What is the significance of glycated hemoglobin measurement

There are more and more diabetes patients nowadays, which is inseparable from unhealthy lifestyles and habits. In recent years, the incidence of hyperglycemia has tended to be younger and younger, and the detection of glycosylated hemoglobin has received increasing attention. Therefore, it is recommended that you test your blood sugar after the age of 35, which will help prevent and treat diabetes earlier.

The purpose of the measurement is to eliminate the impact of fluctuating blood sugar on the control and observation of the disease. Therefore, for patients with type 1 diabetes who have large blood sugar fluctuations, measuring glycosylated hemoglobin is a valuable indicator of blood sugar control. For patients with type 2 diabetes, blood sugar and urine sugar measurements are simpler and more economical, and can more reliably reflect the control of the disease. Therefore, the significance of measuring glycosylated hemoglobin is lower than that for patients with type 1 diabetes. However, it can be used as an auxiliary examination to determine whether oral medications are ineffective and require insulin treatment. The normal value of glycosylated hemoglobin is 4% to 6%. <6% is under controlled and hypoglycemia may occur easily; 6% to 7% is relatively ideal; 7% to 8% is average blood sugar control; 8% to 9% is not ideal control and it is necessary to strengthen blood sugar control, pay more attention to diet structure and exercise, and adjust the treatment plan under the guidance of a doctor; >9% is very poor blood sugar control, which is a risk factor for the development of chronic complications, and may cause complications such as diabetic nephropathy and arteriosclerosis, and may also cause acute complications such as ketoacidosis, so when it is >8%, blood sugar control should be strengthened.

Helps to understand chronic complications of diabetes: Blood glucose measurement only represents the immediate blood glucose level, indicating the patient's physical condition at the time, and cannot be used as an indicator to evaluate the degree of disease control. If the glycated hemoglobin measurement is >9%, it means that the patient has persistent hyperglycemia, which may lead to complications such as diabetic nephropathy, arteriosclerosis, and cataracts. It is also a high-risk factor for death from myocardial infarction and stroke. Chen Xiaozhuan et al. [1] reported that increased levels of glycosylated hemoglobin are associated with the occurrence, development, and prognosis of ischemic cerebral infarction.

Used for auxiliary diagnosis of diabetes: the glycosylated hemoglobin level in healthy people is 4% to 6%, while that in patients with uncontrolled diabetes can be as high as 10% to 20%; if the glycosylated hemoglobin level is randomly tested and is <8%, diabetes is generally not considered. When glycosylated hemoglobin is >9%, the accuracy of predicting diabetes is about 78%, the sensitivity is 68%, and the specificity is 94%. When glycosylated hemoglobin is >10%, more than 80% of people have diabetes, the sensitivity is 43%, the specificity is 99%, and the effectiveness is 86%. Therefore, it is not recommended to use glycosylated hemoglobin alone to diagnose diabetes because its accuracy is not high and sometimes causes difficulties in clinical interpretation.

The significance of testing in gestational diabetes mellitus (GDM): It is not enough to measure blood sugar alone in gestational diabetes mellitus. Glycated hemoglobin should be controlled to <8% to avoid macrosomia, stillbirth, teratoma, and preeclampsia. Therefore, glycosylated hemoglobin is an important parameter for the control of gestational diabetes. Agarwar et al. found in a diabetes screening experiment for pregnant women that the sensitivity of glycosylated hemoglobin at 5% was 921%, and the negative predictive value was 869%.