Tight Blood Sugar Control May Raise Risks in the ICU
TUESDAY March 24, 2009 -- People hospitalized in intensive care units, or ICUs, often experience spikes in blood sugar, and current practice is to try to lower these levels.
But a new study found that this strategy might actually boost the person's relative risk of death by 10 percent.
"Intensively lowering blood glucose in critically ill patients is not beneficial and may be harmful," said Dr. Simon Finfer, a senior staff specialist in intensive care at Royal North Shore Hospital in Sydney, Australia, and lead author of the study. "Based on our findings, we do not recommend pursuing a normal blood glucose level in critically ill patients."
Expert groups remain cautious about the study's findings, however. In a joint statement issued March 24, the American Diabetic Association (ADA) and the American Association of Clinical Endocrinologists (AACE) warned against "letting this study swing the pendulum of glucose control too far in the other direction, where providers in hospitals are complacent about uncontrolled hyperglycemia."
The study is published March 24 in the online edition of the New England Journal of Medicine to coincide with a presentation at the International Symposium on Intensive Care and Emergency Medicine in Brussels.
Intensive glucose lowering has been recommended to control high blood sugar, which is common in people who are acutely ill and has been associated with organ failure and death.
For the study, Finfer's team randomly assigned more than 6,100 ICU patients to either intensive or conventional blood sugar control. The researchers used infusions of insulin to achieve specific blood sugar levels. The participants were then followed for 90 days.
"We found that intensively lowering blood glucose levels increased a patient's risk of dying by 10 percent," Finfer said. Overall, 24.9 percent of those whose blood sugar was controlled by conventional means died within 90 days compared with 27.5 percent of those who were given intensive infusions -- about a one-tenth rise. The percentage of people who experienced hypoglycemia, or low blood sugar, was also higher in the intensely treated group compared with the conventional care group.
The findings reveal that the current practice of intensively lowering blood glucose increases the risk of death among patients in the ICU, Finfer said.
"International guidelines should be revised to reflect this new evidence," he said. "Many professional organizations recommend very tight glucose control for ICU patients. They will now need to take this new evidence into consideration and adjust their recommendations accordingly."
Dr. Silvio E. Inzucchi, a professor of medicine at Yale University School of Medicine and author of an accompanying journal editorial, believes the findings might change clinical practice in the ICU.
The study "raises a big question mark about intensive blood sugar control in intensive care patients," Inzucchi said. "We used to think that keeping the sugar levels in the normal range was a good thing. This study says the opposite. The truth is probably somewhere in the middle.
Sugar control "should be good in the hospital," he said. "It just need not be super tight."
For their part, the ADA and AACE stress that doctors must still closely monitor and manage the blood sugar levels of very ill patients.
The findings "should not lead to an abandonment of the concept of good glucose management in the hospital setting," the groups said in their joint statement. They also pointed out that the study compared outcomes for patients receiving either very strict glucose control or, in the conventional treatment arm, less strict but still well-controlled blood sugar management.
ADA and AACE have also convened a special inpatient task force to examine the issue.
"Complete recommendations from the panel will be published in Endocrine Practice and Diabetes Care later in the spring," according to the ADA/AACE statement. "Until more information is available, it seems reasonable for clinicians to treat critical care patients with the less intensive -- yet good -- glucose control strategies used in the conventional arm [of the study]."
Inzucchi also said that the best approach may be a more moderated control.
"Get the sugars down, but keeping them in the slightly elevated range, is probably not a bad thing, at least during the short course of most hospitalizations," he said. "Medicine is always changing as new evidence emerges. We need to incorporate new findings into our practice patterns."
And in similar research, a team led by Dr. Donald Griesdale of the University of British Columbia, Vancouver, examined data from 26 studies, including Finfer's.
Slated for publication in the April 14 issue of the Canadian Medical Association Journal, Griesdale's study found that insulin therapy designed to lower blood sugar in ICUs caused a six-fold increase in dangerously low blood sugar levels among patients.
"We suggest that policy-makers reconsider recommendations promoting the use of intensive insulin therapy in all critically ill patients," the authors wrote. However, because the study involved data from a spectrum of populations and illness severity, the team said that they "cannot exclude the possibility that some patients may benefit from intensive insulin therapy and be at less risk of hypoglycemic events."
Posted: March 2009