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Diabetes Studies Lead to Confusion

Monday April 21, 2008
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In light of recent conflicting results of two multicenter studies, diabetes experts are telling healthcare providers to not change their glycemic management approach for most patients with type 2 diabetes.

The American Diabetes Association (ADA), according to a Feb. 13 statement, continues to advise most people with diabetes to strive for a hemoglobin A1c of less than 7%, while stressing the need to individualize treatment goals. A Feb. 6 statement from the ADA said less stringent A1c goals may be appropriate for patients with comorbidities, longstanding diabetes and minimal or stable microvascular complications, limited life expectancy, or a history of severe hypoglycemia, as well as for children. Hemoglobin A1c is a measure of blood glucose control over two or three months.

In view of safety concerns recently raised by the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study, a less intensive glucose-lowering regimen may be appropriate for high-risk diabetic patients, says a subinvestigator for ACCORD at the University of North Carolina (UNC).

“I wouldn’t push someone to an A1c less than 7.5% if that person had a past cardiovascular event or was age 55 with multiple [cardiovascular] risk factors and would need multiple drugs,” says April Goley, RN, MSN, a nurse practitioner at the UNC Diabetes Care Center, one of the ACCORD study centers.

Recent findings

In February one arm of the ACCORD trial was stopped early when it found a higher mortality rate in patients receiving intensive blood glucose-lowering treatment compared with standard treatment. The North American study had enrolled more than 10,000 participants who had type 2 diabetes and multiple cardiovascular risk factors.

A week later, the ADVANCE (Action in Diabetes and Vascular disease; preterAx and diamicroN-MR Controlled Evaluation) study reported contradictory results. This international trial, which involved more than 11,000 high-risk patients with type 2 diabetes, found no evidence of increased risk of death among patients receiving intensive blood glucose-lowering treatment.

Both studies tested lowering the A1c to below the standard recommendation of less than 7% for diabetic patients. ACCORD aimed for an A1c goal of less than 6%, and the target in ADVANCE was less than 6.5%.

Another institution’s response to ACCORD is to continue to follow ADA guidelines.
“Across the board with our physicians and nurse educators, we still are shooting for the A1c to be less than 7%,” says Caren Bryant, RN, BSN, nurse educator, endocrinology department, Carle Clinic, Urbana, Ill. That advice includes patients with cardiovascular risk factors, she adds. Carle was not involved in either study.

Patients in the ACCORD trial were at especially high risk for heart attack and stroke. They also had A1c levels higher than most U.S. patients with type 2 diabetes have — about 8.2% at the beginning of the study, according to the study sponsor, the National Heart, Lung and Blood Institute. The study’s investigators reported that reasons were unclear for the slightly higher number of deaths among patients receiving stringent glycemic control, compared with the group receiving standard treatment targeting an A1c of 7% to 7.9%. But, according to preliminary analysis, the increased mortality was not due to hypoglycemia or any particular medication, including rosiglitazone (Avandia).

To lower their A1c below 6%, ACCORD participants in the intensive treatment group required a lot of medication as well as lifestyle changes, Goley says. Her center did not participate in ADVANCE, but she says the patient population had milder diabetes than those in the ACCORD study. Both studies were in older adults with type 2 diabetes.

“The findings of these two studies may not be generalizable to all diabetic populations,” Goley says.

Other treatment approaches

Past studies established that keeping blood glucose levels as close to normal as possible dramatically reduces diabetic complications. However, there is more that nurses can do to help their diabetic patients besides monitor blood sugar levels, Goley says.

“Until we can clarify the inconsistencies in studies of glycemia, there are other areas we can focus on,” she says. “Lowering the LDL [low-density-lipoprotein cholesterol], lowering blood pressure, and using aspirin have been shown to reduce cardiovascular disease outcomes.”

Carle Clinic’s Bryant cautions that clinicians should not use the A1c exclusively for monitoring blood glucose control.

“An A1c below 7% does not necessarily always denote good glycemic control,” she says. “Daily blood glucose checks also are important.”

What Diabetes Experts Say About A1c Goals

“A target of an A1c of 6.4% or less may not be ... possible, wise, or safe in type 2 patients with a higher risk of cardiovascular disease or those with established cardiovascular disease. Since the risk/benefit ratio from any therapy will differ from patient to patient, the clinician will need to make individual judgments about what is most appropriate.”

American Association of Clinical Endocrinologists (www.aace.com)

“AADE would like to caution the diabetes community against changing blood glucose monitoring treatment recommendations based solely on the findings of the ACCORD study. The data, as of now, is incomplete, and there are many factors that could have played a role in the increased morbidity rate of the patients in this trial.”

American Association of Diabetes Educators (www.diabeteseducator.org)

“It is premature to reach any definitive conclusion on this ACCORD study until the actual data are published. ...It seems clear that we may very well have different glycemic targets for different populations of patients, as opposed to our current strategy of attempting to achieve a specific A1c target for the majority of our patients.”

Irl Hirsch, MD, author of commentary, April 2008 Journal of Clinical Endocrinology & Metabolism (http://jcem.endojournals.org)

“We concur with the general recommendation of the ADA that advises people with diabetes to aim for an A1c level of less than 7%. However, for this special group of individuals with diabetes, as exemplified in the ACCORD population, which were average age of 62, had diabetes for an average of 10 years, and had known heart disease or were at high risk, less stringent A1c goals are likely appropriate, with an aim for around 7%, understanding that treatment should be individualized.”

Elizabeth Nabel, MD, director, National Heart, Lung and Blood Institute (www.nhlbi.nih.gov)

Kathy Louden is a freelance writer in Illinois. To comment, e-mail editorNTL@gannetthg.com.