EVIDENCE-STATEMENT:

ABDOMINAL AORTIC ANEURYSM (Screening) Why This Chapter is Important for Employers: An Overview

• An abdominal aortic aneurysm (AAA) is a potentially fatal abnormal swelling (often balloon-like) of a segment of the body’s largest artery, the aorta. The wall of the artery bulges out rather than remaining straight.1 • Abdominal aortic aneurysms affect 4% to 8% of older men and 0.5% to 1.5% of older women.2-6 • Older age, smoking, male sex, and family history are the most significant AAA risk factors.2-6 • Approximately 69% of men in the United States age 65 to 74 years have a history of smoking (defined as lifetime consumption of more than 100 cigarettes) and are therefore at risk for AAA.7 • Although AAAs may be asymptomatic for years, as many as 1 in 3 eventually rupture if left untreated.8 • Voluntary AAA screening may reduce AAA-related mortality by 43% in men age 65 to 75 years.9 Therefore, it is particularly important that employers who provide retiree health care coverage or who have active employees over the age of 65 provide coverage for AAA screening. • In 2003, AAA (without rupture) was responsible for $2.7 billion in hospital charges and AAA rupture was responsible for an additional $639.71 million. Each patient treated for AAA (without rupture) costs more than $59,000; each hospital-treated patient with an AAA rupture costs more than $93,000.10 • The average cost of elective surgery following AAA screening is $25,000; the average cost of emergency AAA surgery following a rupture is approximately $50,000.11 Clinical Preventive Service Recommendations

U.S. Preventive Services Task Force Recommendation

The U.S. Preventive Services Task Force (USPSTF) recommends one-time screening for abdominal aortic aneurysm (AAA) by ultrasonography in men aged 65 to 75 who have ever smoked.12

Evidence Rating: B (Recommended/ At Least Fair Evidence)

The USPSTF found good evidence that screening for AAA and surgical repair of large AAAs (5.5 cm or more) in men aged 65 to 75 who have ever smoked (current and former smokers) leads to decreased AAA-specific mortality. There is good evidence that abdominal ultrasonography, performed in a setting with adequate quality assurance (i.e., in an accredited facility with credentialed technologists), is an accurate screening test for AAA. There is also good evidence of important harms of screening and early treatment, including an increased number of surgeries with associated clinically-significant morbidity and mortality, and short-term psychological harms. Based on the moderate magnitude of net benefit, the USPSTF concluded that the benefits of screening for AAA in men aged 65 to 75 who have ever smoked outweigh the harms.12

Information Sources

The recommendations and supporting information contained in this document came from several sources, including the: • Agency for Healthcare Research and Quality (AHRQ) 107

EVIDENCE-STATEMENT: Abdominal Aortic Aneurysm (Screening)

• • • •

American College of Cardiology Harvard Medical School Peer-reviewed research U.S. Preventive Services Task Force (USPSTF)

The background and supporting information contained in this document is a compilation of research findings. All information presented in this document should be attributed to its referenced source and should not be considered a reflection of other organizations cited in the text. Condition/Disease Specific Information Epidemiology of Condition/Disease

An abdominal aortic aneurysm (AAA) is a potentially fatal abnormal swelling (often balloon-like) of a segment of the body’s largest artery, the aorta. The wall of the artery bulges out rather than remaining straight.1 Abdominal aortic aneurysms are found in 4% to 8% of older men and 0.5% to 1.5% of older women.2-6 Aortic aneurysms account for approximately 15,000 deaths in the United States annually; of these, 9,000 are AAA-related and the remainder are due to thoracic aortic aneurysms.13-14 Once an aortic aneurysm develops, it is a lifelong condition. Most abdominal aortic aneurysms grow larger with time, expanding at an average rate of .33 centimeters to .5 centimeters each year. As many as 1 in 3 AAAs eventually rupture if left untreated.8 In about 20% of cases, an undiscovered abdominal aneurysm ruptures without warning and the patient collapses and dies from massive bleeding inside the abdomen. Most AAAs do not cause any symptoms, however when present, symptoms may include: • Pain in the abdomen, back, or the fleshy part of sides between the bottom ribs and the hips. • A feeling of fullness after eating a small meal. • Nausea and vomiting. • A pulsating mass in the abdomen.

Condition/Disease Risk Factors

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Older age, smoking, male sex, and family history are the most significant AAA risk factors.2 Other risk factors include high blood pressure, high blood cholesterol levels, and obesity.15 Approximately 69% of men in the United States age 65 to 74 years are current or former smokers and are therefore at risk for AAA.7 A former smoker, also called an “ever smoker” is defined as anyone with a lifetime consumption of more than 100 cigarettes.7

EVIDENCE-STATEMENT: Abdominal Aortic Aneurysm (Screening)

Value of Prevention Economic Burden of Condition/Disease

An estimate of the total societal economic burden of AAA is not available. However, hospital discharge data from Health Cost and Utilization Project (HCUP) show that, in 2003, 45,986 patients were discharged with AAA (without rupture) with a mean length of stay of 6.7 days and aggregate charges of $2.7 billion.10 Therefore, the average AAA patient staying in the hospital cost more than $59,000. Hospital discharge data also show that in 2003, 6,815 patients were discharged with a ruptured AAA with a mean length of stay of 10.7 days and total charges of $639.71 million. The average cost per discharge for a ruptured AAA exceeded $93,000. Men accounted for 75% of all discharges and 80% of aggregate charges.10 The economic burden of AAA would be much larger if lost productivity, premature mortality, and morbidity costs were accounted for.

Workplace Burden of Condition/Disease

Detailed data on the workplace burden of AAA is not available. The workplace burden of AAA is likely to increase due to the rapidly aging workforce.

Economic Benefit of Preventive Intervention

Early detection and appropriate management of AAA through screening can prevent costs resulting from rupture or leakage. The average cost of emergency surgery for AAA is approximately $50,000, while elective surgery (following AAA screening) is only $25,000.11

Estimated Cost of Preventive Intervention

In 2004, the private-sector cost of screening for AAA averaged $115; approximately 95% of all paid claims fell within the range of $35 to $336.16

Estimated Cost of Treatment

The average cost of surgery for AAA is between $25,000 and $50,000 (in year 2004 dollars).11

Cost-Effectiveness and/or Cost-Benefit Analysis of Preventive Intervention

The Oregon Evidence-Based Practice Center (EPC) conducted an evidence synthesis of AAA screening studies.17-20 Their principal findings point to a costeffectiveness ratio for population-based AAA screening (compared with no screening) that lies in the range of $14,000 to $20,000 per quality-adjusted life year (QALY).15 In comparison to other preventive interventions and to commonly accepted cost-effectiveness benchmarks, screening for AAA is costeffective. Preventive Intervention Information

Preventive Intervention: Purpose of Screening

Screening for AAA allows clinicians to identify affected patients and those who require preventive surgery and can thereby prevent rupture or leakage of the aneurysm.

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EVIDENCE-STATEMENT: Abdominal Aortic Aneurysm (Screening)

Early intervention reduces AAA-specific mortality9 and is more cost-effective than emergency surgery.11 Benefits and Risks of Intervention

Ultrasonography of the abdomen is accurate21-22 and reliable23 in detecting AAAs and it does not expose patients to radiation. One-time AAA ultrasound screening and the surgical repair of large AAAs (5.5 centimeters or more) in men aged 65 to 75 who have ever smoked reduces AAA-related mortality by as much as 43%.9 The USPSTF found good evidence of important harms associated with screening and early treatment, including an increased number of surgeries with clinicallysignificant morbidity and mortality, and short-term psychological harms. Based on the moderate magnitude of net benefit, the USPSTF concluded that the benefits of screening for AAA in men aged 65 to 75 who have ever smoked outweigh the harms.12

Initiation, Cessation, and Interval of Screening

The USPSTF recommends a one-time screening ultrasound to look for abdominal aortic aneurysm in men aged 65 to 75 who have smoked at any time in their lives. The exact timing of the screen is left to the discretion of the clinician.12

Intervention Process

Ultrasonography of the abdomen is used to screen for AAA. Ultrasonography should be performed in an accredited facility with credentialed technologists.

Treatment Information

Treatment depends on the size of the aneurysm. The larger the aneurysm, the more likely it is to burst (rupture). Death rates for ruptured aneurysms and emergency surgery are higher than rates for scheduled repair of unruptured aneurysms. Surgery is almost always recommended for an aneurysm that is leaking. Surgery is generally recommended for people with aneurysms larger than 5.5 centimeters in diameter unless another illness makes surgery unusually risky. Even with no symptoms, a person with an aneurysm larger than 6.5 centimeters would almost always have urgent surgery to repair the problem. People with smaller aneurysms may be monitored with ultrasound tests (every 12 months for anyone with an aneurysm smaller than 3.5 centimeters and every six months for those with aneurysms larger than 3.5 centimeters) to determine if the aneurysm is growing larger.1 Health benefits should include provisions for follow-up and treatment.

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Strength of Evidence for the Clinical Preventive Service

The level of evidence supporting the recommendations contained in this chapter is described below. Evidence-Based Research: U.S. Preventive Service Task Force (USPSTF) Strength of Evidence: B (Recommended/At Least Fair Evidence) • The USPSTF recommends one-time screening for abdominal aortic aneurysm (AAA) by ultrasonography in men aged 65 to 75 who have ever smoked.12

Authored by: Lanza A, Sotnikov S, Vandiver KP. Abdominal aortic aneurysm evidence-statement: screening. In: Campbell KP, Lanza A, Dixon R, Chattopadhyay S, Molinari N, Finch RA, editors. A Purchaser’s Guide to Clinical Preventive Services: Moving Science into Coverage. Washington, DC: National Business Group on Health; 2006.

References: 1. Harvard Medical School. Aetna. Abdominal aortic aneurysm. Updated 2005 Nov 25 [cited 2006 Aug 8]. Available from: http://www.intelihealth.com/IH/ihtIH/WSIHW000/9339/31040.html. 2. Lederle FA, Johnson GR, Wilson SE, Chute EP, Hye RJ, Makaroun MS, et al. The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators. Arch Intern Med 2000;160:1425–30. 3. Lederle FA, Johnson GR, Wilson SE. Abdominal aortic aneurysm in women. J Vasc Surg 2001;34:122–6. 4. Lindholt JS, Henneberg EW, Fasting H, Juul S. Hospital based screening of 65–73 year old men for abdominal aortic aneurysms in the county of Viborg, Denmark. J Med Screen 1996;3:43–6. 5. Norman PE, Jamrozik K, Lawrence-Brown MM, Dickinson JA. Western Australian randomized controlled trial of screening for abdominal aortic aneurysm [Abstract]. Br J Surg 2003;90:492. 6. Vardulaki KA, Walker NM, Couto E, Day NE, Thompson SG, Ashton HA, et al. Late results concerning feasibility and compliance from a randomized trial of ultrasonographic screening for abdominal aortic aneurysm. Br J Surg 2002;89:861–4. 7. Schoenborn CA, Adams PF, Barnes PM, Vickerie JL, Schiller JS. Health behaviors of adults: United States, 1999–2001. National Center for Health Statistics. Companion Table 4.1. Vital Health Statistics. 2004 [cited 2004 Nov 15];10(219). Available from: http://www.cdc.gov/nchs/data/series/sr_10/sr10_219companion.pdf 8. Darling RC, Messina CR, Brewster DC, Ottinger LW. Autopsy study of unoperated abdominal aortic aneurysms. The case for early resection. Circulation 1977;56:II161–4. 9. Fleming C, Whitlock EP, Beil TL, Lederle FA. Screening for Abdominal Aortic Aneurysm: A Best-Evidence Systematic Review for the U.S. Preventive Services Task Force (Conducted by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024, Task Order Number 2, Rockville, Agency for Healthcare Research and Quality. 2005 Feb. Available from: www.preventiveservices.ahrq.gov. 10. Agency for Healthcare Research and Quality. Nationwide inpatient sample data set. Hospital Cost and Utilization Project. Rockville, MD: Agency for Healthcare Research and Quality. 2006 [cited 2006 Aug 8] Available from: http://hcup.ahrq.gov/HCUPnet.asp. 111

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11. Silverstein MD, Pitts SR, Chaikof EL, Ballard DJ. Abdominal aortic aneurysm: Cost-effectiveness of screening, surveillance of intermediate sized AAA, and management of symptomatic AAA. Proc (Barl Univ Med Centr) 2005 Oct; 18(4):345-67. 12. U.S. Preventive Services Task Force. Screening for abdominal aortic aneurysm. Recommendation statement. AHRQ Publication No. 05-0569-A. Rockville, MD: Agency for Healthcare Research and Quality; Feb 2005. Available from: http://www.ahrq.gov/clinic/uspstf05/aaascr/aaars.htm. 13. Table 1. Deaths, percent of total deaths, and death rates for the 10 leading causes of death in selected age groups, by race and sex: United States, 2000. National Center for Health Statistics. National Vital Statistics Report. 2002 [cited 2004 November 15]. Available from: www.cdc.gov/nchs/fastats/pdf/nvsr50_16t1.pdf. 14. Gillum RF. Epidemiology of aortic aneurysm in the United States. J Clin Epidemiol 1995;48:1289–98. 15. Meenan RT, Fleming C, Whitlock EP, Beil TL, Smith P. Cost-effectiveness analyses of population-based screening for abdominal aortic aneurysm: Evidence synthesis. AHRQ Electronic Newsletter Issue No. 159. Rockville, MD: Agency for Healthcare Research and Quality; February 4, 2005. Available from: http://ahrq.gov/news/enews/enews159.htm. 16. Thompson Medstat. Marketscan. 2004. 17. Fleming C, Whitlock EP, Beil T, Lederle F. Primary care screening for abdominal aortic aneurysm. Evidence synthesis No. 35 (Prepared by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024.) Rockville, MD: Agency for Healthcare Research and Quality. February 2005. Available from: www.ahrq.gov/clinic/serfiles.htm. 18. Multicentre Aneurysm Screening Study Group. Multicentre aneurysm screening study (MASS): cost effectiveness analysis of screening for abdominal aortic aneurysms based on four year results from a randomised controlled trial. BMJ 2002;325:1135-8. 19. Soisalon-Soininen S, Rissanen P, Pentikäinen T, Mattila T, Salo JA. Cost-effectiveness of screening for familial abdominal aortic aneurysms. VASA 2001;30:262-70. 20. Lee TY, Korn P, Heller JA, et al. The cost-effectiveness of a “quick-screen” program for abdominal aortic aneurysms. Surgery 2002;132(2):399-407. 21. Nusbaum JW, Freimanis AK, Thomford NR Echography in the diagnosis of abdominal aortic aneurysm. Arch Surg 1971;102:385–8. 22. Wilmink AB, Forshaw M, Quick CR, Hubbard CS, Day NE. Accuracy of serial screening for abdominal aortic aneurysms by ultrasound. J Med Screen 2002;9:125–7. 23. Wilmink AB, Hubbard CS, Quick CR. Quality of the measurement of the infrarenal aortic diameter by ultrasound. J Med Screen 1997;4:49–53.

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