| [Background]Along with the incidence of diabetes increased steadily, patients with diabetes expands gradually, the diabetes has now become one of the main enemy of the human health, together with cardiovascular diseases, cancer. Prevention of diabetes and its complications has caused severe economic burden and social pressure. In recent years, the prevalence of type 2 diabetes (T2DM) has a dramatically increased trend in China, the latest survey results of Chinese Diabetes Association showed that the prevalence of T2DM in urban adults has been 9.7%, thus the number of T2DM has reached 92.4 million. The latest data of the Diabetes annual meeting of Guangdong Province announced in 2009 show that incidence of diabetes in the Guangdong region is as high as 10%. At the same time, the prevalence of pre-diabetes came up to 15% and impaired glucose tolerance (IGT) changed into diabetes in a certain percentage each year. Patients with T2DM mostly had non-specific symptoms in its early stage, so it often been ignored, an average of 9 to 12 years of preclinical before clinical diagnosis, then a lot of patients would be omission diagnosed. A long-term observation study data show that about 70% of the IFG and IGT patientswill progress to diabetes finally, and this phenomenon is especially prevalent at high risk of diabetes. These are indications that person at high risk of diabetes is of great significance in early diagnosis of diabetes.Therefore, the high risk of diabetes were selected as the objective population of the study.For decades, the diagnosis of diabetes has been based on the blood sugar standards, including fasting plasma glucose (FPG), random blood glucose (RPG) and 75g oral glucose tolerance test (OGTT). However, in clinical research and practice, people gradually realized that this approach has some limitations, such as blood glucose reflects real-time glucose metabolism, which susceptible to interference for a variety of factors, FPG and the OGTT diagnosed diabetes, both the coincidence is not high. The complexity process, highly cost and large variability, poor reproducibility, all of those in practices would be restricted,which not been effective implemented. We may need to seek a more simple, accurate and scientific diagnosis indicators of diabetes. Compared with the single blood glucose testing, HbA1c with a deal of characteristics of high sensitivity, specificity, and stability. HbA1c can organic combined the diagnose and evaluate of the condition for blood glucose and the follow-up of patient's condition,which also reflecting a state of long-term high blood sugar for diabetics. HbA1c provide a more accurate information of the existence and severity of diseases. So the United States with type 1 diabetes Control and Complications trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) diabetes control were conside HbAlc as one of the important evaluation, and fully affirmed the important role of HbAlc in the prevention of the development of complications.The ultimate goal of diagnosis and treatment of diabetes is to control the high blood sugar and the risk of complications. Macrovascular disease affected by many factors, and the specificity with blood sugar is not strong. However, the microvasculardiseases impacted by long-term hyperglycemia, and has relatively close relationship with blood glucose, and those can also diagnosed easily in clinical. The diagnosis boundary value of FPG, OGTT, and 2h PG are based on the association between the blood glucose and diabetic retinopathy (DR), a number of studies have consistently demonstrated that there is also a strong correlation between the diabetic retinopathy and the levels of HbA1c. Whether HbAlc can used for the diagnosis of diabetes will become a hotspot in recent years.The new guidelines of ADA in 2010 formal approval HbAlc as a diagnostic method for diabetes mellitus in first time, and its diagnostic cutoff is≥6.5%. As the cutoff value of blood glucose, the diagnostic value of HbA1c is determined by the inflection point of significantly higher prevalence of retinopathy in epidemiological studies. Although the use of HbA1c to replace FPG or OGTT is a trend, but there are still many questions to be answered. For example, the individual levels of HbA1c affected by many factors, such as hemoglobin, red blood cell metabolism and the racial differences. China is a vast, which both has plain and low altitude, even high altitudes.hemoglobin levels in different regions vary widely among different people. Whether the new indicator is suitable for China's national conditions still to properly assess and accumulated more evidence-based medical informations.[Objective]1. To explore the relationship between the level of HbA1c and the microvascular complications in high-risk population for diabetes of Guangzhou community, and to find the boundary points of HbAlc to diagnosis the microvascular complications2. To compare the diagnostic accuracy of fasting plasma glucose,2h glucose and HbA1c in the diagnostic threshold of microvascular complications in high-risk population for diabetes of Guangzhou community. [Methods]650 cases was randomly chose from 5000 inhabitants of Haizhu District, in Guangzhou using SPSS13.0, all of those aged more than 45 years and had no diabetes before,31 of whom refused to be investigated, therefore the total number was 619 from May 2009 to June 2010. Suffering from various diseases which effect blood glucose (such as cancer, thyroid disease and so on),long-term use oral drugs that affect blood glucose (eg, glucocorticoids, etc.),pregnant women, cardiovascular complications within a month and infectious disease, who have surgery recently, were not selected for this study.First we filled in diabetes risk score and collected medical history, and then conducted body surface measurement. In this study, the Finnish DRS table were used for screening people with high risk factors.The oral glucose tolerance test and glycated hemoglobin, blood lipids were took a week later. People who didn't have the test can not enter follow-up study.After that all the person underwent OGTT were divided into NGT group, IGT group and T2DM group,which according to the 1999 WHO diagnostic criteria on type 2 diabetes.GOD-PAP method was adopted to detect venous glucose, Oxidase method was adopted to detect TG, cholesterol oxidative enzymic method to detect TC, Enzyme-colorimetric method to detect HDL-C and homogeneous enzyme-colorimetric method to detect LDL-C, The instruments are produced by Roche Roche P Module biochemical analyzer Modular P800. HPLC method to detect HbAlc, the instruments are produced by Japan Tosoh Corporation HLC (?)-723GHb G7(inter-batch coefficients of variation were 3.66% and 4.76%). Urinary albumin were measured by immune turbidimetry, The instruments are produced by BN Prospect of German SIEMENS Instruments Corporation.[Results]We have screened 208 patients as high-risk population for diabetes, the detection rate was 33.6%,71 patients with NGT included 31 males and 40 females; 82 patients with IGR included 29 males and 53 females; 55 T2DM with 26 males and 29 females.1. The Basic conditions in the three groupsThe comparison of basic conditions in low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%)groups:there is no significant difference in LDL-C,TG,CHOL, and there is significant difference in FBG,HbA1c,2hPG. Blood pressure, blood glucose, HbA1c, cholesterol and triglycerides of high HbA1c groups is higher than other two groups, and those people also have Waist circumference. As follows:Age:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 0.398, P=0.672);Risk score:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 1.858, P=0.159).Median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group are both higher than low HbA1c(HbA1c<5.7%) group;Waist:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 0.977, P=0.378), high HbA1c (HbA1c>6.5%) group are higher than median HbA1c (5.7%≤HbA1c≤6.4%) and low HbA1c(HbAlc<5.7%);BMI:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 1.210, P=0.300).Median HbA1c (5.7%≤HbA1c≤6.4%) and high HbAlc (HbA1c≥6.5%) group are both higher than low HbA1c(HbA1c<5.7%) group, median HbA1c (5.7%≤HbA1c≤6.4%) are higher than low HbA1c(HbA1c<5.7%) group; Systolic blood pressure:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F=1.133, P=0.875). Median HbAlc (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group are both higher than low HbA1c(HbA1c< 5.7%) group;Diastolic blood pressure:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c(5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 0.226, P=0.798);Pulse pressure:There is no statistic difference between low HbA1c(HbA1c< 5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 0.464, P=0.629);FBG:There is significant difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 19.067, P=0.000). High HbA1c (HbA1c≥6.5%) group are higher than median HbA1c (5.7%≤HbA1c≤6.4%) group, the statistic difference is significant (P=0.002). Median HbA1c (5.7%≤HbA1c≤6.4%) group are higher than low HbA1c(HbA1c<5.7%), the statistic difference is significant (P=0.001):2h-PG:There is significant difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 43.030, P=0.000). High HbA1c (HbA1c≥6.5%) group are higher than median HbAlc (5.7%≤HbA1c≤6.4%) group, the statistic difference is significant (P=0.000). Median HbA1c (5.7%≤HbA1c≤6.4%) group are higher than low HbA1c(HbA1c<5.7%), the statistic difference is significant (P=0.000);HbA1c:There is significant difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 177.810, P=0.000). High HbAlc (HbA1c≥6.5%) group are higher than median HbA1c (5.7%≤HbA1c≤6.4%) group, the statistic difference is significant (P=0.000). Median HbA1c (5.7%≤HbA1c≤6.4%) group are higher than low HbA1c(HbA1c< 5.7%), the statistic difference is significant (P=0.000);CHOL:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 0.158, P=0.854);TG:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F=0.812, P-0.450);HDL-C:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 2.001, P=0.138);LDL-C:There is no statistic difference between low HbA1c(HbA1c<5.7%), median HbA1c (5.7%≤HbA1c≤6.4%) and high HbA1c (HbA1c≥6.5%) group (F= 1.086, P=0.339);2. Correlation Analysis of HbAlc with FPG and 2hPGThe linear correlation analysis of HbA1c with FPG and 2hPG showed that:there were significant positive correlation between HbA1c levels and FPG,2hPG (HbA1c and FPG:the overall correlation coefficient (r) is 0.755 between HbA1c levels and FPG, the correlation coefficient (r) is 0.755 between HbAlc levels and 2hPG, all P <0.000). With the increasing of HbA1c, The linear correlation between HbA1c and FPG and 2hPG show a increasing trend.3. Correlation analysis between the levels of HbA1c, FPG,2hPG and the prevalence of retinopathy and microalbuminuriaThe fig.1 show different levels of HbA1c and the prevalence of retinopathy: prevalence of retinopathy increased with increasing levels of HbA1c, HbA1c and the prevalence of retinopathy were significantly correlated (P<0.01). Compared with the prevalence of retinopathy at 5.2-5.5 levels of HbAlc, the prevalence of retinopathy at 5.6-5.9 levels of HbAlc has tripled. Fig.2 show levels of HbAlc and the different prevalence of microalbuminuria:the prevalence of microalbuminuria increased with the concentration of HbA1c. However, compared with retinopathy, this increasing trend has slowed down. Compared with the prevalence of microalbuminuria at 5.2-5.5 levels of HbA1c, the prevalence of microalbuminuria at 5.6-5.9 levels of HbA1c has increased slightly, levels of HbA1c above 6.6 compared with the 6.4-6.5 group, the prevalence show a small downward trend.4. The optimal cut-point for detecting the microvascular complicationsThe optimal cut-point for detecting the retinopathy of HbA1c, FPG,2hPG was 5.8%,7.0mmol/L,10.9mmol/L.When detecting whether there is microalbuminuria, the cut-point of HbA1c was 5.8%, which is exactly match to its cut-point of retinopathy. The prevalence of microalbuminuria was significantly increased when the cut-point of FPG and 2hPG was 6.4 mmol/L and 10.7 mmol/L.5. Comparison of the diagnostic threshold of FPG,2hPG HbA1c to predict microvascular complicationsComparing of three kinds of diagnostic methods,the lager the area under the curve the more efficient of the method. When retinopathy is the end of the event, the results of the area under the curve were 2hPG (0.783)> HbA1c (0.754)> FPG (0.659), show 2hPG and HbAlc have higher diagnostic accuracy. The area of 2hPG under the curve (0.783) and HbA1c (0.754) show no significant difference, while the two area under the curve were greater than FPG (0.659). The results showed that, the effect of HbA1c, and 2hPG for detecting the retinopathy has no significant difference, compared both of them, the effect of FPG is low. On the other hand, the effect of HbA1c, FPG,2hPG for detecting microalbuminuria is not satisfactory, the results of the area under the curve were HbAlc (0.559)> 2hPG (0.550)> FPG (0.534).It suggest that the effect of HbAlc for detecting microalbuminuria is better than FPG relatively.[Conclusions]1. There is a linear relationship between HbAlc and retinopathy, and microalbuminuria in high-risk groups with diabetes.2. The best value of HbAlc for detecting the prevalence of microvascular complications may be above 5.8% range.3. There is no significant difference of the effect for detecting the prevalence of microvascular complications between HbAlc and 2hPG, while FPG is relatively low. In clinical applications, if the level of HbAlc is greater than 5.8%, other examination methods needed to combined togher to detect the existence of diabetic microvascular complications. |
PDF Full Text Request