CGM for Diabetes and Effect on Sleep Apnea Control

If you have sleep apnea, there’s a good chance you also have Type 2 diabetes – and being overweight is a risk factor for both conditions. With diabetes, it’s important to keep blood sugar (glucose) levels under control – or risk damaging inflammation to vital blood vessels, nerves and organs.

A fingerstick has long been the traditional method to monitor blood sugar levels for diabetics. However, the advent of CGM for diabetes means you can now continuously monitor glucose levels rather than rely on a single fixed reading from a fingerstick. 

This real-time reading allows you to better manage your diabetes -- and helps control other health conditions linked to the condition such as obstructive sleep apnea.

What Is CGM for Diabetes?

CGM stands for continuous glucose monitoring and this accurately summarizes this advance in diabetes management. You insert a sensor into your arm or abdomen; an adhesive patch ensures the sensor is held in place.

The sensor transmits readings of your glucose levels to a monitor or an app on your smartphone. Readings are usually taken every 5 minutes, providing you with a detailed picture of your glucose levels throughout the day and night.

CGM can also notify you if your glucose levels are starting to significantly rise or fall, giving you the chance to address the issue sooner than you may have done and avoiding potentially dangerous outcomes. 

This represents a big step forward in diabetes management compared to taking fixed blood sugar level readings with a fingerstick. 

This is not the only benefit of CGM as the system also offers the following advantages:

  • allows you to build a picture of how different foods and activities affect blood sugar levels
  • more convenient compared to regularly pricking your finger using the traditional fingerstick approach
  • can increase the time you spend in the healthy glucose range
  • alerts people with hypoglycemia unawareness of falling glucose levels, a potentially life-saving alert.
  • Can help you maintain safe glucose levels when exercising

CGM does require a prescription and can be expensive. As the sensors have to be replaced weekly or fortnightly and the transmitters periodically too, CGM can cost between $160 to $500 per month. Therefore, it is best to check whether CGM is covered by your health insurance provider.

How CGM Could Help Control Sleep Apnea

Without proper management, diabetes can worsen the symptoms of sleep apnea -- and sleep apnea can worsen diabetes. This symbiotic relationship means that better managing your diabetes with CGM could also help control sleep apnea.

Obstructive sleep apnea (OSA) is the more common type of sleep apnea and sees breathing pauses caused by the collapse of the soft tissues in the throat while sleeping. 

The presence of OSA is high among diabetics with over 50% of those with diabetes 2 also experiencing OSA symptoms. These symptoms include

  • frequently waking from sleep
  • waking gasping for air
  • snoring
  • daytime fatigue
  • morning headaches
  • irritability
  • poor concentration

Since around 80% of cases of OSA go undiagnosed, anyone with diabetes recognizing these symptoms should consult their healthcare provider about participating in a sleep study to test for the disorder. 

How Obstructive Sleep Apnea Impacts Diabetes

It is key to know whether you have sleep apnea as managing the sleep disorder will help you better manage your diabetes. 

The breathing pauses caused by OSA reduce the levels of oxygen in the blood and increase levels of carbon monoxide. This increase in carbon monoxide in the blood leads to insulin resistance and increased levels of glucose. 

Sleep apnea is seen as a contributing risk factor for diabetes and the higher the severity of OSA the poorer your ability for glucose control.

A primary treatment for OSA is positive airway pressure (PAP) therapy. This uses a device to deliver pressurized air to a mask worn overnight that helps keep the airways free of obstruction. Therefore, the breathing pauses are quieted and blood/oxygen levels remain normal. 

As PAP therapy prevents higher carbon dioxide levels in the blood, it also prevents insulin resistance. Therefore, by managing sleep apnea you can better manage your diabetes overnight. 

In turn, monitoring your glucose levels overnight using CGM can alert you to any high drops or rises in your blood sugar levels. Reviewing your data may also reveal spikes in glucose that alert you to any breathing pauses overnight. 

The problem with identifying sleep apnea is the arousals from sleep are very brief and it can take a sleep partner to see the issue. Similarly, a snorer does not always know they are snoring, and another primary OSA symptom, daytime fatigue, can be written off as just a trait of a fast-paced modern way of life. Therefore, there are combined CGM and sleep apnea benefits to be gained here.

The Four Food and Drug Administration (FDA) approved CGM Systems

1. Dexcom 6

A factory-calibrated system brought to you by the company that introduced the first real-time CGM back in 2009. Sensors last for up to 10 days, while the transmitter will need replacing around every 90 days. The transmitter relays data to a mobile app.

2. Medtronic Minimed Guardian Connect

Uses smart technology to predict glucose levels and alerts users to potentially high or low levels so they can take necessary precautions. The transmitter comes with a 12-month warranty, while the sensor needs to be replaced weekly.

3. Abbot Freestyle Libre

Uses a small sensor worn on the arm which needs to be scanned for data results rather than data being automatically transmitted. Therefore, a handheld reader or smartphone app is required to read data, with the sensors replaced fortnightly.

4. Eversence Implantable CGM

A small sensor is implanted beneath the skin on the upper arm and can only be inserted and removed by a doctor. The sensor is approved for 90 days of use, which means it is the longest-lasting of the sensors of the four systems.

CGM has empowered diabetics to take more control of their diabetes management. Consistently updated data allows you to track glucose levels throughout the day and by activity. By better managing diabetes you can better control other conditions linked to diabetes such as obstructive sleep apnea.