrarenal aortic diameter of 30 mm was considered aneurysmal. Projected population numbers from the Department of Health and current disease prevalence were used to estimate future number of potential patients. The Multi-centre Aneurysm Screening Study (MASS) Markov model was used to calculate an incremental cost-effectiveness ratio (ICER) and 95% uncertainty intervals (UI), using a 30-year time horizon and 3.5% per annum discount, to determine the effect of attendance.

Results

Men were recruited from August 2004 to May 2010. 13316 were invited for a scan and 5931 (44.5%) attended. 321 AAA were diagnosed, giving a prevalence of 5.4%, while 27 large AAA (0.46%) were repaired. The annual incidence of AAA until 2021 will range from 441 to 526, with an incidence of 40–48 large AAA, with both showing a gradual increase with time. Using this attendance rate, the ICER was calculated at £2350 per life-year gained (95% UI: £1620–£4290), or £3020 per quality-adjusted life-year gained (95% UI: £2080–£5500).

Conclusions

The prevalence of disease in this local AAA screening was similar to other studies. The low attendance will result in many AAA being missed, but will not impact greatly on the long-term cost-effectiveness.     

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.     

Elective Versus Ruptured Abdominal Aortic Aneurysm Repair: A 1-Year Cost-Effectiveness Analysis

Abdominal aortic aneurysm (AAA) is a life-threatening condition with an overall mortality of 80%. It predominantly affects men 65-74 years of age and is caused by focal distension of the main blood vessel in the abdomen. Most patients go undetected until their aneurysm ruptures. Controversy surrounds the most appropriate form of screening for AAA. Currently, screening is only carried out selectively in patients with peripheral vascular disease. Some patients have their AAA detected incidentally, whilst ultrasound examination of the abdomen is carried out for other indications. These patients have the opportunity to undergo surveillance or elective surgery. The mortality rate of emergency surgical intervention following rupture (50%) is far worse in comparison to that of patients undergoing planned intervention under specialist vascular surgeons (5%). Despite improvements in outcomes from elective intervention for AAA as a result of specialisation, the overall mortality from this condition remains very high (80%) as the commonest presentation of an AAA is rupture. Screening all men aged 65-74 years is considered too costly in the current economic climate. However the cost difference between elective repair and emergency repair of AAA must be considered given that the outcome from elective AAA repair is far superior to that following ruptured AAA repair. Our objective was to retrospectively collect costs and outcomes of elective and emergency AAA repair in order to carry out a cost-effectiveness analysis. Four multiprofessional teams in accident and emergency, operation theatres, intensive care, and surgical wards at the Kent and Canterbury Hospital were selected from health-care professionals including doctors, managers, nurses, and clerical staff with the purpose of obtaining costs. Detailed cost data collection sheets were prepared to calculate costs, which included staff costs, consumables including drugs, intravenous fluids, equipment, investigations, laundry, catering, and stationery. An inventory of costs per item was obtained, and the total cost was calculated from the number of items used. Outcomes were measured in terms of survival. The total costs of emergency AAA repair were ￡96,700.69, with a cost per life saved of ￡24,175.17. The total cost of elective AAA repair was ￡76,583.22, with a cost per life saved of ￡5,470.23. Emergency intervention for AAA was found to cost five times more than a planned intervention per life saved per year.     

Final follow‐up of the Multicentre Aneurysm Screening Study (MASS) randomized trial of abdominal aortic aneurysm screening

Background:

The long‐term effects of abdominal aortic aneurysm (AAA) screening were investigated in extended follow‐up from the UK Multicentre Aneurysm Screening Study (MASS) randomized trial.

Methods:

A population‐based sample of men aged 65–74 years were randomized individually to invitation to ultrasound screening (invited group) or to a control group not offered screening. Patients with an AAA (3·0 cm or larger) detected at screening underwent surveillance and were offered surgery after predefined criteria had been met. Cause‐specific mortality data were analysed using Cox regression.

Results:

Some 67 770 men were enrolled in the study. Over 13 years, there were 224 AAA‐related deaths in the invited group and 381 in the control group, a 42 (95 per cent confidence interval 31 to 51) per cent reduction. There was no evidence of effect on other causes of death, but there was an overall reduction in all‐cause mortality of 3 (1 to 5) per cent. The degree of benefit seen in earlier years of follow‐up was slightly diminished by the occurrence of AAA ruptures in those with an aorta originally screened normal. About half of these ruptures had a baseline aortic diameter in the range 2·5–2·9 cm. It was estimated that 216 men need to be invited to screening to save one death over the next 13 years.

Conclusion:

Screening resulted in a reduction in all‐cause mortality, and the benefit in AAA‐related mortality continued to accumulate throughout follow‐up. Registration number: ISRCTN37381646 ( http://www.controlled‐trials.com ). Copyright © 2012 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.     

The Long-term Benefits of a Single Scan for Abdominal Aortic Aneurysm (AAA) at Age 65

AIM: To investigate the efficacy of a single ultrasonic scan at age 65 to identify patients at risk from ruptured abdominal aortic aneurysm (AAA). METHOD: A total of 6058 men aged 64-81 were recruited to a randomised trial, and 3000 were invited to attend a single screening test. An additional population of 1011 men was offered screening as they reached age 65. If a normal aorta was identified in this sub-group, further scans were offered at two-yearly intervals. Follow up and treatment of those identified as having an aortic dilatation of 3 cm or greater was undertaken. All subject groups were monitored for deaths occurring over the study period, and date and cause of death were recorded. RESULTS: A total of 2212 men attended screening in the randomised trial; the overall compliance was 74%, and prevalence of AAA was 7.7%. Compliance decreased, and prevalence increased, with age. Mortality from ruptured AAA was reduced by 68% at 5 years (screened group compared to the age-matched control population), and by 42% in the study arm (screened and refusers) compared with controls. The benefit persisted at ten years (53% and 21% respectively). Of the uncontrolled sample of 1011 men offered a scan at age 65, 681 attended and 649 of these were found to have a normal aortic diameter; re-screening demonstrated new aneurysm development in 4% over ten years. The aortic diameters of the new AAAs were under 4 cm and would therefore have a low risk of rupture.1 Mortality from rupture in all those with an initially normal aortic diameter was low, at 1 case per 1000 scans over ten years. CONCLUSION: Screening once for AAA at age 65 can identify the majority of AAA that are of clinical significance and can identify a large population at low risk from rupture who do not require surveillance. This policy has been effective when combined with selective treatment in reducing the risk of rupture for ten years in those who attend the screening programme.     

Screening for abdominal aortic aneurysm in a geographically isolated area

BACKGROUND: Screening for abdominal aortic aneurysm has been shown to reduce aneurysm-related mortality, but the applicability of the results to the whole of the UK has been questioned. This study examined screening in a remote and rural area. METHODS: Over 3 years, men aged 65-74 years were offered screening in the community by ultrasonography, usually in general practitioner surgeries. Men with an aneurysm were rescanned at intervals or assessed for surgery. The screening and hospital costs of the programme were calculated. RESULTS: Some 9323 men were offered screening of whom 8355 (89.6 per cent) attended. Uptake was high in all areas. A total of 430 scans (5.1 per cent) were abnormal; 40 men had an aneurysm greater than 55 mm in diameter. Twenty further men had an aorta that enlarged to greater than 55 mm during follow-up. A total of 54 men had elective repair with one death (mortality rate 2 per cent). The cost of screening alone was 16 pound per invitation and the overall cost of the programme, including surgery, was 58 pound per invitation. CONCLUSION: Screening for abdominal aortic aneurysm can be carried out in a remote and rural area with high uptake, acceptable clinical results and at no greater cost than in more densely populated areas.     

Late survival after elective repair of aortic aneurysms detected by screening.

BACKGROUND: The aim of this study was to examine whether there was any survival advantage in men following elective repair of an abdominal aortic aneurysm (AAA) detected by ultrasound screening compared to those with an AAA detected incidentally. METHODS: A total of 424 men underwent elective AAA repair between 1990 and 1998; 181 were detected in an aneurysm screening programme and 243 were diagnosed incidentally. Follow-up survival data were collected until 2003 (minimum 5 years) and survival curves were compared using regression analysis. RESULTS: The postoperative 30-day mortality rate was significantly lower in men whose aneurysms were detected by screening (4.4%), compared with those detected incidentally (9.0%). Similarly, 5-year survival (78% vs. 65%) and 10-year survival rates (63% vs. 40%) were better after repair of a screen-detected AAA (p<0.0003 at all time intervals, by log rank testing). Multivariate analysis showed that this was largely due to the older age of men who had repair of an incidental AAA (71.2 vs. 67.1 years). CONCLUSION: Men who had elective repair of an AAA detected by screening had a better late survival rate than men whose aneurysm was discovered incidentally because they were younger at the time of surgery.     

Abdominal aortic aneurysm screening in Sweden

A large body of evidence from four international randomised controlled trials (RCT) on abdominal aortic aneurysm (AAA) screening indicate that ultrasound-based screening in elderly men with a high prevalence (4?%–7?%) reduces AAA-related mortality by 40?% through early AAA detection and increased preventive elective repair and subsequently halves rupture incidence. Coinciding with the planned launch of national AAA screening programs, a dramatic change in AAA epidemiology became evident: a lower AAA prevalence in the targeted population of men and falling mortality rates, most likely related to a drop in rates of smoking, and a paradoxical increase in elective AAA repairs. These changes have called AAA screening in today’s context into question. Sweden was the first country to provide national coverage with an AAA screening program targeting 65-year-old men. The scientifically evaluated screening initiative, started in 2006, reported the lower than expected prevalence (1.7?%) in 65-year-old men early on. Cost-effectiveness seems to be maintained despite the altered epidemiology, as shown in a health-economic study. The current prevalence of AAA among Swedish women is very low, and general population-based screening of women is likely to be futile, although targeted screening among female smokers should be evaluated. Sub-aneurysmal aortas detected at screening are likely to progress to a true AAA within 5 years, indicating a need for continued surveillance in this group. Differences in screening compliance seem to be linked to socio-economic factors. The aim of this topical review is to highlight AAA screening within a Swedish context and point to areas where information is lacking and further research is needed.     

Initial results of ultrasound screening for aneurysm of the abdominal aorta in Western Australia: relevance for endoluminal treatment of aneurysm disease

BACKGROUND: Increased life expectancy in men during the last thirty years is largely due to the decrease in mortality from cardiovascular disease in the age group 29--69 yr. This change has resulted in a change in the disease profile of the population with conditions such as aneurysm of the abdominal aorta (AAA) becoming more prevalent. The advent of endoluminal treatment for AAA has encouraged prophylactic intervention and fueled the argument to screen for the disease. The feasibility of inserting an endoluminal graft is dependent on the morphology and growth characteristics of the aneurysm. This study used data from a randomized controlled trial of ultrasound screening for AAA in men aged 65--83 yr in Western Australia for the purpose of determining the norms of the living anatomy in the pressurized infrarenal aorta. AIMS: To examine (1) the diameters of the infra-renal aorta in aneurysmal and non-aneurysmal cases, (2) the implications for treatment modalities, with particular reference to endoluminal grafting, which is most dependent on normal and aneurysmal morphology, and (3) any evidence to support the notion that northern Europeans are predisposed to aneurysmal disease. METHODS: Using ultrasound, a randomized control trial was established in Western Australia to assess the value of a screening program in males aged 65--83 yr. The infra-renal aorta was defined as aneurysmal if the maximum diameter was 30 mm or more. Aortic diameter was modelled both as a continuous (in mm) and as a binary outcome variable, for those men who had an infra-renal diameter of 30 mm or more. ANOVA and linear regression were used for modelling aortic diameter as a continuum, while chi-square analysis and logistic regression were used in comparing men with and without the diagnosis of AAA. FINDINGS: By December 1998, of 19,583 men had been invited to undergo ultrasound screening for AAA, 12,203 accepted the invitation (corrected response fraction 70.8%). The prevalence of AAA increased with age from 4.8% at 65 yr to 10.8% at 80 yr (chi(2)=77.9, df=3, P<0.001). The median (IQR) diameter for the non-aneurysmal group was 21.4 mm (3.3 mm) and there was an increase (chi(2)=76.0, df=1, P<0.001) in the diameter of the infra-renal aorta with age. Since 27 mm is the 95th centile for the non-aneurysmal infra-renal aorta, a diameter of 30 mm or more is justified as defining an aneurysm. The risk of AAA was higher in men of Australian (OR=1.0) and northern European origin (OR=1.0, 95%CL: 0.9, 1.2) compared with those of Mediterranean origin (OR=0.5, 95%CL: 0.4, 0.7). CONCLUSION: Although screening has not yet been shown to reduce mortality from AAA, these population-based data assist the understanding of aneurysmal disease and the further development and use of endoluminal grafts for this condition.     

The population prevalence of undetected abdominal aortic aneurysm in New Zealand Māori

BackgroundThe prevalence of abdominal aortic aneurysm (AAA) in Polynesian populations such as the New Zealand Māori has not been characterized. We measured this in a large population-based sample.MethodsA cross-sectional population-based prevalence study was conducted as part of an AAA screening pilot; 2467 Māori men aged 54 to 74 years and 1526 women aged 65 to 74 years registered with a primary care practice in Auckland (New Zealand) were invited to be screened by abdominal ultrasound between June 2016 and March 2018. Patients with pre-existing AAA disease and those with terminal conditions or circumstances that would make them unlikely to benefit from screening were excluded. The prevalence rate of AAA in Māori women was calculated with a cutoff definition of 27 mm as well as with the normal 30-mm definition (used in men). A log-binomial regression model estimated the prevalence rate at exactly 65 years for the purpose of comparison with screened populations in the United Kingdom.ResultsThe crude prevalence rate of undiagnosed AAA in Māori men aged 60 to 74 years was 3.6%. In women, it was 1.7% at the 30-mm threshold and 2.3% at 27 mm. The prevalence rate at exactly 65 years of age was calculated from the log-binomial regression model to be 2.7% (confidence interval [CI], 2.0%-3.8%) in men, 0.9% (CI, 0.4%-2.2%) in women at the 30-mm threshold, and 1.5% (CI, 0.7%-3.0%) in women at the 27-mm threshold. Among smokers, the crude prevalence rates were 7.5% (CI, 4.9%-11.5%) in men and 6.9% (CI, 4.1%-11.5%) in women (30 mm+).ConclusionsThe prevalence of undiagnosed AAA in New Zealand Māori men is considerably higher than in screened populations of equivalent age in the United Kingdom and Sweden. Prevalence rates in New Zealand Māori women are close to those of screened British men. New Zealand should consider implementing a population-based screening program for Māori men and conduct further research into the health impact of screening Māori women.     

Hospital costs and benefits of screening for abdominal aortic aneurysms. Results from a randomised population screening trial.

OBJECTIVES: to analyse the hospital costs and benefits of screening older males for abdominal aortic aneurysm (AAA). MATERIALS and METHODS: in 1994 a hospital-based screening trial of 12 658 65-73-year-old males was started. AAA >5 cm were referred for surgery. The remaining AAA were offered annual scans. Those with aortic ectasia were rescreened at 5 yearly intervals. AAA-operations and hospital AAA-related deaths were researched. The costs of screening, surveillance, and treatment were also registered. RESULTS: the attendance rate was 76%; of whom 191 (4.0%) had AAA. Mean observation time was 5.13 years. Sixty in the screened and 41 in the control group were operated (p=0.06), of which 7 and 27 respectively were operated as an emergency (p<0.001), and 6 and 19 respectively died due to AAA (p=0.009). The costs per scan were 83.50 DKK, 81 400 DKK per emergency operation (71 485 DKK after screening), and 117 000 DKK per emergency operation. The cost per prevented hospital death was 67 855 DKK, equivalent to approximately life year saved approx. 7540 DKK (GBP1=12 DKK). CONCLUSION: screening appears to reduce hospital AAA mortality and to be cost-effective.     

Ultraschallscreening auf abdominale Aortenaneurysmen (AAA)

Background

Abdominal aortic aneurysm (AAA) rupture is associated with a high mortality. The only preventive therapy is early diagnosis and elective surgery of rupture prone AAAs. Using B-mode sonography AAAs can be detected early with great reliability. Thus, a population-based ultrasound screening might lower the risk of abdominal aortic aneurysm ruptures.

Materials and methods

A literature analysis (until June 2014) was performed in the databases of MEDLINE, PubMed, and SCOPUS including all randomized controlled trials (RCT), systematic reviews, meta-analyses, health technology assessments (HTA reports) and medical guidelines on AAA screening. The following keywords were used: abdominal aortic aneurysm, ultrasound screening, evidence, guidelines. Clinically relevant endpoints were the following: AAA-associated mortality, overall mortality, number of elective AAA operations, number of ruptured AAAs and emergency surgery for different follow-up intervals.

Results

In four RCTs men between 65 and 83 years either had a single or no ultrasound examination of the abdominal aorta. Older women were only analyzed in one RCT. The meta-analysis of the RCT results shows that ultrasound screening caused a significant decrease of AAA-associated mortality, number of ruptured abdominal aneurysms, and number of emergency operations, whereas the number of elective surgeries significantly increased. Overall mortality was only moderately decreased by AAA screening.

Conclusion

Evidence was provided in population-based RCTs and meta-analyses for the efficiency of ultrasound based AAA screening for men older than 65 years. Presently the Federal Joint Committee (G-BA) and the Institute for Quality and Efficiency in Health Care (IQWIG) are evaluating a national ultrasound-based AAA screening program for Germany. However, additional clinical trials are necessary to assess risk groups especially men under 65 years, women with nicotine abuse and cardiovascular diseases which were underrepresented in previous studies.