An economic evaluation of an abdominal aortic
aneurysm screening program in Italy
Stefano Giardina, EconD,aBianca Pane, MD,bGiovanni Spinella, MD,bGiuseppe Cafueri, MD,b
Mara Corbo, EngD,aPascale Brasseur, EconD,dGiovanni Orengo, MD,cand Domenico Palombo, MD,b
Sesto San Giovanni (MI) and Genoa, Italy; and Tolochenaz, Switzerland
Objectives: Abdominal aortic aneurysm (AAA) is defined as a localized dilatation of an aortic vessel. Though predomi-
nantly asymptomatic, it is a chronic degenerative condition associated with life-threatening risk of rupture. The early
diagnosis of AAA, ie, before it ruptures, is therefore important; a simple, effective diagnostic method is ultrasound
examination. To assess the benefit of screening in Italy, we developed a cost-effective Markov model comparing screening
vs nonscreening scenarios.
Methods: A 13-health-states Markov model was developed to compare two cohorts of 65- to 75-year-old men: the first
group undergoing screening for AAA by means of ultrasound (US), the second following the current practice of
incidental detection. The following health states were distinguished: no AAA, unknown small AAA (3-3.9 cm),
followed-up small AAA (1 year), unknown medium-sized AAA (4-4.9 cm), followed-up medium-sized AAA (6 months),
unknown large AAA (>5 cm), elective repair, emergency repair, postelective-repair AAA, postemergency-repair AAA,
rejected large AAA, and death. Transitions between health states were simulated by using 6-month cycles. Transition
probabilities were derived from a literature review of relevant randomized controlled trial and from a screening program
that is currently ongoing at San Martino Hospital in Genoa, Italy. The Italian National Health Service (NHS) perspective
was adopted and incremental cost per life-year saved was calculated with a lifetime horizon; costs and health benefits were
discounted at an annual rate of 3% from year 2 onward. Uncertainty surrounding the model inputs was tested by means
of univariate, multivariate, and probabilistic sensitivity analyses.
Results: Considering an attendance rate of 62%, the individual cost per invited subject was €60 (US $83.2); 0.011
additional quality adjusted life years (QALY) were gained per patient in the screened cohort, corresponding to an
incremental cost-effectiveness ratio (ICER) of €5673/QALY (US $7870/QALY). The results were sensitive to some
parameter variations but consistent with the base case scenario. They suggest that on the basis of a willingness-to-pay
threshold of €50,000/QALY, screening for AAA is cost-effective, with a probability approaching 100%.
Conclusions: As in economic evaluations developed in other countries, such as the UK, Canada, and The Netherlands,
setting up a screening program for AAA can be considered cost-effective from the Italian NHS perspective. (J Vasc Surg
Abdominal aortic aneurysm (AAA) is defined as a per-
manent and irreversible condition caused by a failure of the
arterial wall that results in a dilatation with a diameter at
least 50% greater than normal,1according to age, gender,
body size and other factors. AAA is a potentially lethal
disease. It commonly remains without symptoms or causes
no specific symptoms until its most serious complication,
rupture, which is one of the most serious emergencies in
vascular surgery. AAA rupture causes about 6000 deaths
per year in Italy. In 50% of cases, death occurs before the
patient reaches hospital, and among those who reach the
hospital alive, the mortality rate after emergency treatment
is 30% to 70%2-4; therefore, the overall mortality rate is
between 65% and 85%.4
AAA rupture occurs mainly in men above 65 years old
with an abdominal aortic diameter larger than 5 cm.5,6The
age-specific prevalence of the condition is six times greater
occurs at a median age of 76 years in males and 81 years in
females, and with a median diameter of 8 cm.7By contrast,
the elective treatment of AAA that are detected early,
whether endovascular aneurysm repair (EVAR) or open
surgery (OS) is undertaken, is considered effective and safe,
with a mortality rate ?5%.8,9These observations empha-
size the importance of early diagnosis through ultrasound
(US), a technique which is noninvasive, economical, and
completely sensitive. Several experiences have shown that
early detection leads to a nearly 50% decrease in AAA
rupture and to a reported drop in mortality with a reason-
The aim of this study was to assess whether carrying out
a national program of systematic AAA screening in Italy
would be cost-effective according to the results of the
Screening Abdominal Aortic Aneurysm Genova (S.A.Ge)
From Medtronic Italia S.p.A., Sesto San Giovanni (MI)a; Vascular and
Endovascular Surgery,band Hospital Administration,cSan Martino
Hospital, University of Genoa, Genoa; and Medtronic International,
Competition of interest: Drs Giardina and Corbo are employees of
Medtronic Italia. Dr Brasseur is an employee of Medtronic International.
Medtronic has given a grant to San Martino University Hospital to fund
the screening project.
Reprint requests: Giardina Stefano, Medtronic Italia S.p.A., Piazza Indro
Montanelli 30, 20099 Sesto San Giovanni (MI), Italy (e-mail:
The editors and reviewers of this article have no relevant financial relationships
to disclose per the JVS policy that requires reviewers to decline review of any
manuscript for which they may have a competition of interest.
Copyright © 2011 by the Society for Vascular Surgery.
Endovascular Surgery Departments of San Martino Uni-
versity Hospital in Genova.
MATERIALS AND METHODS
Type of analysis. A cost-effectiveness analysis of two
was conducted to assess the costs and benefits of screening
years saved (LYS) were used as indicators of effectiveness.
The cost-effectiveness results are reported in terms of the
comparison of the incremental cost per QALY/LYS gained
with or without implementing a screening program for
AAA and are expressed by the cost-effectiveness ratio
The Italian National Health Service (NHS) perspective
was adopted to evaluate resource consumption with a life-
long time-horizon, by applying a 3% discount to both costs
and health benefits from year 2 onward. Uncertainty re-
garding the assumptions made and the variability of the
parameters used in the model was tested by means of
probabilistic and multivariate deterministic sensitivity anal-
Model outline. A 13-health-states Markov model was
developed to compare two cohorts of 65- to 75-year-old
men: the first undergoing screening for AAA by means of
US, the second following the current practice of incidental
The Markov model comprised the following health
states: no AAA, unknown small AAA (diameter 3-3.9 cm),
followed-up small AAA, unknown medium-sized AAA (di-
ameter 4-4.9 cm), followed-up medium-sized AAA, un-
known large AAA (diameter ?5 cm), elective repair, emer-
gency repair for ruptured AAA, emergency repair without
rupture, postelective-repair AAA, postemergency-repair
AAA, rejected large AAA, and death. Health states are
mutually exclusive and collectively exhaustive, meaning
that at any given time each subject is in one of the 13
possible health states and cannot be in more than one state
at the same time.
The model is based on some key assumptions:
(1) prevalence-based model;
(2) “One-shot” screening: if during screening no AAA is
found, patients will not undergo a second US test;
(3) US sensitivity is considered equal to 100%;
(5) AAA ?5 cm is assumed as the surgical threshold.
to calculate the outcome and the consumption of resources
for each group of patients.
The model analyzes the pathway for subjects who, after
refusing a written invitation to undergo AAA screening,
follow current practice (Fig 1), and the scenario in which
subjects agree to participate in the screening program (Fig
Fig 1. Current pathway. AAA, Abdominal aortic aneurysm.
JOURNAL OF VASCULAR SURGERY
Volume 54, Number 4
Giardina et al 939
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Submitted Sep 3, 2010; accepted Mar 12, 2011.
Jes S. Lindholt, MD, PhD, and Rikke Søgaard, MSc, MPH, PhD, Viborg, Denmark
Health economic modeling is a branch of decision-analytic
modeling often undertaken for the purpose of economic evalua-
tion of health care technologies. It has been defined by its appli-
cation of mathematical techniques to synthesize available informa-
tion about healthcare processes and their implications, thereby
decisions they inform.1
The role of health economic modeling for informing policy
decisions have evolved rapidly over the past decade. In particular,
since the National Institute for Health and Clinical Excellence
(NICE) in 2004 published their updated guideline on how to
appraise new and existing technologies, it could be read to favor
modeling over trial-based studies for the purpose of economic
The benefit of screening for abdominal aortic aneurysm
(AAA) has been demonstrated in large clinical trials and several
cost-effectiveness evaluations have followed from the UK, Finland,
USA, Canada, Sweden, The Netherlands, France, and Denmark.
While there is no reason to suspect that AAA behave differently
across the borders concerning growth and rupture, structural
differences in populations and health care systems typically restrict
the results to specific settings. For example, there will be variation
concerning attendance, prevalence of AAA, incidental detection
rates, proportion of ruptures reaching surgery, proportion fit for
repair, surgical outcomes, survival, and costs.
The present Italian model establishes a model structure that is
comparable to what we have seen in previous models. The popu-
lation of the model is largely based on relevant national and
international sources, although they have been selected qualita-
tively (and not upon systematic literature search and/or meta-
Concerns have been raised about the credibility of health
economic models due to a lack of transparency of earlier reports.3
In a forthcoming review on recent models of screening for AAA,
we observed some improvements on the previously identified poor
reporting standards.4However, a lack of model validation (com-
paring model outputs to observed outputs of eg, a randomized
clinical controlled trial or to national mortality statistics) remains a
threat to the credibility of health economic models, including the
present Italian model. Furthermore, it is our view that modeling
complex regimens of eg, screening for AAA usually cannot be
appropriately documented in a scientific manuscript of three to
4000 works. A separate technical paper is therefore warranted to
make the methodology fully transparent and to justify the under-
lying assumptions. A health economic model inherently is a sim-
plified representation of the real world.
1. Decision analytic modeling in the economic evaluation of health tech-
nologies. A consensus statement. Consensus Conference on Guidelines
on Economic Modeling in Health Technology Assessment. Pharmaco-
2. NICE. Guide to the methods of technology appraisal. London: Nice;
3. Campbell H, Briggs A, Buxton M, Kim L, Thompson S. The credibility
of health economic models for health policy decision-making: the case of
population screening for abdominal aortic aneurysm. J Health Serv Res
4. Søgaard R, Lindholt JS. Evidence for the credibility of health economic
models for health policy decision-making: a systematic literature review
regarding the case of screening for abdominal aortic aneurysms (resub-
mitted February 2011 after minor revision to Journal of Health Services
Research and Policy) J Health Serv Res Policy 2011; in press.
JOURNAL OF VASCULAR SURGERY
946 Lindholt and Søgaard