JDRF-Funded Clinical Trial Demonstrates Continuous Glucose Monitoring Improves Blood Sugar Control

September 08, 2008

Study findings presented at the European Association for the Study of Diabetes meeting and reported in the New England Journal of Medicine indicate CGM can help type 1 diabetes patients lower HbA1c levels, better control diabetes

September 8, 2008 (EurekAlert) - Patients with type 1 diabetes who used continuous glucose monitoring (CGM) devices to help manage their disease experienced significant improvements in blood sugar control, according to initial results of a major multicenter clinical trial funded by the Juvenile Diabetes Research Foundation. Results from the study were presented today during the European Association for the Study of Diabetes (EASD) annual meeting in Rome, and portions of the data will be published in the October 2 issue of the New England Journal of Medicine, available on line today at nejm.org.

The CGM study is a randomized, controlled trial involving 322 patients spanning the age range of 8 to 72 years at 10 sites, which included academic, community, and managed care based practices at the Atlanta Diabetes Associates, the Joslin Diabetes Center, Kaiser Permanente Southern California, Nemours Children's Clinic - Jacksonville, FL, the Lucile Packard Children's Hospital at Stanford University, the Barbara Davis Center for Childhood Diabetes at the University of Colorado Denver, the University of Iowa, the University of Washington, and Yale University, and coordinated by the Jaeb Center for Health Research in Tampa, Florida. Patients were assigned to either CGM or a control group using standard blood sugar monitoring and were followed for 26 weeks to assess effects on blood sugar control, principally assessed by measurement of the HbA1c level. At enrollment into the study, patients had HbA1c levels of 7-to-10% (the goal for adults with type 1 diabetes generally is a level below 7% and for children and adolescents below 7.5-8%). Three age groups were analyzed separately: 8 to 14 years of age, 15 to 24 years of age, and 25 years of age or older.

Improvements in blood sugar control were greatest for CGM patients 25 years of age or older, whose HbA1c levels decreased (improved) during the study by an average of 0.53% compared with control patients (p<0.001); improvements in secondary measurements were also significantly greater in CGM patients, including the percentage of patients able to achieve an HbA1c level below 7%, or a 10% relative or 0.5% absolute drop in HbA1c. The improvement in HbA1c occurred without an increase in hypoglycemia (low blood sugar), which is the worry when attempting to tighten glucose control. In children aged 8-14 years old, the average decrease in HbA1c was not significantly different in the CGM and control groups; however, those in the CGM group were more likely to lower their HbA1c by at least 10% and achieve HbA1c levels below 7% compared with the control group. Fifteen-to-24-year-old CGM patients, as a group did not experience significant improvements in glucose control compared with the control group.

CGM use varied with age, averaging at least six days a week over the course of the trial in 83% of the patients 25 years and older, but dropping off to 30% of the 15 to 24 year olds and 50% of the 8 to 14 year olds (for whom CGM use typically involved their parents' assistance). Although the study was not specifically designed to assess the effect of frequency of CGM use on HbA1c, an analysis presented at EASD suggested that patients within all three age groups, including teens and young adults, who used the device at least six days a week had substantially lower HbA1c levels after six months compared with patients who used CGM less than six days a week.

"These results are very important, because they show that continuous glucose monitors are more than simply devices of convenience for people with diabetes – they are tools that can substantially improve blood sugar control when used regularly," said Dr. Aaron Kowalski, Program Director for Metabolic Control at JDRF. "Based on the findings of previous studies, better control of glucose levels over the long term can be expected to translate to a lower risk of complications for people with Type 1 diabetes.

The lower levels of regular CGM use among children and teenagers observed in this study underscore the importance of continued research into a closed-loop artificial pancreas – a device that uses CGM data to administer appropriate doses of insulin through a pump without the need for involvement of the patient or for young children their parents."

Posted by dlife at 04:32 PM | Comments (0)

Critical Diabetes Test - A1C - Proven To Be Accurate Average Glucose

June 07, 2008

June 7, 2008 (ADA) - A mathematical relationship between the average glucose level over the preceding three months and levels of the A1C test, thus yielding translation of the A1C for reporting as estimated average glucose (eAG), was proven in an international study published online today in the August issue of Diabetes Care. A1C has been used for more than 25 years as the major measure of glucose control and to establish targets for diabetes therapy.

“The findings of this large study have confirmed what smaller studies have shown and will give us confidence that A1C really does represent an average glucose because we now have a reliable formula to convert A1C into average glucose,” said David M. Nathan, MD, Professor of Medicine, Harvard Medical School, and co-chair of the International A1C-Derived Average Glucose (ADAG) Study, in a recent interview. “While eAG will not replace A1C, physicians will be able to obtain reports both in A1C units of glycated hemoglobin and eAG units of milligrams per deciliter or millimols per liter, depending on the country, and choose which to use in clinical situations.”

The implications of using eAG in mg/dl or mmol/L – the same units that patients use for self-monitoring
of blood glucose (SMBG) at home – were discussed recently by his co-chair, Robert J. Heine, MD, PhD, Professor of Diabetology in the Department of Endocrinology at the VU University Medical Center in Amsterdam, Netherlands, and Executive Medical Director of the Diabetes and Endocrine Division of Eli Lilly and Company.

“It is extremely helpful for health care professionals and patients to be using the same language to discuss glucose goals,” said Dr. Heine. “Since patients sometimes find it difficult to understand the concept of glycated hemoglobin, it will be much easier to have all test results – both those from the lab and those the patient performs – in the same units.”

With A1C translated from a difficult-to-understand chemical entity into an easy-to-understand value that relates to the patient’s every day home glucose monitoring, Dr. Heine predicts that eAG will prove to be a valuable education tool.

“When health care professionals set goals based on eAG units, then patients will know how close they are to reaching their goals every day when they test at home with self-monitoring,” said Dr. Heine.

Checking Blood Glucose Levels
People check their diabetes control at home by SMBG, usually by pricking their fingers for a blood sample
and getting a reading using a simple monitor. Frequency varies depending on the type of diabetes and whether insulin injections are being used. Many people with type 1 diabetes, who must use insulin, do SMBG several times a day, or use continuous glucose monitors, which automatically check levels as often as every few minutes. The test provides information on blood glucose only at that moment.

In contrast, A1C testing is a measure of glucose control over the prior 2-3 months. The test measures the amount of glucose that has attached to a portion of the hemoglobin molecule in the blood. It is reported as the percent of hemoglobin molecules that has glucose attached. The American Diabetes Association recommends a goal of less than 7%. It is also known as glycated hemoglobin testing.

The International A1C-Derived Average Glucose Study A group of international investigators conducted a 10-center study to try to define, as accurately as possible, the relationship between average blood glucose levels and A1C. The study recruited 507 volunteers of various races and ethnicities: 268 type 1, 152 type 2, and 80 without diabetes. The study measured A1Cs in a central laboratory monthly for 3 months, and measured average glucose levels using a combination of continuous glucose monitoring
and frequent self-monitoring of blood glucose levels.

"We developed an equation that can be interpreted accurately as an estimated average glucose level by
comparing the measurement of A1C with the average glucose levels,” explained Edward S. Horton, MD, Professor of Medicine, Harvard Medical School, and a co-author of the ADAG study, who will be presenting further information about the study at the American Diabetes Association’s Scientific Sessions here tomorrow. Study investigators found a simple linear relationship.

“Although the tight and consistent relationship across different subgroups suggest that, for most people, there are no important factors that affect the relationship between A1C and average glucose, the study does have some limitations,” said Dr. Horton. In contrast to their intention and expectation, some ethnic-racial groups were under-represented, particularly people of African and Asian descent. Children and pregnant women were excluded from the study, as were patients who were not in stable control or with any suggestion of red blood cell disorders. So additional data in these groups would be needed to confirm the established relationship.

The American Diabetes Association (ADA), European Association for the Study of Diabetes (EASD), and
International Diabetes Federation (IDF) will be working together to conduct educational efforts to make both patients and providers aware of this new terminology, and help to understand the relationship between A1C and AG. In the meantime, the American Diabetes Association announced that physicians can visit its Web site at www.diabetes.org to purchase a very inexpensive handheld calculator that will provide an instant conversion of A1C values to eAG.

Diabetes Care, published by the American Diabetes Association, is the leading peer-reviewed journal of
clinical research into the nation’s fifth leading cause of death by disease. Diabetes also is a leading cause of heart disease and stroke, as well as the leading cause of adult blindness, kidney failure, and non-traumatic amputation.

Posted by dlife at 02:24 PM | Comments (0)