Continuous glucose monitoring

Stewart B. Harris; Basel Bari; Jeremy Gilbert

doi:10.1503/cmaj.230572

Continuous glucose monitoring (CGM) in diabetes improves outcomes and enhances patient self-management

Compared with traditional fingerstick testing, CGM improves glycemic control and quality of life, and is now recommended for people with type 1 and type 2 diabetes using basal–bolus insulin. 1 Use of CGM improves glycemic outcomes among people with type 2 diabetes treated with basal insulin alone in the primary care setting.2 It alerts users to hypo-or hyperglycemia, and promotes healthy behaviours by providing immediate data on lifestyle choices like diet and exercise.3

Continuous glucose monitoring overcomes the limitations of glycated hemoglobin (HbA_1c)

Unlike HbA_1c, CGM can guide immediate decisions on blood glucose management and provides important metrics, including time in range (Appendix 1, available at www.cmaj.ca/lookup/doi/10.1503/cmaj.230572/tab-related-content).1 A low proportion of time spent in the patient’s target range for blood glucose is associated with an increased risk of microvascular and macrovascular diabetic complications.4

There are 2 types of CGM systems — real-time and intermittently scanned

Real-time CGM automatically collects and displays glucose data, while intermittently scanned CGM requires manual scanning at least every 8 hours. Real-time CGM has a predictive alert that warns of impending hypoglycemia, an important feature for patients with frequent hypoglycemia or hypoglycemia unawareness.1 Choosing between systems should be based on patient needs and preferences.

Interpretation of CGM results is straightforward

Reports can be easily accessed by smartphone, receiver or CGM-specific software (Appendix 1). These provide easy-to-read glycemic data to identify patterns that can enable effective therapeutic adjustments and reduce clinical inertia.5 Continuous glucose monitoring can be successfully implemented in primary care, and numerous resources are available to support this.2

Potential challenges should be considered

Challenges may include body image concerns, sensor adhesion issues, skin irritation and alert fatigue. Cost may be a barrier ($200–$300/mo), but public and private CGM coverage is expanding, and many patients with type 1 and type 2 diabetes using basal–bolus insulin are now covered.

Footnotes

Competing interests: Stewart B. Harris reports research support from AstraZeneca, Eli Lilly, Novo Nordisk and Sanofi. He has also received honoraria or consulting fees from and has participated on advisory boards for Abbott, AstraZeneca, Bayer, Dexcom, Eli Lilly, HLS Therapeutics, Janssen, Novo Nordisk and Sanofi. He has participated in clinical trials for Abbott, Applied Therapeutics, Boehringer Ingelheim, Novartis, Novo Nordisk and Sanofi. Basel Bari has been a member of advisory boards for Novo Nordisk, Sanofi, Boehringer Ingelheim, Astra-Zeneca and Eli Lilly. He has also received grants and honoraria from Master Clinician Alliance, CCRN, Dexcom, Merck, Novo Nordisk, Sanofi, Boehringer Ingelheim, AstraZeneca, Eli Lilly, CPD Network and BD. Jeremy Gilbert reports consulting fees and honoraria from Abbott, Astra Zeneca, Amgen, Boehringer Ingelheim, Dexcom, Eli Lilly, Janssen, Sanofi, Novo Nordisk and HLS Therapeutics, and honoraria from Roche and Master Clinician Alliance. No other competing interests were declared.
This article has been peer reviewed.

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY-NC-ND 4.0) licence, which permits use, distribution and reproduction in any medium, provided that the original publication is properly cited, the use is noncommercial (i.e., research or educational use), and no modifications or adaptations are made. See: https://creativecommons.org/licenses/by-nc-nd/4.0/

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