Simple System Accurately Predicts Weight-Loss Surgery Risk
DURHAM, N.C. -- A simple scoring system based on five
medical factors accurately predicts which patients being
considered for gastric bypass surgery would be at highest risk
The scoring system, which was first proposed last year by
Duke University Medical Center surgeons, has been validated in
a new study of more than 4,400 patients. The system takes into
account a patient's weight, gender, age, blood pressure and
risk of developing a blood clot in the lungs.
Physicians using the system can easily determine if their
patients' risk of dying from the surgery is low, medium or
high. The new analysis found that patients in the high-risk
group were six times more likely to die than those in the
low-risk group, and patients in the medium-risk group were
three times more likely to die.
Gastric bypass surgery, also known bariatric surgery, is
used to help people who are morbidly obese lose weight.
Although the surgery has several variants, the basic procedure
involves stapling off a large portion of the stomach and
reattaching the intestine to the smaller remaining portion.
Because of their decreased stomach capacity, patients are
unable to eat as much food and feel sated much faster.
"This represents the first validated scoring system for
assessing risk for patients considering bariatric surgery,"
said Duke surgeon Eric DeMaria, M.D., who developed the system.
"The system gives surgeons concrete data they can use in
surgical decision-making and in their discussions with
patients. Also, the system provides standardization of surgical
outcomes, making comparisons among centers more
DeMaria presented results of the new study April 26, 2007,
at the annual meeting of the American Surgical Association, in
Colorado Springs, Colo.
Roughly 170,000 Americans underwent gastric bypass surgery
in 2005, according to the American Society for Bariatric
The new study examined data on 4,433 patients who underwent
bariatric surgery at the University of South Florida, the
Medical University of South Carolina and a private practice in
Of the 2,166 patients classified by the scoring system as
being in the low-risk group, eight died. Twenty-six of the
2,142 patients in the medium-risk group died, and three of the
125 patients in the high-risk group died. While patients in the
high-risk group represented less than 3 percent of the total,
they accounted for 8 percent of the deaths.
In the scoring system, patients with none or one of the five
medical factors are considered low-risk; those with two or
three factors are considered medium-risk; and those with four
or five factors are considered to be at the highest risk.
The factors are:
- A body mass index of greater than 50. On this scale, a
measure of body fat based on a person's weight and height, a
level of 30 and above is considered obese.
- Male gender. Men are more likely than women to suffer
from conditions such as hypertension, diabetes and metabolic
disorder that can add to the risks of surgery.
- Increased age. Patients over 45 are known to be at the
highest risk for death after bariatric surgery.
- Hypertension. Patients with hypertension, or high blood
pressure, typically have heart disease or chronic
inflammation of blood vessels that can add to the risks of
- Pulmonary embolus risk. Patients who have had a pulmonary
embolism, a blood clot in the lungs, or are at risk for
developing an embolism are at elevated risk.
"When talking to patients about bariatric surgery, we can
cite national averages on risks, but that is not very helpful
when I have a specific patient sitting in front of me," DeMaria
said. "Many physicians and patients see bariatric surgery as an
option to use only when all other approaches to weight loss
have failed. However, our system shows that this strategy may
need to be reconsidered.
"If patients put off surgery while they attempt other
weight-loss therapies that ultimately don't work, over time
they risk moving into a higher-risk category as they gain more
weight, get older or develop hypertension. In these cases,
delays can make surgery even riskier," DeMaria said.
For patients at highest risk, DeMaria said, the best
approach may be for them to spend some time losing weight
before the surgery. Alternatively, surgeons could perform a
series of smaller, and therefore less risky, procedures over