Blood glucose monitoring is an important part of the “five horsemen” of diabetes management. With the development of glucose monitoring technology, more and more evidence confirms the irreplaceable role of glucose testing in the effective management of diabetes. The development of blood glucose monitoring technology has gone through a long process, from the initial urine glucose test, glycated hemoglobin (HbA1c), blood glucose meter, glycated serum albumin, until the end of last century, a new technology that is more conducive to a comprehensive understanding of blood glucose changes – continuous glucose monitoring (CGM). If these glucose monitoring techniques can be combined organically, it will help clinicians to understand the whole picture of patients’ blood glucose more perfectly. The traditional blood glucose monitoring methods have different limitations: 1. Self-monitoring is the basic form of blood glucose monitoring, but point glucose reflects the instantaneous blood glucose changes and cannot completely reflect the whole day blood glucose value of patients, and there is a monitoring “blind spot”; 2. CGM is an effective supplement to traditional blood glucose monitoring methods and has been gradually promoted and applied in clinical practice. changes and information about the influence of its related factors. CGM system is composed of five parts: sensing probe, glucose recorder, needle injector, information extractor and software. The glucose sensing probe is a small, sterile, flexible probe that senses glucose levels in tissue fluids after entering the subcutaneous area. CGMs are divided into two categories: retrospective and real-time CGMs. The latter is often used in combination with an insulin pump, i.e., a sensor-enhanced insulin pump. If the traditional blood glucose monitoring method is compared to a “camera”, CGM can be called a “video recorder”, which can provide a comprehensive blood glucose log, including 288 blood glucose values per day, daily blood glucose graph, multi-day blood glucose graph, time-specific blood glucose graph CGM can provide a comprehensive blood glucose log, including 288 blood glucose values per day, daily blood glucose graph, multi-day blood glucose graph, time-specific blood glucose graph, and blood glucose graph summary containing blood glucose fluctuation, average value, average absolute difference, correlation coefficient, pie chart and area under blood glucose curve. The graphs of blood glucose changes provided by CGM can identify various problems at a glance, such as nocturnal hypoglycemia, and help identify “hidden” hypoglycemia and hyperglycemia. CGM entered China in 2002 and was first applied in Shanghai Sixth Hospital, and gradually spread to the whole country. China has also accumulated a lot of clinical application experience and research data of CGM. Professor Jia Weiping talked about the research evidence of CGM in China in recent years from the following three aspects: Characteristics of blood glucose fluctuation in Chinese population Applying CGM to evaluate the characteristics of blood glucose fluctuation in people with normal glucose regulation, impaired glucose regulation and newly diagnosed type 2 diabetes, the results showed that normal people showed fluctuating changes in blood glucose, but the fluctuations were small; the average blood glucose level of people with impaired glucose regulation was about 15% higher than that of normal people, but The average blood glucose level of those with impaired glucose regulation was about 15% higher than normal, but their intra-day blood glucose fluctuations had increased significantly, up to 50% higher than normal; type 2 diabetic patients showed significantly higher intra-day and inter-day blood glucose fluctuations in addition to the overall increase in blood glucose level. These results suggest that abnormal blood glucose fluctuation is one of the important features of glucose metabolism disorder. In 2009, the National Collaborative Group on Ambulatory Glucose established the normal reference values of ambulatory glucose in China through the ambulatory glucose profiles of a total of 434 normal individuals in 10 hospitals for 3 consecutive days (see the table below). A multicenter study on the evaluation of CGM accuracy published by Prof. Jia Weiping’s team in 2012 also confirmed that CGM has high clinical application value and safety. Its results showed that nearly 90% of the deviations between the probe and venous blood glucose were within 20%, and CGM has better accuracy both in immediate blood glucose and in reflecting the trend of blood glucose changes. Relationship between blood glucose fluctuation and metabolic diseases Using CGM, we can find that many metabolic diseases show changes in blood glucose fluctuation at the early stage of development. For example, studies have shown that patients with polycystic ovary syndrome (POCS) with normal glucose tolerance have shown changes in the pattern of postprandial glucose fluctuations, and CGM can detect this change more comprehensively and sensitively. CGM can also detect that mildly elevated levels of liver enzyme ALT in metabolically normal individuals first affect nighttime glucose, which may be related to hepatic insulin resistance. Preliminary analysis of blood glucose fluctuations and microalbuminuria showed that more than half of type 2 diabetic patients with relatively well-controlled HbA1c can exhibit abnormal blood glucose fluctuations and lead to an increased risk of developing microalbuminuria, indicating that blood glucose fluctuations are one of the risk factors for developing microalbuminuria in type 2 diabetic patients. In terms of macrovascular lesions, carotid intima-media thickness (C-IMT) was positively correlated with glucose fluctuations in patients with MRA without carotid plaque, suggesting that the level of glucose fluctuations in type 2 diabetic patients is closely related to subclinical atherosclerosis. CGM assessment of treatment effect The study on the effect of insulin therapy on blood glucose fluctuation found that the level of blood glucose fluctuation in normal glucose-regulated individuals was negatively correlated with the early phase insulin secretion function, indicating that those with high blood glucose fluctuation have relatively poor islet function, while intensive treatment of type 2 diabetes with insulin can reduce blood glucose fluctuation by 30% to 40%. Several studies on the effect of oral hypoglycemic agents on blood glucose fluctuations have confirmed that although common oral agents such as glipizide, nateglinide and acarbose can also significantly reduce blood glucose fluctuations in the monotherapy of type 2 diabetes, the improvement of blood glucose fluctuations by combined treatment is more significant. In addition, CGM can assist in the preoperative diagnosis and postoperative efficacy assessment of insulinoma by calculating the percentage of time occupied by preoperative glucose ≤2.8 mmol/L and postoperative glucose reaching 3.5~7.7 mmol/L.