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

We received this VERY IMPORTANT press release from JDRF yesterday.

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

New York, NY, September 8, 2008 – 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."

About Type 1 Diabetes
Type 1 diabetes is an autoimmune disease that affects children, adolescents, and adults, in which the immune system attacks cells in the pancreas that produce insulin, a hormone that enables people to convert food into energy. People with type 1 diabetes are dependent on insulin for the rest of their life. But insulin is not a cure, and people with diabetes are at significant risk for a wide range of serious complications, including heart disease, blindness and kidney disease. As many as 3 million people in the U.S. have type 1 diabetes.

About CGM Devices
CGM devices, manufactured by several companies and approved by the FDA as an adjunctive therapeutic for diabetes, provide both a real-time snapshot of the glucose levels of a person with diabetes, as well as trend information on whether glucose is moving upwards or downwards, and how fast. Devices also provide warnings when the glucose is becoming too high or too low.

I would love to hear from folk that find it perhaps easier to simply know where your sugars is going and how fast so you can make a correction prior to a crash or a spike, via a shot. seams to make sense to me. Before they had CGM’s my endo doctor and I had heated discussions… my claim was tell me where I’m going and I can correct. the Pump, though a great tool especially with the bolus wizards and all that, does not tell me of an impending crash… Please chime in how many T1’s taking shots are managing their BS with the CGM.


Actually, I think the JDRF study showed a .5% glycated hemoglobin decrease in association with CGM therapy. That improvement would not, in my humble opinion, clinch the case favoring use of CGMs. I think it most likely that such modest improvement could be replicated, if not improved upon, by increasing frequency of conventional finger-stick tests.

Amongst other problems,I find the ‘real time’ characterization of CGM glucose values to be off the mark. There are no clear algorithms by which to convert interstitial glucose values into pasma glucose values. The relationships, as a matter of physiology, are highly variable. It is not even the case that plasma values clearly lead interstitial glucose values – as in the case of vigorous exercise. These unclear relationships are exacerbated byimperfect CGM measurements especially in the presence of glycemic fluctuations. One should not rely on CGM values as a basis for interventions as such reliance could give rise to lethal consequences. I am especially skeptical about use of CGM as basis for a closed-loop system of insulin delivery (except, perhaps, for the most minimal closures of the loop.)

This article excerpt gives me some hope that endo.'s and insurance co.‘s will someday soon “see the light” at the end of the diabetic tunnel and grant us the right to a CGM as another tool we deserve and should have to help control our disease. I was turned down by my dr. for a CGM as my case was not "extreme"enough and the insurance co. wouldn’;t approve it – sadly, this is true, I know – and then even got rejected by the insurance co. for a simple sensor to be added to my MiniMed pump to help stabilize my BG, which fluctuates pretty wildly after over a yr. of efforts to control it and bring it on target. I plan to share this article with my dr. at my next appt. Wish me luck!

Your reply was informative and interesting…I am one of those “T1” people who have to “stick my finger” about 18-20 X / day just to keep on top of my wildly fluctuating BGs. I’m just curious – do you need to test often?
Or, do you have an already ‘stable’ BG?

I use Minimed’s CGMS and I love it. I have lowered my A1c from 10.3 to 6.8 in one year by going on the pump and using the CGM. I had big swings in my BGs as well. I can’t tell if my BG is hi unless I’m over 300 and I can’t tell if I’m low unless I’m at about 30 By watching the CGM graph I can tell if my BGs are starting to trend in one way or another. This doesn’t replace finger sticks, but it cut them WAY down. When I went on the pump I was like you. Testing 15-20 times a day. When I got on the CGM that went down to about an avg of 7. For the MM version of the CGM you have to calibrate it every 12 hours at a minimum. I usually do it 3 sometimes 4 times a day. Once when I get up in the morning, right before lunch, and right before I go to bed. Those, generally speaking, are the most stable times for BGs. Every now and then the reading is a little too far off around supper time so I throw in a calibration then. The thing to remember is that the whole purpose is to see trends. It really helped me see what my BGs were doing when I was trying to get my basals nailed down.

The insurance company declining coverage is no surprise. Many of them consider it “experimental” still even though the technology has been out there for something like 5-7 years now. Are you on the pump as well? If you are then you really need to work with your endo to get those basal rates squared away. Otherwise all you are doing is chasing the BGs all over the place. If you aren’t on the pump, talk to him about it. It really helps a ton in managing your diabetes.

Your doc denied you the CGM? You may want to tell him that the CGM is not really his choice. If you think that it would help you manage your BGs then he should do it. Otherwise I would find a different doc if possible.