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.     

The cost-effectiveness of early surgery versus watchful waiting in the management of small abdominal aortic aneurysms

Purpose: The purpose of this study was to compare the relative cost-effectiveness of two clinical strategies for managing 4 to 5 cm diameter abdominal aortic aneurysms (AAAs): early surgery (repair 4 cm AAA when diagnosed) versus watchful waiting (monitor AAA with ultrasound size measurements every 6 months and repair if the diameter reaches 5 cm).Methods: We used a Markov decision tree to compute the expected survival in quality-adjusted life years (QALYs) for each strategy, based on literature-derived estimates for the probabilities of different outcomes in this model. We determined hospital costs for patients undergoing elective and emergency AAA repair at our center. With standard methods of cost accounting, we then calculated the additional cost per year of life saved by early surgery compared with watchful waiting (cost-effectiveness ratio, dollars/QALY).Results: Mean hospital costs for elective and emergency AAA repair were $24,020 and $43,208, respectively (1992 dollars). For our base-case analysis (60-year-old men with 4 cm diameter AAAs, with 5% elective operative mortality rate and 3.3% annual rupture rate), early surgery improved survival by 0.34 QALYs compared with watchful waiting, at an incremental cost of $17,404/QALY. Increased elective surgical mortality rate, decreased AAA rupture risk, and increased patient age all reduced the cost-effectiveness of early surgery. Future increases in elective operative risk, noncompliance with ultrasound follow-up and increased threshold size for elective AAA repair during watchful waiting all improved the cost-effectiveness of early surgery. Future increases in elective operative risk, noncompliance with ultrasound follow-up and increased threshold size for elective AAA repair during watchful waiting all improved the cost-effectiveness of early surgery.Conclusions: The cost effectiveness of early surgery for 4 cm diameter AAAs in carefully selected patients compares favorably with that of other commonly accepted preventive interventions such as hypertension screening and treatment. With an upper limit of $40,000/QALY as an "acceptable" cost-effectiveness ratio, early surgery appears to be justified for patients 70 years old or younger, if the AAA rupture risk is 3%/year or more and the elective operative mortality rate is 5% or less. Although not a substitute for clinical judgment, this cost-effectiveness analysis delineates the essential tradeoffs and uncertainties in treating patients with small AAAs. (J VASC SURG 1994;19:980–91.)     

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.     

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.     

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.     

Abdominal aortic aneurysm rupture rates: A 7-year follow-up of the entire abdominal aortic aneurysm population detected by screening

Purpose: The goal of the current study was to identify the risk of rupture in the entire abdominal aortic aneurysm (AAA) population detected through screening and to review strategies for surgical intervention in light of this information. Methods: Two hundred eighteen AAAs were detected through ultrasound screening of a family practice population of 5394 men and women aged 65 to 80 years. Subjects with an AAA of less than 6.0 cm in diameter were followed prospectively with the use of ultrasound, according to our protocol, for 7 years. Patients were offered surgery if symptomatic, if the aneurysm expanded more than 1.0 cm per year, or if aortic diameter reached 6.0 cm. Results: The maximum potential rupture rate (actual rupture rate plus elective surgery rate) for small AAAs (3.0 to 4.4 cm) was 2.1% per year, which is less than most reported operative mortality rates. The equivalent rate for aneurysms of 4.5 to 5.9 cm was 10.2% per year. The actual rupture rate for aneurysms up to 5.9 cm using our criteria for surgery was 0.8% per year Conclusion: In centers with an operative mortality rate of greater than 2%, (1) surgical intervention is not indicated for asymptomatic AAAs of less than 4.5 cm in diameter, and (2) elective surgery should be considered only for patients with aneurysms between 4.5 and 6 cm in diameter that are expanding by more than 1 cm per year or for patients in whom symptoms develop. In centers with elective mortality rates of greater than 10% for abdominal aortic aneurysm (AAA) repair, the benefit to the patient of any surgical intervention for an asymptomatic AAA of less than 6.0 cm in diameter is questionable. (J Vasc Surg 1998;28:124-8.)     

Ruptured abdominal aortic aneurysm in a well-defined geographic area

OBJECTIVE: Despite an increasing number of elective operations on abdominal aortic aneurysms (AAAs), the age- and sex-standardized mortality rate of ruptured AAA (RAAA) continues to increase. In the Pirkanmaa region, population 440,000, all aortic surgery is performed at Tampere University Hospital (TAUH). Procedures have been collected into the vascular registry. The purpose of this study was (1) to establish the incidence, modes of treatment, and mortality of RAAA in a defined geographic area; (2) to evaluate the prerupture history to determine if there are any ways to prevent rupture; and to make a forecast about the increase of RAAAs in the next decades. METHODS: Population and outcome data in the Pirkanmaa region and information on all patients who died of RAAA during 1990-1997 were provided by Statistics Finland. All operated RAAAs that underwent procedures during 1990 to 1999 were identified from the local vascular registry. To make a forecast for the next decades, an incidence of RAAA was calculated separately for each age group in 5-year intervals. RESULTS: From 1990 to 1997, 221 patients presented with RAAA. The mean incidence was 6.3/100,000 inhabitants. The incidence in the population over 65 years was 35.5/100,000. The total RAAA mortality was 76.9%. A total of 139 patients reached TAUH and 111 underwent emergency surgery. The overall hospital mortality in TAUH was 63.3%. The calculated annual number of RAAA will increase 49.6% in the next 2 decades, and the overall incidence will increase from 6.3 to 8.9/100,000 inhabitants. According to the vascular registry, 166 patients were operated on for RAAA during 1990 to 1999 in TAUH. The 30-day mortality was 50.6%. A minority of the patients (n = 18, 10.8%) had a previously documented AAA. The median diameter at the time of rupture was 7 cm. Seven (5.0%) men and six (24.0%) women had a diameter of less than 5.5 cm. CONCLUSION: The incidence of RAAA in the Pirkanmaa region in 1990s was the Finnish average. In the next two decades, the number of individuals with RAAA will increase significantly. One quarter of women had a diameter of AAA at the time of rupture that was under the current threshold indicator for elective operation.     

Influence of presentation on outcome in abdominal aortic aneurysm repair.

OBJECTIVES: In the absence of formal screening abdominal aortic aneurysms (AAA) are detected in an opportunistic manner. Many remain asymptomatic and undetected until they rupture. Incidentally discovered small AAAs are entered into a surveillance programme until they reach a suitable size for repair. The aim of this study was to examine trends in the management of AAA and whether the method of presentation had an effect on subsequent mortality. DESIGN: Observational study in UK district general hospital. MATERIALS/METHODS: This study reports a single surgeon case series identified using a prospectively maintained database. Data on mode of presentation, management and mortality were retrieved from case notes, PIMS hospital database and the Office of National Statistics. RESULTS: Two hundred and five patients were referred with AAAs between 1992 and 2004, 78% presenting in elective circumstances. The surveillance programme fed 33% of the operated cases. Two aneurysms ruptured whilst under surveillance. Overall elective operative mortality was 11.8% and has progressively decreased over time. Thirty-day operated mortality was significantly lower in patients having a period of surveillance than those having immediate elective repair (2.3 vs. 16.3%, p=0.018). A slight reduction in emergency AAA repairs was noted over the study period (r2=0.6) although registered aneurysm deaths continue to increase (r2=0.83). CONCLUSIONS: Elective mortality following AAA surgery decreased over the study period. Outcome was better in those patients who had surgery for aneurysms that had been under surveillance. Despite opportunistic screening the population adjusted mortality rate of aortic aneurysms showed a progressive increase. A reduction in deaths from aneurysms is unlikely without a formal screening programme.     

A decade of change in abdominal aortic aneurysm repair in the United States: Have we improved outcomes equally between men and women?

OBJECTIVES: Abdominal aortic aneurysm (AAA) repair has undergone vast changes in the last decade. We reviewed a national database to evaluate the effect on utilization of services and rupture rates. METHODS: From the Centers for Medicare Services (CMS), a 5% inpatient sample was obtained for 1994 to 2003 as beneficiary encrypted files (5% BEF) and as a limited data set file after 2001. Files were translated into Microsoft Access by using a custom program. Queries were performed using International Classification of Diseases (9th Revision) (ICD-9) diagnosis codes 441.3 (ruptured AAA) or 441.4 (non-ruptured AAA) and ICD-9 procedure codes 38.34, 38.36, 38.44, 38.64, 39.25, 39.52 for open, and 39.71 (available after October 2000) for endovascular repair. The 5% BEF totals were multiplied by 20 to calculate yearly volumes. Total cases were divided into the yearly CMS population of elderly Medicare recipients for repair rates per capita and are reported as cases per 100,000 elderly Medicare recipients. Statistics were performed using chi2, Student's t test, nonparametric tests, and multiple regression analysis; P < or = .05 was considered significant. RESULTS: Elective AAA repairs declined from 94.4/100,000 in 1994 to 87.7/100,000 in 2003. AAA rupture surgery declined from 18.7/100,000 (1994) to 13.6/100,000 (2003). Rupture repairs from 1994 to 2003 decreased by 29% for men and by 12% for women (P < .001). Rupture mortality has not changed, but the average is significantly higher for women at 52.8%, with men averaging 44.2% (P < .001). Mortality for elective AAA repair has decreased from 5.57% (1994) to 3.20% (2003) in men (P < .001) and from 7.48% (1994) to 5.45% (2003) in women (P < .001). Multivariate analysis demonstrated increasing age, female sex, and open surgery (vs endovascular) were significant predictors of elective and ruptured AAA repair mortality. For 2003 elective AAA repairs, the average length of stay was 6.9 days in men and 8.9 days in women (P < .01) For 2003, men were more likely to be discharged to home after rupture (32.9% of men vs 23.3% of women; P < .001) and elective repair (84.5% of men vs 70.1% of women; P < .001). CONCLUSIONS: Improvements in AAA management in the last decade have decreased aneurysm-related deaths and reduced the incidence of aneurysm ruptures, with a lower utilization of services. Women, however, continue to have a consistently higher mortality for open and ruptured AAA repair and are less likely to return to home after either.     

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.     

Abdominal aortic aneurysmectomy in octogenarian patients

The authors report 56 patients. 80 years of age or older who had an abdominal aortic aneurysm (AAA): twenty seven were operated upon as emergencies, 7 with intra-peritoneal (Group I) and 20 with retro-peritoneal rupture (Group II). Twenty nine underwent elective surgery (Group III). Renal pulmonary and cardiac disease are frequent in octogenarian patients. The surgical repair consisted of 40 knitted bifurcated grafts and 16 aorto-aortic woven grafts. The overall in-hospital mortality rate is high (28.5%: 16 patients) essentially in "emergency" surgery: 71% for the seven Group I patients and 45% for the twenty Group II patients. The in-hospital mortality rate of 6.9% for the Group III of "elective" procedure is higher than the mortality rate of patients of all ages operated on for asymptomatic AAA in our institution which is 4.3%. Once a patient has been operated on successfully his life expectancy tends to parallel that of a normal population for his age group. These results can be improved with preventive measures such as elective surgery for asymptomatic AAA with a diameter of 6 cm or more. Operative contraindications are severe congestive heart failure, advanced pulmonary disease or neoplastic disease. The age "per se" is not a contraindication to aneurysmectomy. Physiologic rather than chronologic age should determine the selection for AAA in the over-80 age group. CT scans and MR are safe fast and non-invasive preoperative examinations for AAA.     

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.     

The place of screening in the management of abdominal aortic aneurysm

The present method of management of Abdominal Aortic Aneurysms (AAA) is ineffective in preventing AAA rupture. 5000 people still die of AAA in the UK each year. Improvements in surgery can only reduce the mortality in the minority who reach hospital following chance detection, and then only by a few percent. Screening, with detection in the community and planned treatment can reduce the mortality of the disease by 58%. Screening programmes for AAA have recently been approved for men aged 65 years, in both the UK and the USA. The proposed UK National Screening Programme is outlined briefly. CONCLUSION: If the aim of treatment is to reduce the mortality of the disease as a whole, resources would be better spent on screening programmes for AAA, rather than developing increasingly sophisticated operative techniques that could only reduce the overall death from AAA by a few percent.     

Emergency surgery of non-ruptured abdominal aortic aneurysm

BACKGROUND AND AIMS: The pain of an abdominal aortic aneurysm (AAA) is believed to signify rupture, and emergency surgery for symptomatic AAA is a widely accepted practice to prevent rupture. To clarify the benefit of emergency surgery we evaluated the clinical course of emergency treated patients with non-ruptured AAAs. MATERIAL AND METHODS: 110 patients (90 men, mean age 69, range 49-93; 20 women, mean age 75, range 63-89) underwent emergency repair of non-ruptured AAA between 1970 and 1992 at the Department of Thoracic and Cardiovascular Surgery of Helsinki University Central Hospital (HUCH). Survival rates after surgery were analysed using product-limit-survivorship method. The survival rates after age-stratification were compared with those of patients undergone elective surgery (n=599) or emergency surgery because of ruptured AAAs (n=363) during the same period. Risk factors affecting early and late survival rates after operation were analysed by logistic regression analysis and Cox proportional hazard model. RESULTS: Thirty-day operative mortality rates were 18 % (20/110) in the emergency non-ruptured group, compared with 7 % (42/599) in the elective group and 49 % (179/363) in the ruptured group (p<0.05). Thirty day survival rate was not changed among the nonruptured emergency group from 1970 to 1992, whereas the rates of ruptured and elective groups became better during the study period. Late survival rates for 30-day postoperative survivors were clearly reduced among the non-ruptured emergency group, without difference between the emergency operated ruptured and non-ruptured groups. Coronary artery disease was decreasing significantly early and late survival rates after emergency surgery for non-ruptured AAAs (p<0.05, logistic regression and p<0.001 Cox proportional hazard). CONCLUSIONS: Early and late mortality risk is significantly higher (p<0.001) after emergency surgery for haemodynamically stable non-ruptured AAA than after elective surgery, mainly because of coronary artery disease.     

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.     

Quality of life following surgery for abdominal aortic aneurysm.

Repair of abdominal aortic aneurysm (AAA) carries a considerable rate of morbidity and mortality, but little information exists on the quality of life following this procedure. During 1988 and 1989, in two hospitals, 211 patients (186 men and 25 women; median age 74 (range 48-87) years) underwent surgery for AAA. There were 77 ruptured aneurysms and 134 electively repaired. Of these, 38 patients died in hospital (27 ruptured, 11 elective); by the time of review a further eight (one ruptured, seven elective) had died from unrelated causes. Of the 165 survivors, 131 (45 ruptured, 86 elective) were reviewed and questioned as to their physical and mental state before and after surgery. Using the Rosser index, a value for quality of life before and after surgery was calculated (1.0, good; 0, dead). The value for the elective group was 0.94 before operation and 0.96 after, but in the ruptured group fell from 0.98 before surgery to 0.87 afterwards. This study shows that patients undergoing elective surgery for repair of AAA retain good quality of life. By contrast, patients surviving emergency surgery following this procedure seem to suffer a deterioration in life quality, which must be endured for the same expected lifetime as that for the elective group. These results support the need for a national AAA ultrasonographic screening programme.     

Cost-effectiveness of screening for hepatopulmonary syndrome in liver transplant candidates.

The hepatopulmonary syndrome (HPS) is present in 15-20% of patients with cirrhosis undergoing orthotopic liver transplantation (OLT) evaluation. Both preoperative and post-OLT mortality is increased in HPS patients particularly when hypoxemia is severe. Screening for HPS could enhance detection of OLT candidates with sufficient hypoxemia to merit higher priority for transplant and thereby decrease mortality. However, the cost-effectiveness of such an approach has not been assessed. Our objective was to perform a cost-effectiveness analysis from a third-party payer's perspective of screening for HPS in liver OLT candidates. The costs and outcomes of 3 different strategies were compared: (1) no screening, (2) screening patients with a validated dyspnea questionnaire, and (3) screening all patients with pulse oximetry. Arterial blood gas analyses and contrast echocardiography were performed in patients with dyspnea or a pulse oximetry (SpO(2)) < or =97% to define the presence of HPS. A Markov model was constructed simulating the natural history of cirrhosis in a cohort of patients 50 years old over a time horizon of their remaining life expectancy. Transition probabilities were obtained from published data available through Medline and U.S. vital statistics. Costs represented Medicare reimbursement data at our institution. Costs and health effects were discounted at a 3% annual rate. No screening was associated with a total cost of 291,898 dollars and a life expectancy of 11.131 years. Screening with pulse oximetry was associated with a cost of 299,719 dollars and a life expectancy of 12.27 years. Screening patients with the dyspnea-fatigue index was associated with a cost and life expectancy of 300,278 dollars and 12.28 years, respectively. The incremental cost-effectiveness ratio of screening with pulse oximetry (compared to no screening) was 6,867 dollars per life year gained, whereas that of the dyspnea-fatigue index (compared to pulse oximetry) was 55,900 dollars per life year gained. The cost-effectiveness of screening depended on the prevalence and severity of HPS, and the choice of screening strategy was dependent on the sensitivity of the screening modality. In conclusion, screening for HPS, especially with pulse oximetry, is a cost-effective strategy that improves survival in transplant candidates predominantly by targeting the transplant to the subgroup of patients most likely to benefit. The utility of screening depends on the prevalence and severity of HPS in the target population.     

Cost-effectiveness of surgery for small abdominal aortic aneurysms on the basis of data from the United Kingdom small aneurysm trial

PURPOSE: Although the United Kingdom small aneurysm trial reported no survival benefit for early operation in patients with small (4. 0-5.5 cm) abdominal aortic aneurysms (AAAs), the trial lacked statistical power to detect small but potentially meaningful gains in life expectancy, particularly for specific subgroups. We used decision analysis to better characterize the potential benefits and cost-effectiveness of early surgery. METHODS: We used a Markov model to assess the marginal cost-effectiveness (incremental cost per quality-adjusted life year [QALY] saved) of early surgery relative to surveillance for small AAAs, using data from the UK Trial. Subgroup analyses were performed by patient age and AAA diameter. Sensitivity analysis was used to evaluate the effect of elective operative mortality on cost-effectiveness. RESULTS: In our baseline analysis, early operations provided a small survival advantage (0.14 QALYs) at a small incremental cost of $1510. Thus, despite a small survival benefit, early surgery appeared cost-effective ($10, 800/QALY). The small cost differential resulted from the large proportion of patients who underwent surveillance, who eventually underwent AAA repair, and therefore incurred the cost of the surgical procedures. The survival advantage and cost-effectiveness of early operation increased with lower operative mortality, younger age, and larger AAA diameter. CONCLUSION: Despite the negative conclusions of the UK trial, early surgery may be cost-effective for patients with small AAAs, particularly younger patients (<72 years of age) with larger AAAs (> or = 4.5 cm). Because the gains in life expectancy are relatively small, however, clinical decision making should be strongly guided by patient preferences.     

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.