Ways to Effectively Use Continuous Glucose Monitors

woman holding continuous glucose monitor
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Continuous glucose monitoring (CGM) has been used for over 15 years in the clinical setting—but at that time, barriers made it difficult for patients to effectively use the devices outside of their doctor's office. They generally wore the devices for several days but didn’t have access to the recorded information. Rather, the information would be downloaded by a medical professional for subsequent interpretation.

These days, patients usually own personal CGM technologies that allow them to see—and take action on—their blood glucose levels in real time. Yet, despite rapid advances in technology, many complain that it is difficult to know how to use the devices and supplied information effectively.

Understandably, adjusting to a new device can be overwhelming. You may even feel like it's not worth your time and effort, but knowing how to make the most of your CGM system may improve your overall A1C and help you better manage diabetes. It may be confusing at first, but learning to use a CGM pays off in the long run.

Here are some tips to help patients use their CGM systems to their maximum potential.

Calibrate Your CGM for Accuracy

Don’t forget to calibrate CGM technology with several daily finger stick glucose checks. The CGM data can’t be accurately interpreted unless this is done. The CGM sensors measure glucose levels in the interstitial fluid (the fluid that bathes and surrounds cells) rather than in blood, and this inevitably leads to a loss of accuracy.

Calibration helps minimize inaccurate reporting.

Track Your Diet and Day-to-Day Events

Even though CGM is sophisticated, it should not replace log book records. Lines on a graph are often meaningless if your doctor doesn’t know that blood sugars rose because you were at a restaurant and forgot to take your insulin or because you were stressed about an upcoming exam.

Periods of illness and stress should be documented whenever possible.

You should also note alcoholic intake, including type of alcohol and amount. Alcohol initially leads to hyperglycemia due to the sugar content in the drink but may also lead to delayed hypoglycemia.

Knowing what's going on in your life will help you and your doctor better understand fluctuations in your blood glucose numbers and make appropriate changes to your medication routine. If you don't like the old-fashioned pen and paper approach, keep a log on your computer or find an app to help you log.

Track Your Exercise

Don’t forget to use event markers record exercise sessions. In addition, if possible, mark down the type of exercise performed, since aerobic exercise tends to lower blood glucose levels while anaerobic exercise can actually raise blood sugar levels.

Tackle Nocturnal Hypoglycemia

In my opinion, the most important information derived from CGM is the detection of recurrent overnight hypoglycemia. Low blood sugars can lead to seizures and worse and should be targeted first and foremost. One should always first try to eliminate nocturnal hypoglycemia before tackling other issues, such as daytime hypoglycemic or hyperglycemic excursions.

Use the Info to Make Informed Choices

The sensor daily overlay/daily trends report shows the glucose levels for each day within a certain time period superimposed upon one another. This allows for the identification of trends which occur at the same time each day.

For example, perhaps sugars are consistently rising after breakfast. This implies that the insulin to carbohydrate ratio should be increased for breakfast. Similarly, the overlay may show low blood sugars overnight every night, in which case, perhaps the basal insulin dose should be reduced.

The daily summary/glucose trends report allows the user to look at each day individually to carefully assess the effects of diet, exercise, alcohol, stress, and illness on glucose levels.

Are certain meals more likely to cause hyperglycemia than others? This is obviously particularly helpful if you keep a diary so that patterns can be linked to habits.

Your doctor can help you better analyze these trends. Make sure to discuss changes to your medications before making any on your own!

Hopefully, these tips have been helpful. In the right setting, CGM can be a powerful tool for reducing hemoglobin A1C, while also preventing hypoglycemia. 

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