WORLD’S LARGEST TRIAL OF INTENSIVE GLUCOSE CONTROL IN TYPE 2 DIABETES FINDS SIGNIFICANT REDUCTION IN SERIOUS COMPLICATIONS – 21% REDUCED KIDNEY DISEASE RISK
June 6, 2008
The world's largest diabetes trial has shown intensive blood glucose control in type 2 diabetes reduces the risk of complications -- notably a 21% reduction in risk for kidney disease. The study also showed no evidence of any increased risk of death when blood glucose was intensively controlled, according to reports presented here today at the American Diabetes Association's 68th Scientific Sessions.
"The results clearly demonstrate that intensive control of blood glucose, as recommended by most current clinical guidelines, has an important role in the prevention of renal complications of type 2 diabetes. The other major finding of the trial was that major macrovascular events -- heart attack, stroke and death from cardiovascular disease -- were not significantly reduced with intensive glucose control, although there was a trend towards improvement in these outcomes. However, the results suggest that a multifactorial approach addressing all the major risk factors including blood pressure and blood lipids is required to prevent macrovascular disease," said Anushka Patel, MBBS, SM, PhD, Study Director of the ADVANCE trial, and Director, Cardiovascular Division, The George Institute for International Health, which conducted the study, in a recent interview. "The key message is that the study confirms the current approach that intensively controlling blood glucose has an important role in the prevention of the microvascular complications of diabetes."
There was no evidence of an increased risk of death among ADVANCE patients receiving intensive treatment to lower blood glucose, in contrast to the similar ACCORD trial in the U.S., which was discontinued prematurely earlier this year due to an increased rate of death in its intensive arm.
"Overall, we found that the intensive control strategy reduced the combined risk of macrovascular and microvascular complications by 10%, but that was driven largely by the microvascular results," said Dr Patel. "Further, the 14% reduction in microvascular risk was driven mainly by nephropathy rather than retinopathy. We found that intensively controlling blood glucose reduces risk of the development or progression of kidney disease by 21%."
ADVANCE did not show a statistically significant effect of intensive glucose control on cardiovascular disease (10% in the intensively treated group vs., 10.6% in the standard group). "We believe a protective effect remains plausible since we were aiming for a 1% difference in A1C levels between the standard and intensive groups, but achieved an average of a 0.7% difference over the course of the trial," said Dr. Patel. "Further, the rate of cardiovascular events was only 2.2% per year rather than the expected 3% per year, possibly due to more aggressive treatment of blood pressure and lipids." She also noted that the wide confidence interval in the trial's results does not exclude the benefits that epidemiologic evidence predicts.
A1C is a measure of blood glucose over the prior two to three months.
The ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron-MR Controlled Evaluation) trial was an international study involving 11,140 high-risk patients with type 2 diabetes based at 214 centers in 20 countries worldwide.
"ADVANCE was designed to address two of the major uncertainties in the prevention of the vascular complications of diabetes: whether important clinical benefits would result from reducing A1C to 6.5% or lower and from intensive blood pressure lowering, whether or not the patient had had hypertension," said Stephen MacMahon, DSc, PhD, MPH, Co-Principal Investigator of the study, Principal Director of The George Institute for International Health. He is also a Professor of Cardiovascular Medicine and Epidemiology at the University of Sydney. In a factorial design, patients received blood-pressure-lowering treatment with a fixed-dose combination of the angiotensin-converting enzyme inhibitor perindopril and the diuretic indapamide or a placebo, and diabetes treatment with gliclazide MR, plus other anti-diabetic drugs as needed.
The average age of participants was 66, with 46% coming from Europe, 37% from Asia, 13% from Australia and New Zealand, and 4% from North America. At the outset, 32% of the participants had already had a cardiovascular event, such as a stroke or heart attack, and the balance were already at high risk due to such risk factors as a history microalbuminuria (protein in the urine), proliferative diabetic retinopathy, current cigarette smoking, elevated total cholesterol, or low HDL (the "good" cholesterol).
"The key objective was to get the intensive group patients down to an A1C of 6.5%, which the trial achieved," said Dr. MacMahon. The investigators did not have a particular target for the standard group so they did not have control of what the standard group would achieve.
"At baseline, the average A1C of all participants was 7.5%," said Dr. MacMahon. "Physicians treating those in the standard group could give them any medications they chose according to the guidelines in the local country. Physicians treating those in the intensive group were required to use gliclazide MR first and then up to three oral agents, followed by insulin in order to reach the goal of an A1C of 6.5% or lower. Sulfonylureas, thiazolidinediones, acarbose, metformin, and insulin were commonly used in both arms of the study. Aside from gliclazide MR, all medication choices were left to the treating physician."
"At the end of the five years of follow-up, the average A1C in the intensive group was 6.5% and in the standard group was 7.3%," he reported. "However, the average difference in A1C over the course of the trial was 0.7%."
There were two primary outcomes: first, a composite of death and macrovascular complications -- death, cardiovascular death, nonfatal heart attacks, and nonfatal stroke; second, a composite of microvascular complications -- new or worsening renal disease (nephropathy) or diabetic eye disease (retinopathy). It was prespecified that the outcomes would be analyzed both jointly and separately.
"As expected, patients in the intensive group had more hypoglycemia (episodes of low blood glucose), but the overall incidence was actually quite low," he said. The incidence of severe hypoglycemic events was 2.7% in the intensive group and 1.5% in the standard group, and this difference was statistically significant.
Translating the Results to Action
"It's more challenging today than it has ever been in the past to demonstrate a benefit for glucose control first because the standard group was in such good control. Patients getting standard treatment are already in good glycemic control today and are also getting good treatments for cholesterol and blood pressure and are getting aspirin," said Dr. MacMahon. "So the overall rate of heart attacks is low, which means we might need a much larger group and a much longer study to detect the effects of glucose lowering on macrovascular outcomes."
"If there is any effect of glucose control using currently available drugs on heart attacks, it's going to be small, and therefore the key message with heart attacks and strokes is that diabetes patients need comprehensive treatment to control all risk factors including blood pressure and cholesterol," said Dr. MacMahon.
Nearly 21 million Americans have diabetes, a group of serious diseases characterized by high blood glucose levels that result from defects in the body's ability to produce and/or use insulin. Diabetes can lead to severely debilitating or fatal complications, such as heart disease, blindness, kidney disease, and amputations. It is the fifth leading cause of death by disease in the United States. Type 2 diabetes involves insulin resistance -- the body's inability to properly use its own insulin. Type 2 used to occur mainly in adults who were overweight and ages 40 and older. Now, as more children and adolescents in the United States become overweight and inactive, type 2 diabetes is occurring more often in young people. Globally, there are approximately 250 million people with diabetes, and that number is estimated to rise to 380 million in 2025.
Results of the blood pressure component of the trial, already published in the Lancet in September 2007 showed that a fixed combination of perindopril and indapamide given to patients with type 2 diabetes, regardless of baseline blood pressure, reduced the risks of vascular events by 9% over the course of five years. The relative risk of cardiovascular death was reduced by 18%.
ADVANCE was designed, conducted, monitored, analyzed and reported by an international collaborative medical research group. The study was led by The George Institute for International Health, funded by the Australian Government's National Health and Medical Research Council and by Servier, and carried out independently of the government and industry sponsors.
The George Institute for International Health seeks to improve the health of millions of people worldwide by providing the best research evidence to guide global health decisions and applying this research to health policy and practice. The George Institute is a leader in clinical trials, health policy and capacity-building areas and works in collaboration with medical institutions around the world.
Symposium, Friday, 2:00 pm PDT
NOTE TO EDITOR:
Visit http://www.diabetes.org/adablog to read blog posts from the Association's Scientific Sessions from former USA Today reporter, Anita Manning.
The George Institute for International Health
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About the American Diabetes Association
Nearly half of American adults have diabetes or prediabetes; more than 30 million adults and children have diabetes; and every 21 seconds, another individual is diagnosed with diabetes in the U.S. Founded in 1940, the American Diabetes Association (ADA) is the nation’s leading voluntary health organization whose mission is to prevent and cure diabetes, and to improve the lives of all people affected by diabetes. The ADA drives discovery by funding research to treat, manage and prevent all types of diabetes, as well as to search for cures; raises voice to the urgency of the diabetes epidemic; and works to safeguard policies and programs that protect people with diabetes. In addition, the ADA supports people living with diabetes, those at risk of developing diabetes, and the health care professionals who serve them through information and programs that can improve health outcomes and quality of life. For more information, please call the ADA at 1-800-DIABETES (1-800-342-2383) or visit diabetes.org. Information from both of these sources is available in English and Spanish. Find us on Facebook (American Diabetes Association), Twitter (@AmDiabetesAssn) and Instagram (@AmDiabetesAssn)