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Challenges With Continuous Glucose Monitoring: Connectivity, Costs, and Usability

July 9, 2024

Continuous Glucose Monitoring (CGM) systems have become a popular method for diabetes management by providing glucose readings, without the need for frequent finger-prick tests. However, despite their immense popularity, CGMs are not without their challenges. Let’s delve into some of the pressing issues that affect patients who use CGMs and providers that rely on them for accurate data. A few of these problems include Bluetooth disconnection problems, high costs, and more, with insights from a recent article on the wearable technology market.

1. Bluetooth Disconnection Issues

One of the most common technical problems faced by CGM users is Bluetooth disconnection. CGM devices rely on Bluetooth technology to transmit data from the sensor to the receiver or smartphone app. When this connection is lost, both patients and providers can miss critical glucose readings, potentially leading to unsafe situations.

Causes and Impact:

  • Interference: Bluetooth operates on a 2.4 GHz frequency, which is crowded with signals from various devices like Wi-Fi routers, microwaves, and other Bluetooth gadgets. This interference can cause frequent disconnections.
  • Distance and Obstacles: The effective range of Bluetooth is relatively short. If the user moves too far from the receiver or if there are obstacles like walls, the connection can drop.
  • Battery Life: Both sensors and receivers require adequate power. A low battery in either device can lead to connectivity issues.

The impact of these disconnections can be significant. Missing glucose data can make it difficult for users to manage their condition effectively, potentially leading to hyperglycemia or hypoglycemia. Moreover, constant connectivity issues can be frustrating, reducing the overall user experience and trust in the technology.

2. High Costs

Another major barrier to widespread CGM adoption is the high cost. CGM systems are expensive, and the price can be a significant burden for many patients, especially those without comprehensive health insurance.

Cost Breakdown:

  • Initial Setup: The initial cost includes the CGM device, sensors, and possibly a transmitter. This can range from several hundred to over a thousand dollars.
    • Dexcom G6: The starter kit, which includes a receiver, transmitter, and sensors, costs around $1,000.
    • Freestyle Libre 2: The initial cost ranges from $400 to $600 for the reader and sensors.
    • Medtronic Guardian Connect: The starter kit costs approximately $700 to $1,200, depending on the package and retailer.
    • Eversense: The initial setup, including the implantable sensor, transmitter, and other components, ranges from $1,200 to $2,500, with additional costs for the procedure to implant the sensor.
  • Ongoing Expenses: Sensors need to be replaced regularly (every 7-14 days), and transmitters often have a limited lifespan, adding to the ongoing costs.
  • Insurance Coverage: While some insurance plans cover CGMs, coverage can vary widely. High deductibles, co-pays, and limited coverage for replacement parts can still make CGMs unaffordable for many.

The high costs present a barrier to people with diabetes who are in lower income brackets, leading to  poorer diabetes management and higher long-term healthcare costs due to complications. A Forbes article highlights how these costs can push consumers away from essential health technologies, emphasizing the need for more affordable solutions. The article mentions that CGM costs range from $100 to $300 per month, covering sensors and transmitters, with most sensors lasting 10 to 14 days and requiring frequent replacements. Additionally, Some CGMs include a reader for a one-time cost of $60 to $80, which can be avoided by using a smartphone app.

3. Calibration and Accuracy

While modern CGM systems are generally accurate, they still require periodic calibration with traditional blood glucose meters. For example, an Abbott press release about Libre Rio, an over-the-counter integrated continuous glucose monitoring (iCGM) device, states "if readings do not match symptoms or expectations, use a fingerstick value from a blood glucose meter for treatment decisions." Even the manufacturer of a CGM knows that a glucose monitor that uses a fingerstick to test blood glucose levels is more accurate than a CGM.


  • Calibration Needs: Regular calibration can be inconvenient, and failure to calibrate correctly can lead to inaccurate readings.
  • Lag Time: CGMs measure glucose in interstitial fluid, not blood, leading to a lag during rapid glucose changes.

One reason for inaccuracy with CGM readings could be how they measure glucose. With traditional blood glucose monitoring, patients are measuring the amount of glucose that is present in their blood at that exact moment in time. In contrast, CGM devices pierce the top layer of skin and measures glucose in the interstitial fluid and not actual blood, which is not as accurate. Accuracy is essential for safe and effective diabetes management. Abbott's caution about their CGM reading underscores the need for providers and patients to investigate the viability of a CGM thoroughly to determine if it is the best glucose monitoring technology for a particular patient’s needs.

4. User Experience and Education

The user experience with CGMs can vary widely based on the system's design and the user’s familiarity with the technology. Lack of education and support can also cause issues for people using CGMs. When issues occur and users aren’t trained in troubleshooting those issues or have reliable customer support to help, they can grow frustrated with the technology and discontinue its use.

Key Considerations:

  • Ease of Use: Systems with complex interfaces or cumbersome sensor insertion processes can be daunting, particularly for elderly patients or those who are not tech-savvy.
  • Support and Training: Adequate training and ongoing support from healthcare providers can help users get the most out of their CGM systems. However, not all users receive sufficient guidance.

Recent Studies on Continuous Glucose Monitoring

Several recent studies have explored various aspects of Continuous Glucose Monitoring (CGM), highlighting both benefits and challenges:

  1. Remote Initiation of CGM in Older Adults Using Insulin. This study identified several CGM challenges including difficulties with the mobile application, annoyance with frequent alarms, and concerns about Medicare coverage (Abstract 1004-P).
  2. Remote CGM Following Hospital Discharge. Folk S, Sobol T, Gatti T, et al. investigated the feasibility and efficacy of remote CGM compared to manual CGM following hospital discharge. Their study found that barriers to use in the manual CGM group included issues such as incompatible cell phones or the lack of a smartphone.
  3. CGM Use in People Not Living with Diabetes (PNLD) A study led by researchers at University College London (UCL) and Birmingham Children’s Hospital highlighted a lack of evidence for the effective use of CGMs in people not living with diabetes. The researchers concluded that there is currently insufficient published evidence on the accuracy of CGMs in measuring blood glucose levels in PNLD.
  4. Periods of nonadherence A study published by the National Library of Medicine concluded that "there were 183 periods of nonadherence for greater than 1 full day across 36 of the 38 participants, ranging from 1 to 16 per person. Only 2 of the 38 participants completed the 6-month study without a single full day break, while 47.4% of all participants had at least 1 non adherent period of at least 7 consecutive days."
  5. Patient Dissatisfaction and Discontinued Use - A study published in Clinical Diabetes, found that while CGM devices may lead to improved glycemic control, there were many issues with the technology which often led to patient dissatisfaction and discontinued use. Among the top reasons cited was varying levels of accuracy between sensors, particularly on the first and last day of wear. This led to 59% of participants stopping use of their CGM device for at least one month.

In Summary

The continuous glucose monitoring market faces several challenges that need to be addressed. Bluetooth disconnection issues, high costs, accuracy concerns, and the need for better user education are all critical areas that can lead to patient dissatisfaction.

Although the technology will probably continue to evolve, these challenges cause uncertainty among patients. It's crucial for users and healthcare providers to be aware of these issues and consider the options, including the use of a monitor that requires a fingerstick, to ensure effective diabetes management.

Contact us today to learn more about the benefits of cellular remote patient monitoring devices for diabetes and other chronic illnesses.