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DURHAM, N.C. -- The use of implanted defibrillators that keep
the heart beating in proper electrical rhythm to prevent
cardiac arrest appears to be cost-effective for those patients
who receive a significant mortality reduction, according to
researchers from Duke
Clinical Research Institute (DCRI), Stanford University and
the VA Palo Alto Health Care System, Calif. They analyzed eight
clinical trials of the devices to arrive at their
conclusion.

The cost-effectiveness of these potentially life-saving
implantable cardioverter defibrillators (ICD) is an important
public health issue, the researchers said, since the Centers
for Medicare and Medicaid Services (CMS) estimates that as many
as 500,000 of its patients could be eligible to receive these
expensive devices.

The results of the team's analysis demonstrated that
although expensive, in appropriate patients ICDs provide value.
However, given the number of patients now eligible for ICD
implantation, their analysis highlighted the need for further
research into which patients are at higher risk for sudden
cardiac death and therefore would benefit the most from this
therapy, since the devices would be the most cost-effective for
these patients, the researchers added.

ICDs are about the size of deck of cards and are surgically
implanted under the skin of the chest, with wires attached to
the heart. If the device senses a life-threatening irregularity
of the heart rhythm, it delivers an appropriate electric
impulse to bring the heart back into proper rhythm. ICDs have
been proven effective in reducing sudden cardiac death in
patients who had been resuscitated from a cardiac arrest, and
the eight trials were designed to determine whether the devices
could prevent sudden death in a healthier population of heart
patients.

"Of the eight trials, two found no mortality benefits, so
the use of an ICD was less effective and more expensive than
for patients who did not receive an ICD," said Gillian D.
Sanders, Ph.D., DCRI medical decision analyst and first author
of a paper published Oct. 6, 2005, in the New England Journal
of Medicine. "We found that the other six trials added
significantly to life expectancy but at an increased cost, and
that compared to control therapy, the cost of this additional
gain in life expectancy was in the range of commonly accepted
cost-effectiveness values."

"It is estimated that it would cost more than several
billion dollars annually to implant ICDs in those patients for
which they have been proven effective and are considered
cost-effective," she continued. "If physicians extend the use
of ICDs in lower-risk patients where the cost-effectiveness is
even less favorable, the societal costs with increase even
more."

Sanders led the study with colleagues from the Palo Alto
(Calif.) VA Health Care System and Stanford University. The
study was funded by the Department of Veterans Affairs, the
Agency for Healthcare Research and Quality, and the Blue Cross
Blue Shield Association Technology Evaluation Center.

For their analysis, the team used a model that accounts for
a wide range of variables, including patient characteristics,
whether the ICD generator needed replacement, clinical
outcomes, medical costs, and quality of life parameters. In
these analyses, researchers not only included the potential
medication, hospitalization, procedure and other medical costs,
but also took into account quality-of-life benefits patients
receive for their added life expectancies.

Each "patient" in the model, whether they received an ICD or
not, progresses year-by-year, with the outcome and cost
estimated based on data drawn from the eight clinical trial
results and studies published in the scientific literature. For
their analysis, the researchers used 2005 Medicare costs of
$27,975 for ICD implantation, and $18,390 for device
replacement. A typical ICD generator lasts about five to six
years.

From this model, the researchers could determine
quality-adjusted life years (QALY) for each patient and their
associated costs. According to Sanders, the generally accepted
range for a therapy to be considered cost-effective is $50,000
to $100,000 per QALY, with interventions costing under
$50,000/QALY generally being deemed good value for the money,
and anything over $100,000/QALY is normally not seen as
economically favorable.

"Our analysis demonstrated that as long as the benefit of
the devices lasted for more than seven years, the use of an ICD
costs less than $100,000/QALY compared to the control group,"
Sanders said. "The cost-effectiveness could be improved by
either lowering the cost of the device or extending the ICD
generator's life time."

Specifically, in the six trials where a definite mortality
benefit was achieved, the use of an ICD added 1.01 to 2.99
QALYs at an additional $68,300 to $101,500 in cost over the
patient's lifetime

"For those who benefited from ICD therapy, it was a large
benefit that came at a cost comparable to other therapies we
provide patients," she said, citing as examples the use of
external defibrillators on commercial jets ($36,000/QALY) and
the use of stents vs. angioplasty in patients with an acute
heart attack ($24,000/QALY).

Because the patient characteristics of the eight trials were
so different from each other, the researchers determined that
they could not pool all the data for one combined cost
effectiveness ratio, but instead reported their results
specific to the individual trials.

"In January, CMS agreed to cover the costs associated with
ICD implantation for patients with left ventricular dysfunction
as long as the patient's clinical data is entered into a
national ICD registry," she said. "We hope that as this data is
collected and analyzed, we will be able to better distinguish
the high-risk patients from the low-risk patients. This should
help to make ICD use more cost-effective."

The two trials that found no benefit were CABG-PATCH and
DINAMIT, while the other six trials were MADIT-I, MUSTT,
MADIT-II, DEFINITE, COMPANION and SCD-HeFT. The trials involved
ICDs produced by all the major device companies.

Joining Sanders, who also co-directs Duke's Center for the
Prevention of Sudden Cardiac Death, in the analysis were Mark
A. Hlatky, M.D., Stanford University and Douglas K. Owens,
M.D., M.S. VA Palo Alto Health Care System and Stanford
University.