Continuous Glucose Monitoring,
A new tool to better control your diabetes

Anyone with diabetes knows how extremely difficult it can be to maintain stable glucose levels that are within normal limits without experiencing frequent hypoglycemic episodes, even the more severe ones.

Now, this “impossible mission” is closer to becoming reality thanks to the new continuous glucose monitoring (CGM) system.

The CGM system provides continual “real time” glucose levels every five minutes around the clock allowing for viewing and storage of measurements.

What is the CGM system and how does it work?

Currently there are three commercialized CGM devices that basically consist of three parts: a transmitter, a receptor and a sensor. These “methods” utilize a fiber that contains the enzyme glucose oxidase, which is inserted underneath the skin. With the help of a simple application device, the sensor is inserted in the subcutaneous tissue. Once the calibration period has occurred, the device will send electric signals through the transmitter which then appear as glucose values on the receptor screen.

Who are candidates for using the CGM system?

Potential candidates will need to have an open mind, be capable of abstract thinking and be motivated to use new technology.

•  Almost all of the patients with type 1 diabetes would be good candidates for using the CGM system, since they run the greatest risk of hypoglycemia; particularly those who struggle with keeping their hemoglobin A1C levels below 7%. The benefits of the CGM system have been demonstrated in both of the current insulin treatment modalities. In other words, the CGM system would work with either the multi-dose insulin treatment or with the insulin pump treatment. What is the most important factor, is that the patient have the desire to use this technology.

•  The pediatric population with diabetes would be good candidates, as the CGM system significantly decreases the number of daily blood sugar measurements that are needed to ensure the child’s safety.

•  Patients with asymptomatic hypoglycemia or those that fear hypoglycemic episodes and opt for higher blood sugar levels so as to avoid hypoglycemia would be good candidates. Thanks to this new technology, this population can reach lower blood sugar levels while lowering the risk of hypoglycemic episodes.

•  Adolescents as a group have not had good results with the CGM system. In my opinion, it’s because the CGM system represents control in some way and we know that teenagers tend to “hate” any type of control. However, there are always exceptions.

•  The benefits have been demonstrated for women with type 1 diabetes who plan on getting pregnant. The benefits include mother and fetus both before and during the pregnancy.

•  Patients with diabetic gastroparesis and those with the biggest glucose variability.

•  Also, patients with type 2 diabetes who have been treated with insulin for many years and are at higher risk for hypoglycemia would be a also a good candidate for the CGM system.

Who is not a candidate?

These systems are not indicated for patients with type 2 diabetes who are not treated with insulin. Nor are patients with type 2 diabetes who do use insulin but have stable blood sugar levels and have a low risk for developing hypoglycemia.

People who will get frustrated with the alarming system of the device or those that become anxious about inserting the sensor, managing the calibration, or those that are not capable of using the information provided by the device (not just the minute by minute information but also the glycemic trends or those that will not learn from their mistakes or imperfections of the actual system itself. It has also been demonstrated that patients whose family don’t support the CGM system would not benefit from this technology.

The CGM system allows you to:

•  Optimize basal trends and insulin boluses in patients with insulin pumps and suboptimal hemoglobin A1C levels.

Determine the changes in the insulin sensitivity factor or the carbohydrates insulin ratio.

Observe post prandial glucose trends to certain foods throughout the day and finding the best time to inject a bolus of insulin for each food and quantity of carbohydrates. In addition, the CGM system helps modify eating habits.

Take note of the blood sugar trends 10-12 hours after having done exercise.

Identify nocturnal hypoglycemic episodes or low blood sugars at dawn.

Act on time to minimize the peaks and lows of the blood sugars levels.

Practical considerations

•  As in all aspects relating to the treatment of diabetes, education is fundamental in order to achieve success with the CGM system. In addition, one should thoroughly familiarize themselves with the equipment.

It is important to download and analyze the data to the computer at least once a week. This is especially important as it will facilitate a realistic expectation and in turn help to avoid obsessing about excess information.

Follow the operating instructions included with the device.

Always consider the delay times between the glucose values of the interstitial fluid and the blood, which usually fluctuates between 6-20 minutes, but can be a bit longer when the blood sugar values are rapidly changing. On the other hand, when blood sugar values are more stable, the glucose numbers between the device and blood measurement are more similar. Nevertheless, there may be behavior differences between different monitor devices.

Above all, one should pay “attention” to the trends and not put so much importance on the device’s current glucose value.

In the beginning, so as to avoid being overwhelmed by the device’s alarm, the objective settings should be broadened. Once you become more familiarized with the technology, the alarm settings can be adjusted and fine-tuned.

Avoid overreacting to the alarm (for example, if you’re going to give yourself a supplemental dose of insulin as a result of a high glucose reading that occurs one or two hours after having treated a hypoglycemic episode, you could worsen the situation and cause another episode of hypoglycemia.

The insulin treatment changes should be based mainly from the blood glucose readings.

The recommended time to look at the device is every 20-30 minutes when blood sugar levels are stable.

Avoid taking Paracetamol, as the glucose readings will be falsely elevated for several hours.

It recommended that you write your name and telephone number on the back of your CGM device in case of robbery or loss. This will increases the chances of recovering the device.

There’s no doubt that the technology of the CGM system will continue to improve and revolutionize the current diabetes treatment. The devices will become smaller, less frequent need to calibrate the device, the communication capabilities and data transmission could be included in a typical “iPhone” and the cost of the device will decrease. The data will be sent and stored “on the cloud” In the meantime, certain groups of diabetes patients may benefit and in the near future we hope the majority of patients with diabetes benefit.
Dr. Ramiro Antuña de Alaíz

Endocrine Educator
Gijón, Asturias

Translation: Sarah Folan
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