A brief overview of continuous glucose monitoring (CGM)
Continuous Glucose Monitoring (CGM) is a diabetes management tool that tracks blood glucose levels. Its fundamental departure from traditional blood glucose monitoring, which offers singular and static readings, lies in its ability to provide a continuous stream of data, sampled at regular intervals ranging from 5 to 15 minutes.
The mechanics of CGM are founded on a diminutive sensor discreetly inserted under the skin. This sensor gauges glucose levels within the interstitial fluid, painting a dynamic portrait of a person's metabolic ebb and flow. This sensor is linked to a transmitter, orchestrating a wireless relay of this crucial data either to a dedicated receiver or a smartphone application. The receiver or app renders real-time glucose data and insightful trends.
CGM provides valuable information about how food, movement, medication, and other factors affect glucose levels. This helps people with diabetes make informed decisions.
Importance of managing blood glucose levels and how CGMs can help
Trials studying the use of continuous glucose monitors in people with diabetes have shown improvements in A1c, time in range, and overall quality of life. Even just within the first 3 months of use, CGM therapy correlates with improvements in psychosocial outcomes and improved HbA1c levels for people with T1D and T2D3.
A three-year, real-world clinical trial—the longest CGM outcome study to-date—reiterates the clinical impact of using real-time CGM (RT-CGM). Study participants with T1D using CGM showed significantly reduced A1C levels, increased TIR (70-180 mg/dL), and decreased time below range (<70 mg/dL), independent of insulin delivery method1.
The benefits of CGM therapy don’t just apply to people with type 1 diabetes. Patients with T2D on mealtime insulin achieved an average 1.4% A1C reduction after using CGM therapy for 12+ weeks2, allowing type 2 diabetes patients to better meet their target A1c goals.
Meeting A1c goals can help people with diabetes maintain their health longer and live better lives. Having a more comprehensive picture of blood sugar trends can improve quality of life by helping people with diabetes feel more confident in their decision making and medication dosing strategies.
Introduction to the Dexcom G7
Approved by the U.S. Food and Drug Administration (FDA) in 2002, the Dexcom G7 is the latest iteration in the Dexcom line of CGM devices. Its approval marked a significant milestone in diabetes technology, further enhancing the precision and convenience of glucose monitoring for individuals with diabetes. As of the current writing of this article in September 2023, the Dexcom G7 is only available in the United States. For the most current and specific availability details, visit the official Dexcom website or consult a health care professional.
Key features and benefits of the Dexcom G7
Here are the current key features of the Dexcom G7 as advertised by the manufacturer:
Enhanced Accuracy and Precision: Improved sensor technology for highly accurate glucose readings.
Compact and Streamlined Design: Compact sensor and transmitter for enhanced comfort and discreet wear.
Real-Time Glucose Data on Smart Devices: Seamless integration with smart phones and other devices for real-time glucose monitoring and alerts.
Customizable Alerts and Alarms: Personalized alerts for high and low blood glucose levels to assist with timely interventions.
Interoperability and Connectivity: Interoperability with diabetes management apps and devices, facilitating comprehensive health tracking.
Improved User Interface and Experience: Intuitive and user-friendly interface for easy navigation and understanding of glucose data.
Remote Monitoring and Sharing Features: Ability to share glucose data with caregivers or healthcare providers remotely for better support and management.
Water-Resistant and Durable: Ability to withstand exposure to water, making it suitable for various activities and lifestyles.
Dexcom G7 vs Dexcom G6 (the previous model)
The Dexcom G7 boasts some pretty significant improvements to it’s predecessor, the Dexcom G7. Take a look at this comparison of the two:
My personal experience and Dexcom G7 Review
I wore the Dexcom G7 for a total of 20 days, utilizing two separate sensors. My intention was to provide a comprehensive Dexcom G7 review from the perspectives of a CDCES, RN, and my lived experience.
Anticipation surrounded the release of the Dexcom G7 system due to its promising new features. This included a grace period and alarm snoozing, both of which were much-needed improvements.
But, I regret to report that, based on my experience, I cannot recommend this system to my clients. In my professional and personal opinion, Dexcom rushed this launch. This has resulted in critical issues and bugs that impact the system's performance and reliability.
While every individual's experience with a medical device can be unique, it's disheartening to note that my issues are not isolated. Similar concerns have been echoed by my clients and various members of the diabetes online community, raising valid doubts about the readiness of the Dexcom G7 system for widespread use. For a detailed account of my experience and a more in-depth exploration of my thoughts, I invite you to watch my comprehensive video on YouTube.
Pros and Cons
Here is my personal list of pros and cons:
Compact Size: As an individual managing ADHD and juggling the responsibilities of a travel RN, efficiently packing my medical supplies for frequent cross-country trips is essential. The compact design of the Dexcom G7 stands out as a significant advantage in this regard. Not only is the profile smaller when worn on the body, but the packaging itself is streamlined, making it exceptionally convenient for travel. One notable feature that particularly appealed to my executive function challenges is the elimination of the separate transmitter. The simplified process of placing the sensor made a significant difference for someone like me with ADHD, enhancing overall user-friendliness. Additionally, the G7's commitment to reducing environmental impact is commendable, with a 20% reduction in plastic usage, contributing to a decrease in medical waste. While this is a positive step, I look forward to Dexcom's continued efforts to further minimize their ecological footprint. The Grace Period: I mean, we all know that the sensor never expires during a convenient time. You’re almost always getting ready for bed or driving down the highway when the sensor decides to combust. The Dexcom G7 totally eliminates this pain point with a 12 hour grace period that allows you to push the life of the sensor until a more convenient time. This was a total win for me. Dexcom G7 App: The app was much more user friendly and streamline. I also loved that you could see your time in range right from the main app instead of going to the Clarity app. The G7 app also makes it way easier to input events as well as change your alert settings. It’s a fantastic improvement from the G6’s minimal setup. Delay First Alert and Alarm Snooze: Few things rival the anxiety induced by the relentless blare of an urgent low alert. It pierces through the already stressful situation of dealing with a low blood sugar. As anyone managing diabetes knows, the chosen treatment for a low typically takes a good 15-20 minutes to show any effect, all the while enduring the incessant clamor from the Dexcom. Thankfully, the Dexcom G7 comes to the rescue with its snooze feature, allowing users to acknowledge the urgent low and silence the persistent alerts. This simple addition significantly alleviates the stress, improving the overall daily experience for individuals managing diabetes. Furthermore, the introduction of the "Delay 1st Alert" feature is a game-changer. Especially after a meal, blood sugar levels tend to rise. Being bombarded with alerts at these times can be overwhelming and unnecessary. This feature empowers users to postpone the initial high alert, sparing unnecessary insulin dosages and greatly reducing stress levels.
Regular Signal Loss: Personally, the Dexcom lost signal so much for me and so consistently, that is actually interfered with it’s functionality. There was no rhyme or reason for the signal loss as it would happen even when the phone was right by the sensor. Noise and Lack of Back Smoothing: This was huge. The graphs and trends were so erratic that it actually made it dangerous to use with a hybrid closed loop algorithm. While I am using a non-FDA approved AID system, this is still troubling and makes me question whether this will be possible to use with any commercially available AID systems like Control IQ and Omnipod 5. This is typically referred to as “noise.” Currently, Free APS X has a feature that allows for adjusting when the noise of your sensor is particularly bad. This helps to minimize risk for over and under dosing. Commercial algorithm will need to consider adding this or Dexcom will need to improve their sensor. Please take a look at this article to see a more in depth explanation of why this was problematic. Not safe for dosing decisions: Most of the time, my sensor was more than 20% off which to me is totally unacceptable. I know there will be variances but this is far worse than the G6. Again, my own personal experience, however, this is not an uncommon complaint amongst users. As a health care provider, I cannot enthusiastically recommend this for my insulin using clients. And, honestly, I’d rather recommend the Libre 3 over the Dexcom G7 to those who don’t use insulin/rely on it for dosing. List Price: No adjustment was made to the list price despite the smaller size. In fact, it is a similar size to the Libre but the list price is significantly more. I’m disappointed in Dexcom (yet again) for choosing profits over patients.
I had extremely high hopes for the G7. The allure of its new features and potential benefits was significant. But it's disheartening to discover that the G7's overall functionality overshadowed all the promising improvements.
I'm optimistic that Dexcom will swiftly address the signal loss and sensor noise concerns through updates, allowing us to confidently transition to this system and fully embrace its potential.
Šoupal J, Petruželková L, Grunberger G, et al. Glycemic Outcomes in Adults With T1D Are Impacted More by Continuous Glucose Monitoring Than by Insulin Delivery Method: 3 Years of Follow-Up From the COMISAIR Study. Diabetes Care. 2020;43(1):37-43. doi:10.2337/dc19-0888
Champakanath A, Akturk HK, Alonso GT, Snell-Bergeon JK, Shah VN. Continuous Glucose Monitoring Initiation Within First Year of Type 1 Diabetes Diagnosis Is Associated With Improved Glycemic Outcomes: 7-Year Follow-Up Study. Diabetes Care. 2022;45(3):750-753. doi:10.2337/dc21-2004
Gilbert TR, Noar A, Blalock O, Polonsky WH. Change in Hemoglobin A1c and Quality of Life with Real-Time Continuous Glucose Monitoring Use by People with Insulin-Treated Diabetes in the Landmark Study. Diabetes Technol Ther. 2021;23(S1):S35-S39. doi:10.1089/dia.2020.0666