Continuous Glucose Monitoring: A Major Advance in Blood Sugar Control

| Sep 9, 2007

Life in the trenches with type 1 diabetes is challenging. Unpredictable blood sugars can leave a person with diabetes (PWD) feeling frustrated and helpless. The acute toxic effects of abnormal blood sugars also contribute to depression, anxiety, irritability, and food cravings.

Every PWD knows that the primary goal in managing diabetes is to keep blood sugar levels as close to normal as possible. Unfortunately, one of the "rewards" for those who work hard to control their blood sugar is an increase in low blood sugar attacks, or hypoglycemia.

These occurrences can be frightening, embarrassing, and dangerous. Avoiding low blood sugar attacks generally means keeping blood sugars higher. But higher blood sugars bring with them the proverbial dark cloud of complications.

Advanced treatment programs, like those taught by Dr. Richard Bernstein, have made relatively normal blood sugar levels attainable and much safer. Limiting total carbohydrate intake, matching carbohydrates with precise use of insulin, and frequent blood sugar monitoring have all made it easier and safer to maintain normal sugar levels.

But no matter how motivated a person is or how well a diabetes program works, maintaining tight control of blood sugars always has its teetering tightrope moments. And unexpected blood sugar spikes and drops feel like undeserved cheap shots. Every PWD has many times said in frustration: "What the hell is this and where did it come from!" after checking blood sugar levels.

Maintaining "normal" blood sugar levels requires a PWD to think and act like a pancreas. To achieve this, it's important to be able to react appropriately to changing blood sugars before they reach abnormal ranges. High and low blood sugar levels do not show up out of nowhere. Abnormal outcomes are the product of transitions over time.

Unless we can see these transitions and trends in progress, we cannot preempt and prevent abnormal blood sugars. Outside of checking blood sugars many times an hour, every hour of every day and night, it has not been possible to track blood sugar levels, trends, and patterns at all times. Not having "in-time facts" about sugar trends and patterns has made it difficult to accurately play the role of a pancreas.

But now continuous glucose monitoring (CGM) is making it possible. A company called Dexcom, Inc., of San Diego, California, has developed a monitoring system able to provide ongoing body sugar measurements without repeated finger or arm sticks. The system measures body sugar levels every five minutes, twenty-four hours a day, and wirelessly sends the data to a pocket monitor. This adds up to 288 blood sugar checks per day.

Dexcom's CGM system is set up to alert the wearer when blood sugar levels rise above or drop below preset sugar-level limits. This enables the wearer to identify, preempt, and prevent undesirable high and low blood sugars. The CGM system provides a safety net that prevents being blind-sided by low blood sugar hits and unexpected highs. This safety net is especially important for anyone who experiences hypoglycemia during sleep and for those at risk of low reactions when driving a vehicle.

The wireless monitor has a screen that shows blood sugar trends on a graph over time, making it easy to see what is happening and where things are likely going. Thus, the CGM makes it much easier to make accurate adjustments and play the role of a pancreas.

Set-up and use of the CGM is easy once the process is learned. It is not a completely non-invasive system. It requires the insertion of a small and flexible piece of metal under the skin. The inserted metal and an attached sensor stick to the surface of the skin. The sensor insert needs to be replaced weekly. The system also requires calibration, involving at least two finger sticks per day. Calibration is required to maintain the accuracy of the sugar readings.

The portion of the sensor under the skin is in contact with interstitial fluid, not blood. Interstitial fluid sugar levels adjust approximately fifteen minutes after changes have occurred in blood sugar levels. So there is a small delay in the real-time accuracy of the system. But this issue does not interfere with the use of the Dexcom as a life-enhancing information tool and safety net.

Dexcom's CGM system is the first generation of a relatively new technology, and new technologies always have room for improvement. One problem with the Dexcom system involves the low blood sugar warning system. Because interstitial fluid sugar levels rise more slowly than blood sugar levels, the low blood sugar warning system is slow to adjust to corrections.

After appropriate correction for a low sugar is made, the low blood sugar alarm on the meter continues to go off every five minutes until interstitial sugar levels normalize. This delay can be annoying, especially during the night, or can cause a person to over-compensate with dextrose or other blood sugar raising foods.

At some point in the future, the meter portion of the system will likely shrink down to the size of a small watch. As the manufacturer recoups its initial investment costs, hopefully the monthly costs of replacement supplies will go down enough to allow a majority of PWDs to use this technology. Currently, costs add up to around $240 per month for supplies, on top of an initial $450 for the meter itself.

Besides a few fixable flaws, the overall technological design, accuracy, and function of this first generation system is quite remarkable. The entire Dexcom system is designed and manufactured within the USA. Kudos to the creative technologic design teams at Dexcom.

Steven K. Gordon, ND, is a Naturopathic Physician who has had type 1 diabetes for over 25 years and has maintained an A1c of less than 5.5 % for the past ten years. Dr. Gordon has spent his professional life studying the biological factors that promote quality of life and health, contrasting them with the factors that cause aging, chronic disease, and diabetes. With his unique medical perspective, Dr. Gordon utilizes treatment protocols that re-establish and maximize health, body maintenance, and healing potentials. It is his conviction that while prescription drug treatments are essential for most people with diabetes, many other non-drug biological and metabolic factors have equal importance in improving health and preventing disease complications. When these factors are overlooked, quality of life, overall health and long-term outcomes are less than optimal. Certain forms of diabetes are actually curable, while other more difficult forms can be treated in ways that improve quality of life at all levels in the short and the very long-term. Diabetes, says Dr. Gordon, need not be feared.

Dr Gordon is in the process of finishing his first book, Understanding Metabolic and Blood Sugar Disorders - A Health Restoration Guidebook, which is due out in early 2008.

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Categories: A1c Test, Beginners, Blood Sugar, CGMs, Diabetes, Diabetes, Food, Insulin, Low Blood Sugar, Professional Issues, Type 1 Issues

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Posted by BillRuss on 14 December 2007

Applause to DocG for his very insightful article, but I must object to the use of the term "Low Blood Sugar ATTACK." In my view that is almost as bad as calling it a "SIEZURE." The term "reaction" seems much better to me if we muc avoid the proper term "hypoglycemic event."

Posted by Anonymous on 28 December 2007

How do you convince insurance companies to cover the cost of the continuous glucose monitoring systems and encourage doctors to help you convince insurance companies to cover it?

Posted by Anonymous on 17 January 2008

I have been diabetic for 25 years. Before my Minimed pump, I was in the hospital 6 times for hypoglycemic siezures. I then went the other way and kept it too high all the time. I have Medtronic sensors and now am on Dexcom's system. Dexcom is much better for me. Much more accurate. Now my A1C is 5.7 with very few lows. The article mentions that the reading on the CGMS can trail by up to 15 minutes but if you are watching what you are doing and not eating or drinking things that will affect you in a sudden way, then the delay is a non-issue. This along with a pump provides the closest thing to date to a functioning pancreas.

Posted by WrightLC on 22 November 2009

The DexCom7 and Hypersensitive Sound Alarm (HSA) are things ever diabetic should own. First, I normally write a recommendation only when something is truly amazing and these products are. I've had diabetes for 30+ years and have never felt so much control over my health and well being as I do today because of these devices. A year ago, for the first ever, I lived alone. As a diabetic, I was terrified that I would die in the middle of the night from a low blood sugar episode. So, I evaluated all the continuous glucose monitors and determined the DexCom would be the best choice because it offered: 1) the loudest alarm; 2) the longest time that a sensor could be in place (7days); and 3) the cheapest cost. Although the system is amazing and has all the above benefits, its alarm is not loud enough to wake me from a deep sleep (a few low beeps which last only a few seconds). When I first got it, on several occasions, I awoke to discover that I had either been running low (30-40) for more than an hour or high (200+) for hours. I don't know how many brain cells or clogged arteries that cost me, but I knew I better find a way to increase the volume of the alarm quickly or else I could die prematurely. Luckily, I found another amazing device which amplifies the sound of the alarm so much that it even wakes me from a deep sleep. It can be used with any of the glucose monitors. You can get the HSA device from: Although it is a bit pricey - it is worth it, because it has saved my life more than once and many brain cells. Now, for the first time, I can sleep soundly and safe, because I don't have to worry that I won't be able to hear the alarm. The HSA is a must have if you live alone, travel alone, or ever sleep alone. It is also a must have for parents or caregivers of children or the elderly who don't want their loved ones to run high all night or be low for hours because you don't hear the DexCom7 alarm. It is perfect for diabetics who want tighter control of their blood sugar. Since the DexCom and other continuous blood glucose monitor alarms only go off once – then are deactivated by a touch, you can be extremely low or high for hours without knowing. This HSA prevents this from happening, because it wakes you even in deep REM sleep. These devices have easily added 10 years to my life and increased the quality of my life substantially. My insurance covered most of the cost of the DexCom7. The HSA is not covered under insurance, because it is not considered a medical device. However, both were necessary to achieve the level of safety I desired. Frankly, my life and my brain cells are worth every penny.
Laurie Wright

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