Testing for Heart Risk More Cheaply

Here's a quick quiz: what's the world's No. 1 killer? It's not AIDS, TB or
malaria. The world's deadliest disease is heart disease, which kills nearly
18 million people a year. Once considered predominantly an affliction of the
wealthy, the prevalence of heart disease has been growing in the developing
world - 80% of heart-disease deaths now occur in low- and middle-income
countries, which has got global health workers and epidemiologists
considering better ways to screen, track and treat the illness.
Now it looks like screening, at least, could get a whole lot cheaper and
faster. A team of researchers publishing in the medical journal Lancet finds
that simple, inexpensive tests for cardiovascular risk factors - performed
in less than 10 minutes, using a scale, a tape measure and a blood-pressure
check - are every bit as effective at determining heart-disease risk as more
expensive procedures involving laboratory-based tests. It's not exactly a
do-it-yourself kit, but it can help doctors screen patients more quickly,
leading to potentially more effective treatment - in both the developed and
developing world.
The researchers, led by Thomas Gaziano at Harvard Medical School and Brigham
& Women's Hospital in Boston, trawled through data on 6,186 adults
participating in the Health and Nutrition Examination Survey. Participants
were initially examined in the early 1970s and had no prior history of
cardiovascular disease; they were tracked for 21 years, during which time
1,529 of the participants suffered cardiovascular events (such as heart
attacks, stroke, angina or heart failure), including 578 deaths due to heart
disease.
Researchers looked at patient measurements typically used to assess heart
disease risk: age, systolic blood pressure, smoking status, total
cholesterol, diabetes status and any hypertension treatment. They found that
they could substitute body mass index (or BMI, a ratio of height to weight),
a noninvasive measure, for the lab-based blood test for cholesterol and
still accurately predict patients' five-year cardiovascular disease risk.
Gaziano and his colleagues show that if simple measurements, like BMI, are
thoughtfully considered, doctors with fewer resources in the developing
world can screen for heart-disease risk just as effectively as their
counterparts in high-income countries. There is some question about whether
results can be applied accurately to other populations - for a given BMI,
for example, Asians tend to have a higher body-fat ratio than Caucasians -
but, in many ways, people of the 1970s may be more similar than not to
populations elsewhere today. In the '70s, people smoked a lot more tobacco
than today, and few were getting treatment for high blood pressure or high
cholesterol. That's not so different from 21st-century Russians or Eastern
Europeans, Gaziano suggests.
A second article in this week's Lancet shows that heart-disease risk factors
are rapidly becoming more common worldwide, even in sub-Saharan Africa,
where infectious disease remains a big killer. In theory, African doctors
should be among those who benefit most from the new paper's findings. In
resource-poor settings, saving the $1 to $3 cost of a lab blood test would
certainly be meaningful - but that's assuming the tests were being performed
to start with. The real savings are difficult to calculate, in large part
because the populations most likely to benefit from dropping lab tests are
those that are least likely to have any labs or technicians available be
doing them at all.
The reality is that some developing countries spend as little as $30 a year
per person in health care costs; the rich world spends thousands. For
patients in low- and middle-income countries, meaningful costs also include
the cost of taking time off work to take the test, then traveling back to
the clinic for the results. For those reasons, the World Health
Organization's current guidelines for assessing cardiovascular disease risk
where lab resources are scarce have already dropped the cholesterol testing.
The new findings may in the end offer more cost-saving potential - and raise
more interesting questions - in developed nations, where medical costs have
spiraled upward in the last two decades. Neither doctors nor patients may
want to drop cholesterol testing altogether - more information is better,
especially when the consequence of missing a diagnosis is heart attack - but
there is still a practical lesson to be learned. "I think we might use this
as an initial test," Gaziano says. "We can at least narrow the group of
people for whom we need to screen cholesterol." Those with very few other
heart-disease risk factors, for example, probably don't need the extra blood
work, since their cholesterol profile wouldn't make a big difference to
overall risk anyway. Similarly, those patients with several risk factors for
heart disease probably need treatment no matter what their cholesterol
levels. By giving blood tests only to those on the fence, doctors can save
resources for the tests and treatments that are warranted. [TM]