Even Well-Controlled Diabetes May Present Post-Surgery
MONDAY, Oct. 18 (HealthDay News) -- People with diabetes who had
normal blood sugar levels before non-heart surgery had a higher
risk of death in the year following surgery compared to people
without diabetes, researchers have found.
And, patients who hadn't been diagnosed with diabetes but had
high blood sugar readings before surgery had a higher risk of death
in the year after a surgical procedure compared to people with
lower blood sugar readings, they noted.
"When we looked at blood sugar levels and the likelihood of complications after surgery, we didn't see a significant difference between diabetics and non-diabetics. But, when we looked at the long-term outcomes, we found significant differences between diabetics and non-diabetics," said Dr. Basem Abdelmalak, director of anesthesia for bronchoscopic surgery at the Cleveland Clinic in Ohio.
Findings from the study were scheduled to be presented Monday at
the Anesthesiology 2010 meeting in San Diego.
The researchers collected information from one preoperative
blood test to assess fasting blood sugar levels before 61,536
non-cardiac surgeries. Abdelmalak said the surgeries were varied,
and included all surgeries that weren't related to the heart.
From this large sample, about 16 percent of the surgical
patients had either type 1 or type 2 diabetes.
The average age of the patient population overall was 57,
according to Abdelmalak. The average age of the non-diabetic
patient was 56, and the diabetic group was slightly older, with an
average age of 63, he said.
The researchers compared the one preoperative blood sugar
reading to short- and long-term postoperative complications and
The investigators found that people with diabetes had between an
8 percent and 11 percent risk of dying in the year following
surgery. But those with lower blood sugar levels before surgery --
in the range of about 60 milligrams to 90 milligrams per deciliter
(mg/dL), according to Abdelmalak -- had a risk of death between 10
percent and 18 percent.
In people without diabetes, another interesting relationship
emerged. Those with a blood sugar level of more than 200 mg/dL had
more than an 11 percent risk of death in the year after surgery
compared to just 3 percent to 5 percent for non-diabetics with
lower blood sugar levels.
Abdelmalak said that one reason the non-diabetics with high
blood sugar levels had an increased risk of death might be because
they have undiagnosed diabetes. Diabetes, especially type 2
diabetes, can go unrecognized for long periods, but at the same
time is still causing damage to the body. So, these people may have
already been at a higher risk from complications related to
As for the finding that people with a low blood sugar level are
more likely to die in the year after surgery, Abdelmalak
hypothesized that the body may get used to living with higher blood
sugar levels -- in essence, resetting the body's metabolism. If you
then try to maintain "normal" blood sugar levels, these may then be
too low for you.
"We are still looking for the best way to give advice for managing diabetes during surgery. We're hoping that this study will stimulate further research, and that hopefully, we'll reach agreement on what is the better, or even optimal level of blood glucose," said Abdelmalak.
"We have abundant data that achieving good blood sugars without causing hypoglycemia has many benefits that are still worth striving for," explained Dr. Richard Bergenstal, president of medicine and science for the American Diabetes Association.
"Initially, it seemed that the lower the blood sugars could be recommended for everybody. But, now it looks as if we might need to individualize target blood sugars. However, we are still trying to sort out what are the right targets for which patients," said Bergenstal.
In the meantime, both experts suggested that people who haven't
been diagnosed with diabetes, but who have high blood sugar levels
before surgery, may need to be followed more closely after surgery
since they have a higher risk of death. And, the same holds true
for people with diabetes who have lower blood sugar levels.
To learn more about managing diabetes well, visit the
U.S. National Diabetes Education Program.
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