Thin People May Be at Greater Risk for Post-Surgery
MONDAY, Nov. 21 (HealthDay News) -- Thin people appear to have a
higher risk of dying within 30 days of an operation than heavier
people, researchers have found.
The reason for the finding isn't clear, the study authors said.
They set out to see what effect obesity had on survival after
surgery, but instead found that the thinner a patient was, the
greater the risk of death. The measurement the investigators used
was body mass index (BMI), which takes into account both height and
"Patients with low body mass index are at significantly higher risk of 30-day mortality following general and vascular surgical procedures," said lead researcher George Stukenborg, an associate professor in the department of public health sciences at the University of Virginia.
Body mass index is a significant predictor of death risk,
independent of the differences in risk associated with the type of
surgical procedure and other patient characteristics, he noted.
"Low body mass index should be recognized as an important risk factor for 30-day mortality and should be taken into account in preoperative decision-making, discharge planning and patient education," Stukenborg said.
The study was published in the Nov. 21 online edition of the
Archives of Surgery.
For the study, Stukenborg's team looked at deaths in the month
after operations in almost 190,000 people who underwent surgery in
2005 or 2006. The data came from the American College of Surgeons
National Surgical Quality Improvement Program.
Of these patients, more than 3,200 died within 30 days after
their operation. Of those with a BMI of less than 23.1, which put
them in the normal-to-thin range, the percentage who died was 2.8
percent, compared with 1 percent among people whose BMI was 35.3 or
higher (considered obese).
And those with a BMI of less than 23.1 had a 40 percent higher
risk of dying than people with mid-range BMIs of 26.3 to 29.6
(overweight), the researchers found.
According to the U.S. Centers for Disease Control and
Prevention, a BMI below 18.5 is underweight, between 18.5 and 24.9
is normal, 25 to 29.9 is overweight, and 30 and above is obese.
Patients who underwent exploratory abdominal surgery were at the
greatest risk of death (nearly 14 percent), compared to other
operations. The lowest risk was for breast lumpectomy, to remove
small tumors (0.1 percent).
Other procedures where BMI appeared to be a factor included
colostomy, wound cleaning, musculoskeletal system procedures, upper
gastrointestinal procedures, colorectal surgery and hernia repair,
the study authors noted.
"Unfortunately, our research does not shed any light on why BMI is a risk factor for mortality," Stukenborg said. "This is an interesting question, though, and something we should think more about," he added.
Commenting on the study, Dr. Nestor de la Cruz-Munoz, chief of
bariatric surgery at the University of Miami Miller School of
Medicine, said that he was not surprised by the finding. "It's kind
of something we suspected but no one has ever looked at it in a big
series like this," he said.
It makes sense that underweight people have a greater risk of
dying, de la Cruz-Munoz noted.
"A lot of these patients are malnourished -- maybe cancer patients, patients undergoing treatment for other medical problems. A lot of time these patients don't have the defenses to do well with a major surgery," he said. "These patients are not your skinny young girl, but more like a frail 80-year-old woman."
For more information on BMI, visit the
U.S. National Library of Medicine.
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