Blood glucose monitoring is one of the "five carriages" of diabetes treatment. However, some patients may have some misunderstandings about blood glucose monitoring, leading to wrong practices, resulting in unsatisfactory blood glucose control. For example, some patients only monitor fasting blood sugar and never measure postprandial blood sugar; some patients think blood sugar monitoring is too troublesome and only measure glycated hemoglobin every 3 months. As long as the glycated hemoglobin value is normal, they think their blood sugar control is stable. In fact, if you want to control diabetes well, you must have both blood sugar and glycated hemoglobin!
Blood glucose monitoring - monitoring blood glucose at a point in time
Blood sugar refers to free glucose that exists in the blood. The concentration of human blood sugar will be affected by eating, exercise, emotions, etc., so human blood sugar is in a state of fluctuation. The blood sugar value determines the blood sugar level at a point in time. Generally, Diabetic patients need to measure fasting blood glucose and 2-hour postprandial blood glucose to evaluate their blood sugar control.
Glycated hemoglobin – monitors long-term blood sugar control
Hemoglobin is the carrier of oxygen in red blood cells and an important component of human blood. Glucose in the blood can enter red blood cells and combine with the hemoglobin in them to form a combination, which is what we call glycated hemoglobin. The combination of glucose and hemoglobin is relatively slow. This process is called glycosylation. Once they are combined, they are irreversible.
The amount of glycated hemoglobin is related to the glucose concentration in the blood. When the blood glucose concentration continues to be at a high level, the amount of glycated hemoglobin also increases. Therefore, the overall blood sugar control status of diabetic patients can be evaluated by measuring the glycated hemoglobin in the blood.
However, glycated hemoglobin can only reflect long-term blood sugar control. Since the lifespan of red blood cells in the human body is generally 120 days, the glycated hemoglobin level reflects the average blood sugar level in the 2 to 3 months before the test. The level of glycated hemoglobin has nothing to do with factors such as the time of blood draw, whether the patient is fasting, whether the patient uses insulin, etc. It is a good indicator for judging the long-term blood sugar control of diabetic patients.
The significance of fasting blood glucose monitoring
Reflects basal insulin secretion
In fact, fasting blood glucose can indirectly reflect the body's own basal insulin secretion level in the absence of stress factors, that is, it reflects the body's basal insulin secretion. Some patients with a long course of disease are prone to insufficient basal insulin secretion.
reaction dawn phenomenon
Since the secretion of glycemic hormones in the human body, such as growth hormone and epinephrine, begins to increase regularly in the early morning, the body is preparing for a new day of work and life. Due to the reduced sugar regulation ability of diabetic patients, blood sugar rises in the morning. high.
Dawn phenomenon refers to the situation in which diabetic patients have high blood sugar or increased insulin demand at dawn (3 to 9 o'clock) when their blood sugar control is acceptable at night and there is no hypoglycemia. Hyperglycemia is defined as the fasting blood sugar value. At least 1.11 mmol/L above the nocturnal nadir or a 20% increase in fasting insulin requirement from the nocturnal nadir. (Data source: "Chinese Journal of Endocrinology and Metabolism")
Medication regimen evaluation
Fasting blood glucose can also reflect the efficacy of antidiabetic drugs. For patients who have long-term use of antidiabetic drugs, good control of fasting blood glucose is of great significance. If the antidiabetic plan is unreasonable, fasting blood glucose may not be well controlled.
Reflects the status of the previous day’s dinner. Fasting blood sugar is also affected by the previous day’s dinner. If the patient's usually measured fasting blood sugar is within a certain range, but one time the fasting blood sugar value is higher, then the first thing you need to consider is what food was eaten the night before and whether the energy intake of these foods exceeded the standard.
The significance of blood glucose monitoring 2 hours after a meal
Prevent diabetes complications
Postprandial hyperglycemia is an independent risk factor for macrovascular disease. If postprandial blood sugar can be controlled well, cardiovascular events can be effectively prevented. Studies have shown that for every 1 mmol/L increase in blood sugar 2 hours after a meal, the threat of death is equivalent to a 7 mmHg increase in systolic blood pressure in patients with hypertension.
Similarly, postprandial blood sugar is also related to the occurrence of diabetic microvascular complications. Studies have found that postprandial hyperglycemia will increase the risk of retinopathy in diabetic patients and will also accelerate the development of retinopathy. Therefore, diabetic patients should strengthen post-meal blood sugar monitoring to prevent diabetic complications.
So what range should diabetics control their blood sugar? Controlling blood sugar within 10 mmol/L 2 hours after a meal is acceptable for elderly diabetic patients or patients with serious complications. However, for patients under middle age and those who are not seriously ill, mild hyperglycemia has a negative impact on blood pressure, Adverse cardiovascular effects. Therefore, it is necessary to control postprandial blood sugar below 7.8 mmol/L as much as possible, which will also help reduce the burden on pancreatic β cells and protect the function of pancreatic β cells.
Postprandial hyperglycemia and fasting blood glucose were found to be normal
Many people only check fasting blood sugar during physical examination. If fasting blood sugar is normal, they think they do not have diabetes. In fact, there are three situations of high blood sugar in diabetic patients. The first is high fasting blood sugar but normal postprandial blood sugar; the second is normal fasting blood sugar but high postprandial blood sugar; the third is fasting blood sugar and postprandial blood sugar. All high. If the physical examination only checks fasting blood sugar, then postprandial hyperglycemia will be missed in the second and third cases. Therefore, when everyone checks blood sugar during daily physical examination, they must check both fasting blood sugar and 2-hour postprandial blood sugar.
Reflect whether eating and hypoglycemic drugs are appropriate
Blood sugar 2 hours after a meal can reflect the patient's blood sugar control after eating and taking medication. If you eat high-carbohydrate foods, your blood sugar will be high 2 hours after a meal. If the dose of oral medication is insufficient, your blood sugar will also be high 2 hours after a meal. Therefore, diabetic patients can adjust their eating and medication according to their blood sugar status 2 hours after a meal.
The significance of glycosylated hemoglobin monitoring
Reflect long-term blood sugar control status
As mentioned above, glycated hemoglobin reflects the average blood sugar status in the 120 days before the test, and reflects the long-term blood sugar control status.
Predict risk of diabetes complications
Patients with poor blood sugar control are prone to complications. Since glycated hemoglobin reflects average blood sugar, there is an intuitive connection between glycated hemoglobin and complications.
Comparison table of relationship between glycosylated hemoglobin (HbA1c) and average blood sugar
HbA1c (%) mean plasma glucose level [mmlo/L (mg/dl)]
6 7.0(126)
7 8.6(154)
8 10.2(183)
9 11.8(212)
10 13.4(240)
11 14.9(269)
12 16.5(298)
The normal value of glycated hemoglobin is 4% to 6%. The reasonable glycated hemoglobin control target is less than 7.0%. The glycated hemoglobin value greater than 9% (corresponding to an average blood sugar of 10.2 mmol/L) is poor control and is the occurrence of chronic complications. , risk factors for the development of diabetes, and acute complications such as ketoacidosis may occur. At this time, blood sugar management needs to be strengthened. (Data source: "China Type 2 Diabetes Prevention and Treatment Guidelines (2017 Edition)")
