What are the adverse effects of Continuous Glucose Monitors (CGM)?

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Last updated: March 4, 2025View editorial policy

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From the Guidelines

Continuous glucose monitors (CGMs) can cause several adverse effects, including skin irritation, pain or discomfort, bruising or bleeding, infection, technical issues, sleep disturbances, and psychological effects, as noted in the most recent guidelines 1. The most common adverse effect is skin irritation at the insertion site, which may include redness, itching, rashes, or allergic reactions to the adhesive used to secure the device. Some users experience pain or discomfort during sensor insertion or while wearing the device, particularly during physical activities. Bruising or bleeding at the insertion site can occur, especially in individuals taking blood thinners. Infection is a rare but possible complication if proper hygiene isn't maintained during insertion. Technical issues like sensor failures, inaccurate readings, or connectivity problems between the sensor and receiver/smartphone can lead to frustration and potentially dangerous situations if glucose levels aren't accurately monitored. Some users report sleep disturbances from alarms or discomfort from wearing the device overnight. Psychological effects may include anxiety from constant glucose monitoring or alarm fatigue from frequent alerts. Key considerations for minimizing these adverse effects include proper education on device use and maintenance, as well as awareness of potential interfering substances that may affect accuracy, as highlighted in recent standards of care 1. Despite these potential adverse effects, CGMs provide valuable continuous glucose data that helps many people with diabetes improve their glycemic control, and most adverse effects can be managed with proper care and technique. It is essential to weigh these potential adverse effects against the benefits of CGM use, which can lead to improved glycemic control and reduced risk of diabetes-related complications, as supported by recent guidelines 1.

From the Research

Adverse Effects of Continuous Glucose Monitors (CGM)

  • There is limited information available on the adverse effects of CGM in the provided studies.
  • However, some studies mention the potential risks associated with CGM, such as:
    • Skin irritation or allergic reactions to the sensor or adhesive 2
    • Infection or bleeding at the sensor insertion site 2
    • Technical issues with the device, such as malfunction or inaccurate readings 2
  • One study notes that CGM can help reduce the risk of hypoglycemia and hyperglycemia, but does not mention any specific adverse effects 3
  • Another study discusses the benefits and limitations of CGM in type 1 diabetes, but does not provide information on adverse effects 4
  • A study on steroid-induced hyperglycemia in patients with dermatologic diseases uses CGM to monitor glucose levels, but does not report any adverse effects related to the device itself 5
  • A review of the effectiveness and cost-effectiveness of CGM combined with self-monitoring of blood glucose mentions that moderate quality evidence suggests CGM + SMBG is not more effective than SMBG alone in reducing HbA1c or hypoglycemic events in type 1 diabetes, but does not discuss adverse effects in detail 2
  • A report on managing patients with insulin pumps and continuous glucose monitors in the hospital setting notes that the use of this technology can improve inpatient glycemic outcomes and reduce hypoglycemia, but does not mention specific adverse effects 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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