Menu
Tip of the Day
Title: Hyperglycemia and ACS: Much More Work Needed
Lead author of the paper, Dr Prakash Deedwania (University of California, San Francisco), told heartwire: "Two million people each year in the US [United States] suffer from ACS, but we are focusing only on recanalization of the coronary artery. We are ignoring other prognostic indicators. There is plenty of evidence that hyperglycemia is a frequent problem in patients with ACS arriving at the hospital -- as many as 25% to 50% are affected -- but elevated blood sugar is frequently ignored despite being strongly associated with increased mortality."
Deedwania said, "Normally, we write this kind of position statement after something is definitive, but in this case we are hoping to prompt national bodies to do studies, and we are informing the medical community that many gaps exist within our knowledge and that there is limited guidance regarding the evaluation and management of hyperglycemia in the ACS setting. This is a significant problem that cannot be ignored, but we should not be rushing into things until the key questions are answered. There is a lot of work that needs to be done."
Properly designed trials required
Deedwania explained that despite "millions of dollars" having being spent on trials looking at the effects of hyperglycemia in ACS, "none of them have been done properly. They were well-intentioned studies, but we have not achieved what we were supposed to have."
The questions that require answers include, first, a careful assessment of the true prevalence of hyperglycemia "in a prospective fashion," he says. "Next, and more important in my opinion, before rushing to treat all the ACS patients with hyperglycemia, we need to find the most suitable method to initially measure and subsequently monitor blood glucose in the acute setting of ACS. And then we need to define the target value for blood glucose.
"As you will see in our executive summary, we emphasize that we don't know what the ideal treatment goal should be, although we have given general guidance to keep plasma glucose below 140 mg/dL."
The writing committee members also stress that it has not been established definitively that there is benefit to treating hyperglycemia. Currently, says Deedwania, many academic centers and institutions have specific teams treating hyperglycemia in the intensive care unit (ICU) setting during ACS, "and they spend huge amounts of money, when we do not know, in a randomized fashion, whether this will alter outcomes.
"The time has come to review this, and specific protocols need to be designed. This is a call to the [National Institutes of Health] NIH and other national bodies, as these are the only kind of institutions that can conduct the large trials required," he stressed to heartwire.
Is elevated glucose a marker or a mediator?
Central to all of these issues, Deedwania notes, is the key question that needs to be answered, which is "whether elevated blood glucose is a marker or a mediator of more severe myocardial damage."
If the former is the case, "we are barking up the wrong tree," he says.
Despite not being able to issue definitive recommendations on treating hyperglycemia in ACS, Deedwania says the scientific statement does offer some guidance to doctors.
"Hospitals should be on the lookout and make sure they evaluate ACS patients for hyperglycemia," says Deedwania. "If there is a problem, we would suggest trying to at least keep glucose under some control. Although we don't have a specific goal, we have suggested a reasonable target range of 80 to 140 mg/dL."
In patients hospitalized with ACS but not in the ICU, efforts should be made to keep plasma glucose levels below 180 mg/dL with subcutaneous insulin, the recommendations say.
Control glucose but take care to avoid hypoglycemia
In the ICU, most units that do control hyperglycemia do so using intravenous insulin, Deedwania says, "and while we recognize that this is currently the most effective way of controlling glucose in this setting, we don't know whether insulin is the right way to do it." Nevertheless, until research establishes a better way, they advise using insulin infusions with careful monitoring procedures and care taken to avoid hypoglycemia.
He acknowledges the potential for harm caused by hypoglycemia, as evidenced most recently by the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Although ACCORD has a different patient population -- type 2 diabetics at especially high risk of heart disease -- the fact that the blood-glucose-lowering arm of the trial was stopped prematurely earlier this month, due to a higher rate of mortality in the patients in the intensive arm vs those in the standard arm, cannot be ignored, says Deedwania.
He explains that this scientific statement on ACS and hyperglycemia was prepared before the decision was made to abandon the glucose-lowering arm of ACCORD: "But we were right on target. I'm not convinced that ACCORD says we should not be controlling glucose. What it does say is that there is a potential for harm [from hypoglycemia], at least in their study population."
Evaluate patients for diabetes before discharge
Finally, but possibly most important of all, is the need for ACS patients with hyperglycemia to be properly evaluated for diabetes, says Deedwania, who also serves on the AHA's Get-With-the-Guidelines diabetes committee.
"Even more central than whether acute treatment is going to have a significant impact or not is the message that these people should be investigated further for new-onset diabetes and for other things.
"We don't know, in these people who have this kind of hyperglycemic phenomenon in ACS, how often they are investigated. We recommend that they should all undergo fasting-glucose-tolerance testing and fasting-glucose testing before discharge from the hospital, and they should be carefully followed up afterward."
The study authors have disclosed no relevant financial relationships