Overweight and Obese Have Better One-Year Survival After Heart Attack Than Normal Weight People
CHICAGO -- In a finding that leaves Duke University Medical
Center researchers scratching their heads and planning further
studies, it appears that overweight and obese heart attack
patients have better intermediate-term survival rates than
normal weight patients.
Additionally, since the researchers used data from two
international trials that enrolled nearly 16,000 patients from
37 countries, the researchers also found that Asia had the
highest percentage of normal weight people (58 percent), while
the U.S. had the highest combined rate of obese and very obese
While it seems intuitive that the overweight and obese would
do better than those who are very obese, the researchers
paradoxically found that one year after a heart attack, the
death rate for normal weight patients was 4.3 percent, compared
to 2.7 percent for those overweight, 2.2 percent for the obese,
and 2.6 percent for the very obese.
"We know that obesity is a risk factor for coronary artery
disease, but no one has really studied its effect on
intermediate-term outcomes in this high-risk set of patients,"
said Eric Eisenstein of the Duke Clinical Research Institute.
He presented the results of the Duke study today April 1, 2003)
during the 52nd annual scientific sessions of the American
College of Cardiology.
"We tried adjusting the data for all the possible risk
factors, patient characteristics and treatment choices we could
come up with, but the effect persisted," Eisenstein continued.
"We have already begun further analysis to better understand
this phenomenon, as well as to gauge the economic impacts."
Eisenstein and colleague Duke cardiologist Kristin Newby,
M.D., consulted the data collected from two related
international trials -- SYMPHONY and 2nd SYMPHONY (Sibrifaban
vs. aspirin to yield maximum protection from ischemic heart
events post-acute coronary syndromes) -- that enrolled a total
of 15,904 patients at 931 sites around the world.
The researchers then grouped patients into one of four
groups -- normal, overweight, obese and very obese -- based on
what is called the Body Mass Index (BMI). The BMI is intended
to take into account the relationship of weight and height. It
is calculated by dividing weight in kilograms by height in
meters squared. A BMI range of 18.5 to 25 is considered
For their analysis, the Duke team eliminated 833 underweight
patients (BMI less than 18.5) and ranked the remaining study
participants according to their BMI group: normal (18.5 to 25);
overweight (25 to 29.9); obese (30 to 34.9); very obese
(greater than 35).
In addition to having the highest death rate after one year,
normal weight patients also had the highest death rate (2.6
percent) after 90 days, as compared to overweight patients (1.6
percent), obese patients (1.3 percent), very obese patients
After only 30 days, normal weight patients had a death rate
of 1.7 percent, compared to overweight patients (1.0 percent),
obese patients (0.9 percent) and very obese patients (1.2
Interestingly, said the researchers, those patients
considered overweight or obese tended to be younger and have a
more adverse cardiovascular risk profile. They also tended to
be treated more aggressively, which might partially explain
their better outcomes.
In addition to having the highest rates of obese and very
obese, the U.S. also has the smallest percentage of normal
Internationally, the percentage of normal, overweight,
obese, very obese follow:
Australia/New Zealand -- 26 -- 47 -- 20 -- 7
Asia -- 58 -- 36 -- 5 -- 1
Latin America -- 28 -- 46 -- 20 -- 6
Eastern Europe -- 29 -- 48 -- 18 -- 4
Western Europe -- 31 -- 48 -- 17 -- 4
United States -- 22 -- 41 -- 24 -- 13
Canada -- 23 -- 47 -- 23 -- 7
While the overweight and obese appear to have this
intermediate-term benefit, the researchers said their findings
do not constitute an argument against weight reduction.
"This is particularly important given the epidemiological
evidence that shows obesity is an independent predictor for the
development of cardiovascular disease and is associated with
the development of diabetes, high blood pressure and elevated
lipid levels," Newby said. "Whether therapies targeted
specifically at weight reduction will impact the development of
coronary artery disease or clinical outcomes after heart attack
remains to be proven in randomized clinical trials."
Both of the SYMPHONY trials were funded by F. Hoffmann-La
Roche, Basel, Switzerland. The Duke team's analysis was
supported by the Duke Clinical Research Institute.
Joining Eisenstein and Newby were, from Duke, Mahjushri
Bhapkar, David Kong, M.D., and Robert Califf, M.D. Darren
McGuire, University of Texas Southwestern Medical Center, also