Navigating the Seas of Glycemic Control: The Role of Continuous Glucose Monitoring in Type 1 Diabetes Mellitus

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Diabetes Metab J. 2023;47(3):345-346
Publication date (electronic) : 2023 May 26
doi :
Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
Corresponding author: Jun Sung Moon Division of Endocrinology and Metabolism, Department of Internal Medicine, Yeungnam University College of Medicine, 170 Hyeonchung-ro, Nam-gu, Daegu 42415, Korea E-mail:

Achieving appropriate glycemic control in type 1 diabetes mellitus (T1DM) can be likened to sailing a ship on rough and unpredictable seas. Just as a ship’s captain must be vigilant to navigate through ever-changing weather conditions and unexpected obstacles, managing blood glucose levels in T1DM requires constant monitoring and adjustments, and careful decision-making. Sometimes a ship can be tossed about by turbulent waves, glucose levels in T1DM can be affected by factors such as stress, illness, and physical activity. But just as a captain can successfully reach destination with proper navigation skills and a well-equipped ship, people with T1DM can achieve their blood glucose goals and avoid the complications associated with hyper- and hypoglycemia.

Appropriate blood glucose monitoring (BGM) is the cornerstone of managing diabetes, especially for people with T1DM who need to use multiple insulin injections or insulin pumps, including automated insulin delivery systems. Continuous glucose monitoring (CGM) technology has progressively improved in terms of convenience and accuracy during the past decade, changing the paradigm of glycemic management by surpassing the limitations of average values and attempts to maintain optimal control within a range [1]. Previous clinical trials have shown that CGM systems have clinical benefits for patients who require intensive insulin therapy (especially those with T1DM), compared with traditional BGM [1]. Therefore, real-time CGM (RT-CGM) or intermittent CGM (isCGM) is highly recommended for patients with diabetes who need multiple injections or continuous subcutaneous insulin infusions [2,3].

In this issue of the Diabetes & Metabolism Journal, Lee et al. [4] report on a study that examined the effects of CGM on glycemic control in patients with T1DM. Their findings, based on real-world data from a single center, show that CGM use was associated with better glycemic control than BGM. After adjusting for several confounding variables, they found that CGM use was inversely associated with glycosylated hemoglobin (HbA1c) levels, and patients who used CGM had 1.9 times higher odds of achieving an HbA1c <7% in a real-world clinical setting. They were unable to analyze CGM metrics in non-users, but they did show that CGM users had a mean time-inrange (TIR) value that approached the goal of TIR >70%, which recent guidelines have recommended. Specifically, the study reports median TIR values of 64.20% (interquartile range [IQR], 51.73 to 72.43) and 62.80% (IQR, 55.00 to 71.90) after 30 and 90 days of use, respectively. Those results strengthen the evidence for the glucose-lowering efficacy of CGM in patients with T1DM [1]. CGM has the potential to offer patients not only monitoring data, but also educational information about their glucose response to specific meals and exercise. In addition, proper use of CGM can motivate patients to control their blood glucose and determine the right time and dose for insulin injections, improving glucose excursions and reducing fluctuations.

The effectiveness of CGM can vary depending on the need and number of scans. Most participants (87.4%) in the study reported here used RT-CGM, and the reported benefits of CGM use derived mainly from RT-CGM rather than isCGM (Supplementary Table 2). RT-CGM has several advantages over isCGM, including minimizing the risk of data loss and providing alerts that allow patients to take preventive action in the event of hypoglycemia or impending hypoglycemia. The ALERTT1 study was a multi-center, randomized controlled trial that compared the effectiveness of RT-CGM and 1st generation isCGM in managing T1DM. It showed that switching from isCGM without alerts to RT-CGM with alerts improved glycemic metrics (HbA1c levels, TIR, and time below range) after 6 months [5]. An extension of the trial assessed the effects of switching from isCGM to RT-CGM for up to 24 months and found that TIR continued to increase, and HbA1c levels decreased throughout the extended period. The study concluded that the use of RT-CGM with alerts is beneficial and improves the care of adults with T1DM [6].

Advances in technology, such as the artificial pancreas, are promising to further improve the treatment of T1DM in the future. The artificial pancreas system is an automated closed-loop system that can monitor glucose levels and deliver insulin accordingly. This technology will help individuals with T1DM manage their blood sugar levels more effectively and reduce the risk of complications. However, it is important to note that technology alone is not enough. Fundamental motivation and structured education are still critical components in successfully managing T1DM. Patients need to understand the importance of healthy eating habits, regular exercise, and medication adherence, among other things. When technological advances and structured education are properly integrated, individuals with T1DM can have improved outcomes and better quality of life.



No potential conflict of interest relevant to this article was reported.


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