Washington, June 9 : A new study has shown that nearly half of all heart surgery patients may experience blood sugar levels high enough to require temporary insulin treatment after their operation, even though they've never had diabetes.
The study, by researchers at the University of Michigan Health System, has shown that a significant minority of those patients might need to take medicines for days or even weeks after they leave the hospital, to help their blood sugar levels reach normal again.
Researchers found that obese patients, older patients, and those whose blood sugar levels were still high two days after their operation are most likely to need this kind of treatment.
The findings are based on a study, which included 1,362 patients who had certain heart and vascular operations at in 2006 and 2007.
Of them, 662 developed 'stress induced hyperglycemia' (SIH), or high blood sugar after surgery, and 87 needed blood sugar medicines when they left the hospital.
Stress-induced hyperglycemia occurs when the body reacts to the double insults of having an operation on the heart or major blood vessels, and of being cooled down by the heart-bypass machine to protect the heart muscle during surgery.
In the study, researchers looked at what happened after surgery, and what factors predicted a need for blood sugar treatment.
By far, the most telling sign that a person was likely to need such treatment - both in the hospital and as they went home - was their average blood sugar two days after surgery.
Those patients whose glucose levels were still high at this point were more than two and a half times more likely to need post-hospital medicines, even after other factors were considered.
Patients who had a body mass index (BMI) over 35, which is consistent with a diagnosis of obesity, were also somewhat more likely to develop SIH, as were older patients. owever, these factors were not nearly as strongly predictive of SIH as was the glucose level on the second day after surgery.
Still, researchers said, overweight patients who carry their excess weight mainly around their waists, in the form of belly fat, are more likely to have metabolic syndrome, which involves both increased cardiovascular risk and increased risk of diabetes.
Although the study didn't look at whether such patients later developed true diabetes or pre-diabetes, the results are striking enough to warrant a new study. t will recruit patients before their operations, and will include longer follow-up and more rigorous testing of pre-surgery and post-hospitalization blood sugar levels.
The study was presented at American Diabetes Association's Scientific Sessions in San Francisco.