空腹血糖联合糖化血红蛋白检测对糖尿病筛查的临床意义

目的评价联合应用空腹血糖和糖化血红蛋白(HbA1c)检测对糖尿病筛查的临床价值。方法对8669名特定人群,同时进行空腹血糖和糖化血红蛋白(HbA1c)检测,所得数据进行对比分析。结果单独以空腹血糖大于等于6.1mmol/L筛查出的糖尿病风险人群为743人,占总检测人数的8.6%;单独以糖化血红蛋白(HbA1c)大于等于6%筛查出的糖尿病风险人群为627人,占总检测人数的7.2%;联合两种检测进行筛查,以两个指标中任何一个超过切点的都筛出来,可筛查出943人,风险筛出率为10.9%;通过统计学分析,差异有统计学意义(P﹤0.01)。结论空腹血糖或糖化血红蛋白(HbA1c)单个指标进行糖尿病风险筛查,都会有一部分可疑人群无法筛出,二者联合应用,可以筛查出更多处于糖尿病风险的可疑人群。     

Combined use of fasting plasma glucose and HbA1c predicts the progression to diabetes in Chinese subjects

OBJECTIVE: We have previously suggested using the paired values of fasting plasma glucose (FPG) and HbA1c to identify potential diabetic subjects. In this article, we followed up on 208 nondiabetic subjects and examined their rates of progression to diabetes. We analyzed their likelihood of becoming diabetic according to their baseline FPG and HbA1c concentrations. RESEARCH DESIGN AND METHODS: Between 1988 and 1995, 2,877 Chinese subjects with risk factors for diabetes underwent screening. Of these, 2,250 had FPG <7.8 mmol/l and 2-h plasma glucose (PG) <11.1 mmol/l. Of these 2,250 subjects, 265 were randomly recruited for an annual oral glucose tolerance test (OGTT) until they progressed to develop diabetes. Of those 265 subjects, 57 had baseline FPG > or =7.0 mmol/l and were excluded from the present analysis. Hence, the progression of glucose tolerance in 208 subjects who were nondiabetic according to the new American Diabetes Association diagnostic criteria (FPG < 7.0 mmol/l and 2-h PG < 11.1 mmol/l) was examined RESULTS: Of the 208 nondiabetic subjects, 26 (12.5%) were men and 182 (87.5%) were women. After a mean follow-up of 1.60 +/- 1.16 years (range 1-7, median 1), 44 (21.2%) progressed to develop diabetes and 164 (78.8%) remained nondiabetic. Those who were diabetic at the end of the study had a high likelihood ratio (LR) of 9.3 to have baseline FPG > or =6.1 mmol/l and baseline HbA1c > or =6.1%. This was compared with a low LR of 0.6-1.1 in diabetic subjects who had either FPG <6.1 mmol/l or HbA1c <6.1% or both at baseline. The crude rate of progression to diabetes was more than five times higher (44.1 vs. 8.1%) in those whose baseline FPG was > or =6.1 mmol/l and baseline HbA1c was > or =6.1% compared with those whose baseline FPG was <6.1 mmol/l and baseline HbA1c was <6.1%. CONCLUSIONS: For Chinese subjects with risk factors for glucose intolerance, the use of paired FPG and HbA1c values helped to identify potential diabetic subjects. Those with an FPG > or =6.1 mmol/l and HbA1c > or =6.1% had a rate of progression to diabetes more than five times higher than those with an FPG <6.1 mmol/l and an HbA1c <6.1% after a mean follow-up of 1.6 years. Those with an FPG > or =6.1 but <7.0 mmol/l, especially if their HbA1c was > or =6.1%, should undergo an OGTT to confirm diabetes. Subjects with an FPG <6.1 mmol/l and/or an HbA1c <6.1% should have regular screening using the paired values of FPG and HbA1c.     

Receiver operating characteristic analysis on fasting plasma glucose, HbA1c, and fructosamine on diabetes screening.

OBJECTIVE: To determine the efficacy of HbA1c and fructosamine as alternatives to fasting plasma glucose (FPG) for diabetes screening. RESEARCH DESIGN AND METHODS: Receiver operating characteristic (ROC) analysis was conducted on the above tests. Comparison among tests was based on the area under ROC curve of a test. World Health Organization criteria for classifying glucose tolerance status of the subjects was used. The study consisted of subjects (n = 583) who visited the clinic from September to October 1989 and all diabetic cases (n = 36) from November 1989 to March 1990, after excluding those less than 40 yr of age or with hypoglycemic therapies (469 were normal, 88 with impaired glucose tolerance ( IGT], and 62 with diabetes). RESULTS: Area under ROC curve of HbA1c was not different from that of FPG. Area under curve of fructosamine was significantly smaller than that of FPG. For all tests, overall efficacy of a test to detect IGT and diabetes was considerably diminished compared with detection of diabetes alone. CONCLUSIONS: The discriminating ability of HbA1c is almost the same as that of FPG, therefore HbA1c is a good alternative to FPG. Fructosamine is not suitable for diabetes screening.     

Variability in the relationship between mean plasma glucose and HbA1c: implications for the assessment of glycemic control

BACKGROUND: Previous studies have shown a single linear relationship between mean plasma glucose (MPG) and hemoglobin A(1c) (HbA(1c)). We examined the relationship in different treatment groups of patients with type 1 diabetes participating in the Diabetes Control and Complications Trial (DCCT). METHODS: Seven-point glucose profiles (premeal, postmeal, and bedtime) and HbA(1c) were measured quarterly during the DCCT. We studied measurements from (a) intensively treated patients at study commencement, (b) intensively treated patients after stabilization of their glycemia (from 6 months onward), and (c) conventionally treated patients from 6 months onward. Only complete glucose profile and HbA(1c) pairings were considered (n = 589, 11 483, and 11 855, respectively). RESULTS: From 6 months into the trial, conventionally treated patients had consistently higher MPG concentrations than intensively treated patients at any given HbA(1c) value (mean difference, 1.6 mmol/L at 7% HbA(1c), increasing to 2.8 mmol/L at 11% HbA(1c)). Similarly, at the same HbA(1c), the MPG of intensively treated patients at baseline was higher than in the same individuals after 6 months of intensive treatment (1.2 mmol/L difference at 7% HbA(1c), increasing to 4.6 mmol/L at 11% HbA(1c)). CONCLUSIONS: The relationship between MPG and HbA(1c) is not constant but differs depending on the glycemic control of the population being studied. Having lower mean glucose at the same HbA(1c) may help explain why intensive DCCT treatment appeared intrinsically linked to both increased hypoglycemia and decreased microvascular complications compared with conventional treatment. These findings may also have implications for expressing HbA(1c) as mean blood glucose equivalent.     

空腹血糖及糖化血红蛋白用于筛查糖耐量减退的比较性研究

目的比较空腹血糖（FPG）和糖化血红蛋白（HbAlc）在筛查糖耐量减退（IGT）中的应用价值。方法到我院门诊为明确有无血糖异常而就诊者336人，测定空腹血糖、糖化血红蛋白，并行口服葡萄糖耐量试验（OGTT）。结果按照1999年WHO的DM诊断标准，本研究人群空腹血糖〈6．1者124例，≥6．1-〈7．0者56例，≥7．0者156例；糖化血红蛋白〈6．1者84例，≥6．1者252例；OGTT2 hPG〈7．8者92例，≥7．8-〈11．1者99例，≥11．1者145例。结论糖化血红蛋白和空腹血糖均不适用于筛查IGT人群，但糖化血红蛋白比空腹血糖提示病人是否存在血糖异常更敏感。     

Admission glucose,fasting glucose,HbA1c levels and the SYNTAX score in non-diabetic patients undergoing coronary angiography

Background

Pre-diabetic state is a major risk factor for the development of diabetes and cardiovascular events. Admission glucose, fasting glucose and HbA1c levels have an effect on prognosis in patients with pre-diabetes and in non-diabetic individuals. The aim of the present study was to investigate which of the following glucometabolic markers (admission glucose, fasting glucose and HbA1c levels) is correlated with the severity of coronary artery disease (CAD) in non-diabetic patients.

Methods

CAD severity according to SYNTAX score was prospectively evaluated in 226 non-diabetic patients hospitalized with myocardial infarction or stable angina and underwent coronary angiography. Glucose intolerance was assessed by serum admission glucose, fasting glucose and HbA1c levels. Logistic regression analysis was used to evaluate which glucometabolic factor has the strongest correlation with CAD severity.

Results

HbA1c was the only glucometabolic factor associated with SYNTAX score above 22 (OR = 3.03, CI 95 % 1.03–8.9, p = 0.04). HbA1c was also significantly associated with CAD severity in subgroup analysis (MI and stable angina).

Conclusions

In non-diabetic patients with myocardial infarction or stable angina, HbA1c levels correlate with CAD severity as measured by the SYNTAX score. No correlation was found between admission glucose or fasting glucose levels and CAD severity.     

Defining the relationship between plasma glucose and HbA(1c): analysis of glucose profiles and HbA(1c) in the Diabetes Control and Complications Trial

OBJECTIVE:To define the relationship between HbA(1c) and plasma glucose (PG) levels in patients with type 1 diabetes using data from the Diabetes Control and Complications Trial (DCCT). RESEARCH DESIGN AND METHODS: The DCCT was a multicenter, randomized clinical trial designed to compare intensive and conventional therapies and their relative effects on the development and progression of diabetic complications in patients with type 1 diabetes. Quarterly HbA(1c) and corresponding seven-point capillary blood glucose profiles (premeal, postmeal, and bedtime) obtained in the DCCT were analyzed to define the relationship between HbA(1c) and PG. Only data from complete profiles with corresponding HbA(1c) were used (n = 26,056). Of the 1,441 subjects who participated in the study, 2 were excluded due to missing data. Mean plasma glucose (MPG) was estimated by multiplying capillary blood glucose by 1.11. Linear regression analysis weighted by the number of observations per subject was used to correlate MPG and HbA(1c). RESULTS: Linear regression analysis, using MPG and HbA(1c) summarized by patient (n = 1,439), produced a relationship of MPG (mmol/l) = (1.98 . HbA(1c)) - 4.29 or MPG (mg/dl) = (35.6 . HbA(1c)) - 77.3, r = 0.82). Among individual time points, afternoon and evening PG (postlunch, predinner, postdinner, and bedtime) showed higher correlations with HbA(1c) than the morning time points (prebreakfast, postbreakfast, and prelunch). CONCLUSIONS: We have defined the relationship between HbA(1c) and PG as assessed in the DCCT. Knowing this relationship can help patients with diabetes and their healthcare providers set day-to-day targets for PG to achieve specific HbA(1c) goals.     

Targets and tactics: the relative importance of HbA1c,fasting and postprandial plasma glucose levels to glycaemic control in type 2 diabetes

Background: The incidence of type 2 diabetes is reaching pandemic proportions, impacting patients and healthcare systems across the globe. Evidence suggests that a majority of patients are not achieving recommended blood glucose targets resulting in an increased risk of micro‐ and macro‐vascular complications. Aim: To review literature on the significance of glycosylated haemoglobin (HbA_1c), fasting plasma glucose (FPG) and postprandial plasma glucose (PPG), their inter‐relationships and relative importance in the treatment of diabetes, and to provide practical guidance on effective monitoring of patients. Methods: Clinical guidelines on diabetes management and clinical and preclinical studies of glycaemic control identified through a publications database search were reviewed. Results: Glycaemic control remains fundamental to the successful management of diabetes. HbA_1c is the gold standard measure of glycaemic control but recent evidence suggests that postmeal hyperglycaemia also plays an important role in the aetiology of diabetes‐associated complications and control of PPG levels is vital to the achievement of recommended HbA_1c targets. Conclusions: The call for action on type 2 diabetes has never been more compelling; with a clear focus on strategies for glycaemic control, the impact of the diabetes pandemic can be limited.     

HbA_(1c)诊断2型糖尿病特性观察及在空腹血糖正常人群中的分布特征研究

目的观察糖化血红蛋白(HbA1c)诊断2型糖尿病(T2DM)的特点及其在空腹血糖(FPG)正常者中的分布情况。方法同时测定729例FPG正常者尿酸(UA)、甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C);用免疫抑制比浊法测定247例接受口服葡萄糖耐量试验(OGTT)者(包括T2DM 164例、糖耐量受损41例、空腹血糖受损18例、糖耐量正常者24例)的HbA1c,以OGTT和临床诊断结果作为标准,绘制HbA1c和FPG的受试者工作特征(ROC)曲线,确定HbA1c诊断T2DM的切点,通过对比分析观察不同性别及同性别不同年龄组中HbA1c的分布情况。结果免疫抑制比浊法测定HbA1c诊断T2DM的切点为6.36%,诊断灵敏度为86.50%、特异性为90.60%、阳性预测值为94.63%、阴性预测值为76.50%、曲线下面积为0.944[95%可信区间(CI):0.917~0.971],FPG7.0 mmol/L时诊断糖尿病的灵敏度为85.90%、特异性为93.80%、曲线下的面积为0.957[95%CI:0.932~0.981]。FPG正常者中女性HbA1c、HDL-C水平明显高于男性(P=0.000),男性血红蛋白(Hb)、FPG、UA、TG水平高于女性(P值分别为0.000、0.020、0.000、0.000)。随着年龄的增加,男、女性HbA1c、FPG、TC和LDL-C均有增高的趋势;特别是在60岁以后,女性HbA1c升高更高明显;但HDL-C在男性中有上升的趋势,在女性中有下降的趋势。结论免疫抑制比浊法测定HbA1c诊断T2DM的切点为6.36%,随着年龄的增加要定期测定HbA1c,以达到预防糖尿病的目的。     

Relationship between HbA1c level and peripheral arterial disease

OBJECTIVE: Homeostatic glucose control may play an important role in the development of peripheral arterial disease among individuals without diabetes. We sought to evaluate the association of HbA(1c) (A1C) with peripheral arterial disease in a representative sample of the U.S. population with and without diabetes. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted among 4,526 National Health and Nutrition Examination Survey 1999-2002 participants > or = 40 years of age. Peripheral arterial disease was defined as an ankle-brachial index <0.9 (n = 327). RESULTS: Among nondiabetic subjects, the age-standardized prevalence of peripheral arterial disease was 3.1, 4.8, 4.7, and 6.4% for participants with an A1C <5.3, 5.3-5.4, 5.5-5.6, and 5.7-6.0%, respectively (P trend <0.001). The prevalence of peripheral arterial disease was 7.5 and 8.8% for diabetic participants with A1C <7 and > or = 7%, respectively. After multivariable adjustment and compared with nondiabetic participants with A1C <5.3%, the odds ratio (95% CI) of peripheral arterial disease for nondiabetic participants with an A1C of 5.3-5.4, 5.5-5.6, and 5.7-6.0% was 1.41 (0.85-2.32), 1.39 (0.70-2.75), and 1.57 (1.02-2.47), respectively, and it was 2.33 (1.15-4.70) and 2.74 (1.25-6.02) for diabetic participants with A1C <7 and > or = 7%, respectively. CONCLUSIONS: An association exists between higher levels of A1C and peripheral arterial disease, even among patients without diabetes. Individuals with A1C levels > or = 5.3% should be targeted for aggressive risk factor reduction, which may reduce the burden of subclinical cardiovascular disease even among those without diabetes.     

Cardiometabolic risk profiles and carotid atherosclerosis in individuals with prediabetes identified by fasting glucose, postchallenge glucose, and hemoglobin A1c criteria

OBJECTIVE

We evaluated whether cardiometabolic risk profiles differ for subjects identified as having prediabetes by A1C, fasting glucose (FPG), or 2-h postchallenge glucose (2-PG) criteria.

RESEARCH DESIGN AND METHODS

Atherosclerosis risk factors, oral glucose tolerance test, and ultrasound measurement of carotid intima–media thickness (IMT) were analyzed in 780 nondiabetic individuals.

RESULTS

Poor agreement existed for A1C and FPG criteria for identification of subjects with prediabetes (κ coefficient = 0.332). No differences in cardiometabolic risk profiles were observed among the three groups of individuals with prediabetes by A1C only, FPG only, and both A1C and FPG. Poor agreement also existed for A1C and 2-PG criteria for identification of individuals with prediabetes (κ coefficient = 0.299). No significant differences in cardiometabolic risk factors were observed between IGT-only and individuals with prediabetes by A1C and 2-PG. Compared with subjects with prediabetes identified by A1C only, IGT-only individuals exhibited a worse cardiometabolic risk profile, with significantly higher systolic blood pressure, pulse pressure, 2-h postchallenge insulin, triglycerides, high-sensitivity C-reactive protein, and carotid IMT, and lower HDL cholesterol levels and insulin sensitivity.

CONCLUSIONS

These results suggest that considerable discordance between A1C, FPG, and 2-PG exists for the identification of individuals with prediabetes and that the cardiometabolic risk profile of these individuals varies by metabolic parameter, with 2-PG showing the stronger association with cardiometabolic risk factors and subclinical atherosclerosis than FPG or A1C.Hemoglobin A_1c (A1C) is an integrated measure of average blood glucose concentrations over the preceding 2–3 months and is widely used for monitoring metabolic control in individuals with diabetes (1). Recently, the American Diabetes Association (ADA) has revised criteria for the diagnosis of type 2 diabetes and the categories at increased risk for diabetes already including impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) on the basis of an ample analysis performed by an international expert committee (2,3) recommending the use of A1C measurements as another diagnostic test option in addition to glucose values. Specifically for the categories of increased risk for type 2 diabetes, the new ADA recommendations state that an A1C from 5.7 to 6.4% identifies individuals at high risk for diabetes to whom the term prediabetes may be applied (2).A1C measurements offer some practical advantages over assessments of fasting plasma glucose (FPG) or glucose levels during an oral glucose tolerance test (OGTT), including lower day-to-day variability, less perturbations during periods of stress or illness, and requirement of a nonfasting sample (3). However, the A1C measure may identify distinct subjects at increased risk for type 2 diabetes compared with IFG and IGT, and if extensively implemented, may to some extent change the present epidemiologic setting of these dysglycemic conditions. Although it would be desirable for fasting glucose, 2-h postchallenge glucose, and A1C values to be equivalent in identifying at-risk subjects, a poor concordance among the three prediabetes categories has been reported in different ethnic groups (4–10).Early detection of individuals at high risk for type 2 diabetes is essential not only for prevention of diabetes itself but also of the associated cardiovascular complications. Indeed, the risk of cardiovascular disease is already increased before glucose levels reach the diagnostic threshold of diabetes, and 2-h postchallenge glucose has been reported to be a better predictor of cardiovascular disease than FPG (11,12). However, A1C was shown to be a better predictor of cardiovascular disease than FPG (13). Head-to-head comparisons between 2-h postchallenge glucose and A1C as predictors of cardiovascular disease have been focused on mortality, and results are controversial (14–16).In consideration of the expected augmented use of A1C as a screening tool to identify individuals with dysglycemic conditions, it would be important to evaluate the effect of the new ADA recommendations for prediabetes definition on the ability to identify individuals who are at increased risk for a number of adverse clinical outcomes. In the current study, we examined the concordance of A1C, FPG, or 2-h postchallenge glucose tests for the identification of prediabetes in a cohort of Italian Caucasians. We also evaluated whether metabolic and cardiovascular risk factors, including carotid preclinical atherosclerosis, differ for subjects identified as having prediabetes by each of these criteria.     

糖化血红蛋白联合空腹血糖筛查2型糖尿病高危人群的临床意义

目的了解糖化血红蛋白(HbA1c)筛查糖尿病和糖代谢受损的敏感性并与空腹血糖(FBG)进行比较。方法对400例无糖尿病病史的糖尿病高危人群同时检测FBG和HbA1c,据空腹血糖水平分为三组:A1组:FBG<6.1 mmol/L,计336例,A2组:FBG 6.1-6.9 mmol/L,45例,A3组FBG≥7.0 mmol/L,19例。结果 (1)400例人群中,HbA1c≥6.0%,88例,异常率为22.0%;FBG≥6.1mmol/L,54例,异常率13.5.%,HbA1c的异常率高于FBG,P<0.05。(2)A1组HbA1c>≥6.0%,29例,占8.6%;A2组HbA1c≥6.0%,41例,占91.1%;A3组HbA1c≥6.0%,18例,占94.7%;(3)400例人群中,HbA1c≥6.0%或FBG≥6.1mmol/L,93例,异常率23.3%%。结论 HbA1c筛查糖尿病高危人群血糖异常的敏感性高于空腹血糖,两者联合检查有助发现更多糖代谢异常的患者。     

Results of blood inflammatory markers are associated more strongly with toe-brachial index than with ankle-brachial index in patients with type 2 diabetes

OBJECTIVE: Three blood markers of inflammation (high-sensitivity C-reactive protein [hsCRP], interleukin [IL]-6, and fibrinogen) were compared with markers of atherosclerotic cardiovascular disease (CVD) (history of stroke or cardiac ischemia and measured toe-brachial index [TBI]) to determine whether inflammatory markers are associated with atherosclerosis in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Of 103 patients with type 2 diabetes, 26 had CVD. TBI was plethysmographically determined in both great toes. Serum hsCRP was immunonephelometrically determined. Plasma IL-6 was measured by an enzyme immunoassay. RESULTS: Both ABI and TBI were lower in diabetic patients with CVD than in those without CVD (1.05 +/- 0.19 vs. 1.14 +/- 0.09, P < 0.05, and 0.75 +/- 0.20 vs. 0.95 +/- 0.21, P < 0.001, respectively). By linear regression, right TBI but not right ABI showed a significant negative correlation with serum hsCRP (r = -0.372, P < 0.01) and plasma fibrinogen (r = -0.224, P < 0.05). Serum hsCRP was also negatively correlated with lower TBI, but not lower ABI. We found no significant correlation between plasma IL-6 and ABI or TBI. CONCLUSIONS: TBI was strongly associated with CVD, serum hsCRP, and plasma fibrinogen. Of these inflammatory markers, serum hsCRP may be the most promising marker for vascular inflammation.