What is Continuous Glucose Monitoring (CGM)?

girl with cgm monitor

Oh, what we wouldn’t give to say goodbye to the finger stick frenzy and hello to a diabetes management experience that doesn’t feel like a full-time job. Great news! 

There’s an option out there that allows you to check your blood sugar without having to prick your finger: continuous glucose monitoring

Continuous glucose monitoring (CGM) is a technology designed to track glucose levels in real-time day or night. CGM has truly revolutionized the way individuals manage diabetes. 

Can it really simplify diabetes management by providing a convenient and comprehensive understanding of glucose patterns? 

What is CGM?

Continuous glucose monitoring (CGM) can provide a more comprehensive and immediate understanding of glucose fluctuations compared to traditional methods such as finger stick testing.

Unlike traditional blood sugar monitoring methods, CGM offers a continuous stream of data throughout the day and night. Instead of a snapshot of your glucose levels, you can see trends over time and get a better understanding of your fluctuations. 

Say goodbye to numb fingertips and constant finger pricks. 

How does CGM work?

Continuous glucose monitoring involves the use of a small sensor that is typically inserted under the skin, usually on the abdomen or arm. 

The cannula penetrates the top layer of skin and is kept in place by an adhesive patch. This is designed to stay in place for several days (most change their sensor every 7-14 days). 

The sensor estimates glucose levels every few minutes by measuring the interstitial fluid—the body fluid between your blood vessels and cells, which correlates with blood glucose levels. The result is real-time monitoring. 

It is considered an estimate as there can be a lag between the interstitial fluid (ISF) levels and the actual blood glucose levels. So, the numbers may not be entirely accurate, but they’re pretty close. It’s also possible that your device may also incorporate algorithms to adjust for the lag so the readings are more precise. 

The glucose level is transmitted to a smartphone app, an insulin pump, or a receiver, where you can view trends, set alarms, and view your glucose levels with ease. 

Benefits of CGM

Using a continuous glucose monitoring (CGM) device offers a range of benefits for individuals managing diabetes. Here are several advantages associated with the use of CGM devices:

Real-time monitoring

CGM provides real-time information about blood glucose levels, allowing users to monitor changes and trends day or night so they get continuous insight into their fluctuations

Improved blood sugar control

By receiving immediate feedback on glucose fluctuations, users can make timely adjustments to their insulin doses, diet, and activity levels, contributing to better overall blood sugar control. Viewing trends can help users make long-term decisions as well. 

Reduced risk of hypoglycemia and hyperglycemia

CGM devices can alert users to impending low blood sugar levels, reducing the risk of hypoglycemia (dangerously low blood sugar), or high blood sugar levels, reducing the risk of hyperglycemia (dangerously high blood sugar). 

This early warning allows for prompt action, such as consuming a snack or adjusting insulin dosages. The apps will also let you set customizable alerts and alarms to make monitoring even easier. 

Improved quality of life

CGM reduces the need for frequent finger stick tests, offering a more convenient and less intrusive method of monitoring blood sugar levels. It provides a sense of security and enables users to make more informed decisions about their lifestyle choices. 

CGM encourages individuals to take an active role in managing their diabetes by providing them with the tools and information needed to make informed decisions.

Risks and limitations of CGM

While continuous glucose monitoring (CGM) devices offer plenty of benefits to users, it’s not without its risks. 

Risks of CGM

The sensor is inserted into the top layer of skin, which comes with risks. Users with type 2 diabetes may be familiar with these risks thanks to the subcutaneous injection medications (like semaglutide) often used to manage type 2 diabetes.

  • Skin irritation: the adhesive patch used to keep the sensor in place can cause skin irritation or even allergic reactions. It is recommended that users rotate the location of the sensor to prevent skin irritation. 
  • Infection: inserting the sensor under the skin carries a small risk of infection, although this does not happen often. Always follow proper protocol when inserting and removing the sensor and practice proper hygiene to prevent infection. 
  • Bruising or bleeding at the insertion site: some individuals may experience bruising or bleeding at the site where the sensor is inserted. Ensure that you are following the proper insertion techniques to try and avoid this issue. 

Limitations of CGM

While CGM devices are considered extremely beneficial, there are, of course, limitations to consider. 

  • Calibration requirements: some CGM systems require periodic calibration, usually through traditional finger stick testing. Calibration helps ensure the accuracy of the CGM readings. 
  • Lag in readings: CGM measures glucose levels in the interstitial fluid, which, as mentioned above, may have a slight lag compared to blood glucose levels. Many devices have built this lag into their algorithm to ensure that estimates are as accurate as possible, but they may never be perfect. 
  • Cost: CGM devices can be expensive, with costs often totaling several hundred per month, and not all individuals may have coverage under their health insurance or access to insurance coverage. 

Who can benefit from CGM?

Blood glucose monitoring devices are most often associated with type 2 diabetes, but CGM can benefit individuals with type 1 diabetes, prediabetes, gestational diabetes, and other medical conditions as well. 

People with type 1 diabetes

Some benefits of CGM are universal: real-time monitoring, trend analysis, and improved A1c levels for instance. But, those with type 1 diabetes can manage their blood sugar levels more effectively, reducing the risk of complications associated with the condition. 

  • Reduced risk of hypoglycemia: CGM can help reduce the risk of hypoglycemia (low blood sugar) by providing warnings when blood glucose levels are trending downward. 
  • Optimal insulin management: not only can the CGM sensor transmit data directly to an insulin pump, users can see how specific foods, physical activity, and other factors affect their glucose levels with trend analysis. This information allows for personalized and optimal insulin management. 
  • Reduced risk of long-term complications: by maintaining better control over blood sugar levels, individuals with Type 1 diabetes may reduce their risk of long-term complications caused by their diabetes. 

People with type 2 diabetes

Real-time monitoring with nearly immediate feedback allows those with type 2 diabetes to quickly make adjustments to their diet, exercise, or medication regimens. 

  • Identifying glucose patterns: CGM enables the identification of patterns and trends in blood sugar levels over time. Recognizing patterns can help users make adjustments in real-time and long-term. 
  • Reduced burden: by eliminating the need to constantly prick your fingertips for finger stick testing, diabetes management feels less like a full-time job. More than that, it can actually improve adherence to monitoring routines by simplifying the process and making it more convenient. 
  • Reduced risk of long-term complications: similar to type 1 diabetes, those with type 2 diabetes using CGM can improve their A1c and glucose fluctuations, reducing the risk of potentially dangerous long-term complications related to the disease. 

People with prediabetes

Those with prediabetes have not quite reached full-blown diabetes, but they are dancing in the danger zone. CGM for non diabetics still makes sense. Continuous glucose monitoring (CGM) can actually be a valuable tool for individuals with prediabetes.

  • Early detection of glucose abnormalities: CGM allows individuals with prediabetes to establish a baseline understanding of their blood sugar levels throughout the day. It can also make them more aware of how their current habits impact their glucose levels and start taking preventative measures. 

Pregnant women with gestational diabetes

Pregnancy brain is a real thing. Adhering to a schedule of consistent finger stick testing can be difficult. Not to mention the added stress of constantly monitoring your blood sugar levels on top of everything else. 

The real-time monitoring and alerts can alleviate a lot of the stress while improving overall glucose levels. 

  • Reduced risk of maternal complications: keeping glucose levels under control can reduce the risk of complications for the pregnant woman, including gestational hypertension, preeclampsia, and other maternal health issues. Those with GDB may also deal with macrosomia (excessive birth weight)—think nine pounds or higher!
  • Reduced risk of fetal complications: high glucose levels can impact the baby’s health too. They are at risk of preterm birth, hypoglycemia after birth, and a higher risk of many health issues

People with other medical conditions: CGM for non diabetics

Continuous glucose monitoring (CGM) can be beneficial for individuals with various medical conditions beyond diabetes, such as cystic fibrosis, sickle cell disease, and adrenal insufficiency.

  • CGM for cystic fibrosis: cystic fibrosis-related diabetes (CFRD) is a common complication. This is a unique type of diabetes that could benefit from the real-time monitoring of CGM. 
  • CGM for adrenal insufficiency: individuals with adrenal insufficiency often take corticosteroid medications, which can influence blood sugar levels. CGM provides real-time data on how stressors impact blood sugar levels, aiding in more proactive management.

Comprehensive and convenient diabetes management

The continuous monitoring offered by CGM provides real-time insights into glucose fluctuations but also empowers individuals with diabetes to make informed decisions about their lifestyle, medication, and overall well-being.

Take control of your diabetes with CGM. Meet with a CGM doctor and see if continuous glucose monitoring is right for you. Get started today!


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