Could a simple
test save Medicare hundreds of millions?
Newswise — Next week, the Medicare
agency will announce whether it will cover the cost of a $400 heart
test that assesses a person’s risk of dying suddenly from a heart
condition.
Today, a study led by University of Michigan researchers
suggests that the test could actually save Medicare hundreds of
millions of dollars in the long run.
The researchers used a
sophisticated computer model to calculate the potential impact of
using the test, called microvolt T-wave alternans (MTWA), to help
determine which patients would benefit most from implanted devices
that automatically re-start a stopped heart.
Those devices, called implantable
cardioverter defibrillators, or ICDs, have been shown to save lives
that would otherwise have been lost to sudden cardiac death, which
kills 300,000 Americans each year.
One year ago, Medicare expanded
its coverage of ICDs to include many more heart patients; an
estimated 500,000 people over age 65 are now candidates. Covering
the cost of ICDs for patients who have the same characteristics as
participants in the MADIT-2 ICD trial that led to Medicare approval
could add $3 billion annually to the program’s budget. ICDs cost
$35,000 including implantation, require periodic battery
replacement, and pose a device failure risk.
In a presentation at the American
College of Cardiology Scientific Session, the U-M team suggests that
the MTWA test could spare a significant fraction of those costs, if
doctors focused on providing ICDs only to patients with an abnormal
or inconclusive MTWA test result. Previous studies have suggested
that patients with a negative, or normal, MTWA test result have a
far lower risk of sudden cardiac death than others.
This risk-stratification of ICD
candidates who meet MADIT-2 criteria, say the U-M researchers, could
potentially save Medicare $690 million a year — even after the cost
of the MTWA test and the care of patients who don’t receive ICDs are
included.
“ICDs have been shown in several
studies to be cost-effective, which means the cost is considered
acceptable given the benefit to patients,” says lead author and U-M
cardiology fellow Paul Chan, M.D., M.Sc. “But a very expensive
device can be cost-effective and still not affordable to society, if
the condition it treats is highly prevalent. Our study demonstrates
the potential impact of using additional factors to aid decisions
about the use of expensive devices.”
The MTWA test, he notes, is
gaining acceptance among cardiologists but will likely become more
common if Medicare decides to cover it.
Microvolt T-wave alternans are
small variations in the electrical impulses in the heart.
They can’t
be detected on the conventional heart-rhythm test called the
electrocardiogram (ECG), but MTWA test equipment can detect them via
special sensors placed on the patient’s body during a brief exercise
session.
Two companies make equipment that are used to perform MTWA
tests, but Chan and his colleagues have no association with those
companies, nor with companies that make ICDs.
At the ACC meeting, Chan will
receive the Parmley Prize for his previous research on the use of
the MTWA test as a way to predict sudden cardiac death in patients
with heart failure. In a study he presented last fall at the
American Heart Association Scientific Sessions that will soon be
published in the Journal of the American College of Cardiology,
he showed that ICD-eligible patients who met MADIT-2 trial criteria
for primary prevention of sudden cardiac death, and who had positive
or inconclusive MTWA results, were more than twice as likely to die
than similar patients with negative MTWA results. Other MTWA studies
have suggested a larger difference, but did not control for other
patient characteristics. Chan’s study also showed that about
one-third of patients who meet Medicare criteria for an ICD have
normal MTWA test results.
For the new study being presented
at the ACC meeting, which has been accepted for publication in JACC,
Chan and his colleagues used a computer model called a Markov
analysis to simulate the costs, benefits, and health outcomes of
65-year-old individuals who meet the MADIT-2 trial criteria for
Medicare coverage of an ICD. They looked at three scenarios: all
such patients get an ICD, only those with positive or inconclusive
MTWA results receive an ICD, or no patients get an ICD.
The model used a range of
assumptions about what percentage of patients would suffer sudden
cardiac problems and long-term complications with or without an ICD,
and how many ICD patients would suffer complications related to
their ICDs, It also included assumptions about what proportion of
patients would die depending on their treatment or MTWA status.
All
of these assumptions were based on data from previous ICD trials, or
best case/worst case scenarios. Costs for care were also included,
such as MTWA test costs, ICD costs, and the cost of medical care for
those who stayed healthy or suffered a heart problem with or without
an ICD.
To account for the uncertainties
inherent in each of the clinical variables, the researchers
performed various levels of sensitivity analyses, including an
analysis using 10,000 simulations in which all model variables were
randomly sampled.
This latter analysis, known as a Monte Carlo
simulation, allowed them to examine the distribution of possible
cost-effectiveness ratios for every quality-adjusted life year (QALY)
saved, and is a standard way to assess the cost-effectiveness of a
medical intervention.
It allows researchers to assess the cost of
saving a year of a person’s life, adjusted for the quality of that
life and the life-saving power of a particular course of action.
In general, the cost per QALY for
giving ICDs only to risk-stratified patients who had been tested
with MTWA was about $50,000, compared with medical therapy. “This is
well within the usual range considered cost-effective for new
medical technologies,” says Chan. However, compared with MTWA
testing followed by ICD use only in those with a positive or
inconclusive MTWA result, the all-ICD option would cost $88,700 per
QALY gained — under best-case scenarios.
Chan cautions that the new results
are not meant to guide doctors in decisions about whether or not to
suggest that particular primary prevention patients receive ICDs.
But he hopes the data may be useful in decisions about how to spend
resources for this type of care — and that further research will
examine how often doctors should conduct MTWA tests in patients who
don’t receive an ICD, to help them monitor for changes in sudden
cardiac death risk over time that might warrant an ICD.
In addition to Chan, the authors
of the ACC presentation are: Kenneth Stein, M.D., of Weill Cornell
Medical Center; Theodore Chow, M.D. of the Ohio Heart and Vascular
Center; A. Mark Fendrick, M.D., and Sandeep Vijan, M.D., M.Sc., of
the U-M Division of General Medicine; and J. Thomas Bigger, M.D., of
Columbia University.
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