Screening for type 2 diabetes and impaired glucose metabolism: the Australian experience

OBJECTIVE: To assess the Australian protocol for identifying undiagnosed type 2 diabetes and impaired glucose metabolism. RESEARCH DESIGN AND METHODS: The Australian screening protocol recommends a stepped approach to detecting undiagnosed type 2 diabetes based on assessment of risk status, measurement of fasting plasma glucose (FPG) in individuals at risk, and further testing according to FPG. The performance of and variations to this protocol were assessed in a population-based sample of 10,508 Australians. RESULTS: The protocol had a sensitivity of 79.9%, specificity of 79.9%, and a positive predictive value (PPV) of 13.7% for detecting undiagnosed type 2 diabetes and sensitivity of 51.9% and specificity of 86.7% for detecting impaired glucose tolerance (IGT) or impaired fasting glucose (IFG). To achieve these diagnostic rates, 20.7% of the Australian adult population would require an oral glucose tolerance test (OGTT). Increasing the FPG cut point to 6.1 mmol/l (110 mg/dl) or using HbA(1c) instead of FPG to determine the need for an OGTT in people with risk factors reduced sensitivity, increased specificity and PPV, and reduced the proportion requiring an OGTT. However, each of these protocol variations substantially reduced the detection of IGT or IFG. CONCLUSIONS: The Australian screening protocol identified one new case of diabetes for every 32 people screened, with 4 of 10 people screened requiring FPG measurement and 1 in 5 requiring an OGTT. In addition, 1 in 11 people screened had IGT or IFG. Including HbA(1c) measurement substantially reduced both the number requiring an OGTT and the detection of IGT or IFG.     

Utility of hemoglobin A1c for the identification of individuals with diabetes and prediabetes in a Chinese high risk population

Abstract Background. The aim of the study was to assess the utility of Hemoglobin A1c (HbA1c) to identify individuals with undiagnosed DM and prediabetes (preDM) in the high risk population of Chinese people. Methods. A total of 424 high risk individuals without known diabetes, who met at least three of the high risk factors for DM (hypertension, abnormal blood lipid, family history of DM and high BMI) were selected for this study, HbA1c, fasting plasma concentrations of glucose (FPG) and a 75 g oral glucose tolerance test (OGTT) were measured. The performance of HbA1c in relation to undiagnosed DM and preDM investigated through receiver operating characteristic (ROC) curves, the reference for DM and preDM, are according to the 2011 WHO-FPG/OGTT criteria and the appropriate cut-off points of HbA1c for DM and preDM were assessed. The properties of HbA1c diagnosing DM and preDM were also compared with that of the fasting plasma glucose (FPG). Results. It was shown that the AUC (area under the curve) of the ROC curve for HbA1c predicting undiagnosed DM was similar to that of FPG, and the cut-off point of HbA1c 6.2% was optimal for predicting DM, with a sensitivity of 66%, and a specificity of 91%. Furthermore, the cut-off point of HbA1c was 5.9% for preDM with a sensitivity of 70%, a specificity of 87%. Conclusion. Collectively, this study found that the measurement of HbA1c may be efficient to diagnosis undiagnosed both DM and preDM with the cut-off point of 6.2% and 5.9%, respectively.     

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。     

糖化血红蛋白对糖尿病的诊断价值分析

目的探讨糖化血红蛋白（HbA1c）在糖尿病（DM）诊断中的应用价值。方法 286例健康人和680例DM患者均行口服葡萄糖耐量试验（OGTT）,用特定蛋白分析仪检测HbA1c水平,用BS-420生化分析仪测定血糖,对结果进行分析。结果从健康组到DM组之间的HbA1c的变化关系可看出：DM组患者空腹血糖（FPG）、餐后2h血糖（2hPG）及HbA1c均明显高于健康组（均P〈0.01）,以HbA1c≥6.5%作为DM诊断临界值,其诊断灵敏度为99.18%,诊断特异性为94.45%,均优于以FPG≥7.0mmol/L作为诊断临界值的诊断灵敏度（76.43%）和诊断特异性（89.82%）。结论 HbA1c的值为6.5%时用于诊断DM,与FPG≥7.0mmol/L时联合应用可增加诊断DM的能力。     

HbA1c measurement improves the detection of type 2 diabetes in high-risk individuals with nondiagnostic levels of fasting plasma glucose: the Early Diabetes Intervention Program (EDIP)

OBJECTIVE: Whereas new diagnostic criteria based on a fasting plasma glucose (FPG) of > 126 mg/dl (7.8 mmol/l) have improved the detection of diabetes, multiple reports indicate that many people with diabetes diagnosed by 2-h oral glucose tolerance test (OGTT) glucose measurements > or = 11.1 mmol/l (200 mg/dl) would remain undiagnosed based on this FPG criteria. Thus, improved methods to detect diabetes are particularly needed for high-risk individuals. We evaluated whether the combination of FPG and HbA1c measurements enhanced detection of diabetes in those individuals at risk for diabetes with nondiagnostic or minimally elevated FPG. RESEARCH DESIGN AND METHODS: We analyzed FPG, OGTT, and HbA1c data from 244 subjects screened for participation in the Early Diabetes Intervention Program (EDIP). RESULTS: Of 244 high-risk subjects studied by FPG measurements and OGTT, 24% of the individuals with FPG levels of 5.5-6.0 mmol/l (100-109 mg/dl) had OGTT-diagnosed diabetes, and nearly 50% of the individuals with FPG levels of 6.1-6.9 mmol/l (110-125 mg/dl) had OGTT-diagnosed diabetes. In the subjects with OGTT-diagnosed diabetes and FPG levels between 5.5 and 8.0 mmol/l, detection of an elevated HbA1c (>6.1% or mean + 2 SDs) led to a substantial improvement in diagnostic sensitivity over the FPG threshold of 7.0 mmol/l (61 vs. 45%, respectively, P = 0.002). Concordant FPG levels > or = 7.0 mmol/l (currently recommended for diagnosis) occurred in only 19% of our cohort with type 2 diabetes. CONCLUSIONS: Diagnostic criteria based on FPG criteria are relatively insensitive in the detection of early type 2 diabetes in at-risk subjects. HbA1c measurement improves the sensitivity of screening in high-risk individuals.     

糖化血红蛋白在早孕期糖尿病筛查中的意义

目的：探讨糖化血红蛋白（HbA1c）在早孕期糖尿病（GDM）筛查中的意义。方法正常组120例、糖耐量异常组59例及糖尿病组78例,在妊娠20周时分别进行空腹血糖（FPG）、75g葡萄糖耐量实验（OGTT）和HbA1c测定。结果糖尿病组FPG,OGTT,HbA1c水平均高于正常组（P〈0.01）,HbA1c在糖耐量异常组及糖尿病组中的阳性率分别为96.7%、98.7%。结论 HbA1c在GDM筛查中的诊断效率明显高于FPG和OGTT,可作为临床GDM早孕期筛查诊断的指标。     

Fasting plasma glucose and hemoglobin A1c in identifying and predicting diabetes: the strong heart study

OBJECTIVE: To compare fasting plasma glucose (FPG) and HbA(1c) in identifying and predicting type 2 diabetes in a population with high rates of diabetes. RESEARCH DESIGN AND METHODS: Diabetes was defined as an FPG level ≥ 126 mg/dL or an HbA(1c) level ≥ 6.5%. Data collected from the baseline and second exams (1989-1995) of the Strong Heart Study were used. RESULTS For cases of diabetes identified by FPG ≥ 126 mg/dL, using HbA(1c) ≥ 6.5% at the initial and 4-year follow-up diabetes screenings (or in identifying incident cases in 4 years) among undiagnosed participants left 46% and 59% of cases of diabetes undetected, respectively, whereas for cases identified by HbA(1c) ≥ 6.5%, using FPG ≥ 126 mg/dL left 11% and 59% unidentified, respectively. Age, waist circumference, urinary albumin-to-creatinine ratio, and baseline FPG and HbA(1c) levels were common significant risk factors for incident diabetes defined by either FPG or HbA(1c); triglyceride levels were significant for diabetes defined by HbA(1c) alone, and blood pressure and sibling history of diabetes were significant for diabetes defined by FPG alone. Using both the baseline FPG and HbA(1c) in diabetes prediction identified more people at risk than using either measure alone. CONCLUSIONS Among undiagnosed participants, using HbA(1c) alone in initial diabetes screening identifies fewer cases of diabetes than FPG, and using either FPG or HbA(1c) alone cannot effectively identify diabetes in a 4-year periodic successive diabetes screening or incident cases of diabetes in 4 years. Using both criteria may identify more people at risk. The proposed models using the commonly available clinical measures can be applied to assessing the risk of incident diabetes using either criterion.     

Costs of screening for pre-diabetes among US adults: a comparison of different screening strategies

OBJECTIVE: We evaluated various strategies to identify individuals aged 45-74 years with pre-diabetes (either impaired glucose tolerance or impaired fasting glucose). RESEARCH DESIGN AND METHODS: We conducted a cost analysis to evaluate the effectiveness (proportion of cases identified), total costs, and efficiency (cost per case identified) of five detection strategies: an oral glucose tolerance test (OGTT), a fasting plasma glucose (FPG) test, an HbA(1c) test, a capillary blood glucose (CBG) test, and a risk assessment questionnaire. For the first strategy, all individuals received an OGTT. For the last four strategies, only those with a positive screening test received an OGTT. Data were from the Third U.S. National Health and Nutrition Examination Survey, 2000 census, Medicare, and published literature. One-time screening costs were estimated from both a single-payer perspective and a societal perspective. RESULTS: The proportion of pre-diabetes and undiagnosed diabetes identified ranged from 69% to 100% (12.1-17.5 million). The cost per case identified ranged from US dollars 176 to US dollars 236 from a single-payer perspective and from US dollars 247 to US dollars 332 from a societal perspective. Testing all with OGTT was the most effective strategy, but the CBG test and risk assessment questionnaire were the most efficient. If people are substantially less willing to take an OGTT than a FPG test, then the FPG testing strategy was the most effective strategy. CONCLUSIONS: There is a tradeoff between effectiveness and efficiency in choosing a strategy. The most favorable strategy depends on if the goal of the screening program is to identify more cases or to pursue the lowest cost per case. The expected percentage of the population willing to take an OGTT is also a consideration.     

Macrovascular risk and diagnostic criteria for type 2 diabetes: implications for the use of FPG and HbA(1c) for cost-effective screening

OBJECTIVE: The use of fasting plasma glucose (FPG) level > or =7.0 mmol/l leads to underdiagnosis of type 2 diabetes compared with the oral glucose tolerance test (OGTT). The OGTT is of limited use for population screening. Most of the increase in cardiovascular risk in relation to increasing blood glucose occurs before the threshold at which the diagnosis of type 2 diabetes is made. The aim of this study was to evaluate the use of HbA(1c) and FPG as predictors of type 2 diabetes and cardiovascular risk and, accordingly, to develop a rational approach to screening for abnormalities of glucose tolerance. RESEARCH DESIGN AND METHODS: OGTT and measurement of HbA(1c) and FPG levels were performed in 505 subjects screened for type 2 diabetes. Anthropomorphic measurements were obtained. A cardiovascular risk factor questionnaire was completed. RESULTS: The subjects were aged 19-88 years (mean 53.8). The incidence of type 2 diabetes was 10.4% based on the OGTT and 4% based on an FPG level > or =7.0 mmol/l. Using high-performance liquid chromatography (HPLC), HbA(1c) of <4.7 and > or =6.2% predicted with certainty the absence or presence of type 2 diabetes as defined by the OGTT. The corresponding cutoffs were <5.0 and > or =6.8% for HbA(1c) (DCA2000 HPLC device; Bayer Diagnostics, Mulgrave, Australia) and <4.7 and > or =6.4 mmol/l for FPG. However, 75-85% of subjects in each case had intermediate values, which were therefore nondiagnostic. Cardiovascular risk increased at least 2.2 times at an HbA(1c) level > or =6.2% (by HPLC), 1.8-2.2 times at an HbA(1c) level of 5.6-6.1% (by HPLC), 2 times at an FPG level > or =6.4 mmol/l, and 1.7-1.9 times at an FPG level of 5.6-6.3 mmol/l. CONCLUSIONS: Measurement of FPG and HbA(1c) levels will diagnose or exclude type 2 diabetes with certainty in a minority (15%) of people. There is a continuous relationship between FPG and HbA(1c) and cardiovascular risk. Accordingly, we propose that there is a rational basis for using either FPG and HbA(1c) for purposes of screening and assigning risk. Individuals with an HbA(1c) level of 5.6-6.1% and an FPG level of 5.6-6.3 mmol/l are at greatest risk for cardiovascular disease and should be targeted for further evaluation. An algorithm outlining a cost-effective approach is presented.     

Screening for type 2 diabetes with random finger‐prick glucose and bedside HbA1c in an Australian emergency department

Objective: To determine if screening for undiagnosed type 2 diabetes mellitus (T2DM) and pre‐diabetes is feasible in an Australian ED; to estimate the prevalence of T2DM and pre‐diabetes in the Australian ED population. Methods: Prospective cross‐sectional prevalence survey in the ED of St Vincent's Hospital, Melbourne, an adult, tertiary referral centre seeing approximately 40 000 patients annually. A convenience sample of adult patients was screened with finger‐prick random blood glucose and glycosylated haemoglobin (HbA1c); those over 6.0 mmol/L and 6.0% were referred for oral glucose tolerance test (OGTT). Diagnoses of T2DM and pre‐diabetes were made according to World Health Organization definitions. Those not attending for OGTT were contacted by phone, and interviewed about their reasons. Results: Seven hundred and twenty‐five patients were recruited; 135 (18.6%; 95% confidence intervals [CI] 15.9–21.6%) had known T2DM, leaving 590 screened, of whom 210 screened positive. Of the 192 referred for OGTT, 147 (77%) did not attend despite several telephone reminders. Of the 45 (23%) completing OGTT, pre‐diabetes was present in eight (17.8%; 95% CI 9.0–31.6%) and T2DM in six (13.3%; 95% CI 5.9–26.6%). Many people interviewed (18/86, 21%) did not attend for OGTT on the advice of their doctors. Conclusions: This inner city tertiary ED has a high prevalence of T2DM, diagnosed and undiagnosed, with as much as half our population possibly affected. Although ED screening might have a high yield, opportunistic screening is not feasible, with difficulties in staff engagement and patient follow up for diagnostic testing. Future studies might consider finger‐prick fasting blood glucose through a patient's general practitioner for diagnosis.     

Predictive value of first fasting plasma glucose compared with admission plasma glucose for undiagnosed diabetes in a stable cardiology population

ObjectivesThe study compared the predictive value of admission plasma glucose (APG) and first fasting plasma glucose (FPG) in stratifying patients meriting an oral glucose tolerance test (OGTT).Design and methodsCharacteristics of APG, FPG and OGTT 2-hour glucose as well as other blood measurements, physical examinations and medical information were assessed in 994 patients without known diabetes.ResultsThe prevalences of diabetes and impaired glucose tolerance were 24.6% and 37.9%, according to an OGTT, respectively. The first FPG demonstrated stronger predictive value in diagnosing diabetes than APG did both in overall and in patients with less clinical value. Compared to the first FPG, APG provided less value to coronary artery disease, hypertension and high-sensitivity C-reactive protein for diabetes screening.ConclusionsThe first FPG exerted more predictive value than APG did and was still a preferable reference prior to APG in stratifying patients for undiagnosed diabetes by an OGTT.     

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。     

HbA1c对糖调节受损和2型糖尿病的诊断价值

摘要：目的：评估糖化血红蛋白（HbA1c）不同cut off值诊断2型糖尿病（T2DM）的效能,初步探讨美国糖尿病协会（ADA）推荐的HbA1c诊断T2DM及T2DM前期标准对中国人的适用性。 方法：招募接受口服葡萄糖耐量（OGTT）试验且试验前未诊治为T2DM的志愿者338例,用高效液相色谱法检测HbA1c;以WHO标准诊断糖调节受损（IGR）、糖耐量正常和T2DM;用受试者工作特征（ROC）曲线分析不同 cut off值HbA1c诊断IGR和T2DM的效能。 结果：HbA1c在诊断T2DM时,ROC曲线下面积（AUC^ROC）为0.954,最佳cut off值为6.0%,敏感性为92.5%,特异性为86.0%;当HbA1c为6.5%时,敏感性为64.8%,特异性为96.7%;当HbA1c为5.6%时,诊断T2DM阴性预测值为100.0%;HbA1c诊断IGR的AUC^ROC为0.653。 结论: HbA1c用于IGR的诊断效能不高;HbA1c诊断T2DM最佳cut off值为6.0%,此界值诊断敏感性较FPG高,但特异性较差;ADA推荐用于T2DM诊断的cut off值6.5%主要考虑到诊断的特异性,该诊断标准适用于中国人群。     

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.     

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。     

Using HbA(1c) to improve efficacy of the american diabetes association fasting plasma glucose criterion in screening for new type 2 diabetes in American Indians: the strong heart study

OBJECTIVE: To find an optimal critical line in the fasting plasma glucose (FPG)-HbA(1c) plane for identifying diabetes in participants with impaired fasting glucose (IFG) and thereby improve the efficacy of using FPG alone in diabetes screening among American Indians. RESEARCH DESIGN AND METHODS: We used FPG, 2-h postload glucose (2hPG), and HbA(1c) measured in the 2,389 American Indians (aged 45-74 years, without diabetes treatment or prior history of diabetes) in the Strong Heart Study (SHS) baseline (second) examination. Participants were classified as having diabetes if they had either FPG > or =126 mg/dl or 2hPG > or =200 mg/dl, as having IFG if they had 110 < or = FPG < 126 mg/dl, and as having normal fasting glucose (NFG) if they had FPG <110, according to the American Diabetes Association (ADA) definition. Logistic regression models were used for identifying diabetes (2hPG > or =200 mg/dl) in IFG participants. The areas under the receiver operating characteristic (ROC) curves generated by different logistic regression models were evaluated and compared to select the best model. A utility function based on the best model and the cost-to-benefit ratio was used to find the optimal critical line. The data from the second examination were used to study the effect of the time interval between the successive diabetes screenings on both the FPG criterion and the optimal critical line. RESULTS: A total of 37% of all subjects with new diabetes at baseline and 55.2% of those in the second exam had 2hPG > or =200 but FPG <126. There was a very large portion of IFG participants with diabetes (19.3 and 22.9% in the baseline and second exam, respectively). Among the areas under the ROC curves, the area generated by the logistic regression model on FPG plus HbA(1c) is the largest and is significantly larger than that based on FPG (P = 0.0008). For a cost-to-benefit ratio of 0.23888, the optimal critical line that has the highest utility is: 0.89 x HbA(1c) + 0.11 x FPG = 17.92. Those IFG participants whose FPG and HbA(1c) were above or on the line were referred to take an oral glucose tolerance test (OGTT) to diagnose diabetes. The optimal critical line is lower if a successive diabetes screening will be conducted 4 years after the previous screening. CONCLUSIONS: FPG > or =126 and 2hPG > or =200, as suggested by the ADA, are used independently to define diabetes. The FPG level is easy to obtain, and using FPG alone is suggested for diabetes screening. It is difficult to get physicians and patients to perform an OGTT to get a 2hPG level because of the many drawbacks of the OGTT, especially in those patients who already have FPG <126. It is also impractical to conduct an OGTT for everyone in a diabetes screening. Our data show that 37% of all subjects with new diabetes in the SHS baseline exam and 55.2% of those in the second exam have 2hPG > or =200 but FPG <126. These cases of diabetes cannot be detected if FPG is used alone in a diabetes screening. Therefore, although the small portion of diabetes in the NFG group (4.7% in the baseline and 6.9% in the second exam) may be ignored, those cases of diabetes among IFG participants ( approximately 20% in our data) need further consideration in a diabetes screening. It may be worthwhile for those IFG participants identified by the optimal critical line to take an OGTT. The optimal critical line and time interval between successive diabetes screenings need further study.     

Detection of undiagnosed diabetes and other hyperglycemia states: the Atherosclerosis Risk in Communities Study

OBJECTIVE: To evaluate screening strategies based on fasting plasma glucose (FPG), clinical information, and the oral glucose tolerance test (OGTT) for detection of diabetes or other hyperglycemic states-impaired fasting glucose (IFG) and impaired glucose tolerance-meriting clinical intervention. RESEARCH DESIGN AND METHODS: We studied 8,286 African-American and white men and women without known diabetes, aged 53-75 years, who received an OGTT during the fourth exam of the Atherosclerosis Risk in Communities Study. Using a split sample technique, we estimated the diagnostic properties of various clinical detection rules derived from logistic regression modeling. Screening strategies utilizing FPG, these detection rules, and/or the OGTT were then compared in terms of both the fraction of hyperglycemia cases detected and the sample fraction receiving different screening tests and identified as screen positive. RESULTS: Screening based on the IFG cut point (> or =6.1 mmol/l), followed by a clinical detection rule for those below this value, detected 86.3% of diabetic case subjects and 66.0% of all hyperglycemia cases, identifying 42% of the sample as screen positive. Applying an OGTT for those positive by the rule provides diagnostic labeling and reduces the fraction that is screen positive to 29%. Another strategy, to apply an OGTT to those with an FPG cut point between 5.6 and 6.1 mmol/l, also identifies 29% of the sample as screen positive, although it detects slightly fewer hyperglycemia cases. CONCLUSIONS: Screening strategies based on FPG, complemented by clinical detection rules and/or an OGTT, are effective and practical in the detection of hyperglycemic states meriting clinical intervention.     

糖化血红蛋白和血糖水平检测对精神病患者并发糖尿病的诊断价值

目的探讨糖化血红蛋白(HbA1c)、空腹血糖(FPG)、葡萄糖耐量试验(OGTT)2 h血糖检测对精神病并发糖尿病诊断的临床价值。方法收集重庆市精神卫生中心歌乐山院区老年科及综合科107例精神病并发糖尿病患者纳入观察组,110例非糖尿病的精神病患者纳入疾病对照组,100例职工健康体检者纳入健康对照组。采集血清及抗凝全血标本,采用己糖激酶法测定FPG、OGTT 2 h血糖,采用液相色谱离子交换层析法检测HbA1c水平,比较3组研究对象各项指标水平,并分析观察组各项指标相关性及并发症发生情况。结果观察组患者的FPG、OGTT 2 h血糖、HbA1c水平均明显高于疾病对照组和健康对照组,差异有统计学意义(P<0.05);疾病对照组和健康对照组的FPG、OGTT 2 h血糖、HbA1c水平比较,差异无统计学意义(P>0.05)。观察组中,FPG与HbA1c呈显著正相关(r=0.591,P<0.05);OGTT 2 h血糖水平与HbA1c水平呈显著正相关(r=0.564,P<0.05)。HbA1c>8%患者相关并发症的发生率均明显高于HbA1c≤8%患者,差异有统计学意义(P<0.05)。结论FPG、OGTT和HbA1c水平检测可作为诊断精神病患者并发糖尿病的一项重要指标,且对并发症发生风险具有重要的评估价值。     

American Diabetes Association diabetes diagnostic criteria, advancing age, and cardiovascular disease risk profiles: results from the Third National Health and Nutrition Examination Survey

OBJECTIVE: To evaluate age-specific effects on diabetes prevalence estimates resulting from the American Diabetes Association (ADA) recommendation against use of the oral glucose tolerance test (OGTT), we contrasted the prevalence of two mutually exclusive groups: undiagnosed diabetes according to ADA criteria (no report of diabetes and fasting glucose [FG] > or =126 mg/dl) and isolated postchallenge hyperglycemia (IPH) (FG <126 mg/dl and OGTT > or =200 mg/dl), a group designated to have diabetes by World Health Organization (WHO) criteria but not ADA criteria. RESEARCH DESIGN AND METHODS: The weighted age-specific ratios of undiagnosed diabetes:IPH were calculated for 2,844 subjects aged 40-74 years without reported diabetes who had both FG and OGTT. A ratio > 1.0 indicated that the proportion of undiagnosed diabetes was greater than that of IPH. Mean levels of HbA1c and cardiovascular disease (CVD) risk factors were contrasted among people with undiagnosed diabetes and IPH and those without either abnormality ("nondiabetic"). RESULTS: Both undiagnosed diabetes and IPH increased with age, but age-specific undiagnosed diabetes:IPH ratios decreased from 5.49 in the 40-44 age-group to 0.77 in the 70-74 age-group. Regression analysis showed a significant (P = 0.006) negative association between age and these ratios. Mean HbA1c was 7.1% in the undiagnosed diabetes group and differed significantly from that of the IPH and nondiabetic groups (5.6 and 5.3%, respectively). Individuals with undiagnosed diabetes had less favorable triglycerides, BMI, and HDL cholesterol compared with people with IPH. CONCLUSIONS: Compared with WHO criteria, the ADA criteria underestimate glucose abnormalities more with increasing age. However, compared to those with undiagnosed diabetes, individuals with IPH had a mean HbA1c level that is considered in the nondiabetic range, and this group had significantly more favorable levels of several key CVD risk factors. These findings suggest that the ADA criteria, although underestimating the abnormalities of postchallenge hyperglycemia that occur frequently with increasing age, appear to be effective at identifying a group of individuals with both unfavorable CVD risk factor profiles and evidence of long-term exposure to hyperglycemia.     

初诊2型糖尿病患者尿微量白蛋白/肌酐比值异常的发生率及危险因素分析

目的 分析初诊2型糖尿病患者尿微量白蛋白/肌酐比值(ACR)异常的发生率及危险因素.方法 2008年9月至2009年12月我院内分泌科收治的初诊2型糖尿病患者245例,测定空腹血糖(FPG),葡萄糖耐量试验、血脂、肾功能及尿ACR等.分别根据患者年龄、糖化血红蛋白(HbA1c)及尿ACR水平进行分层.采用t检验、方差分析、多元逐步回归分析等方法进行统计学分析.结果 ①本研究人群中,尿ACR的异常率为21.6%,其中微量白蛋白尿20.4%,大量白蛋白尿1.2%.②不同年龄组患者尿ACR水平＜40岁组(26.4±34.2)mg/g、≥40～50岁组(33.7±68.5)mg/g、≥50～59岁组(38.6±94.9)mg/g、≥60～69岁组(33.9±60.8)mg/g、≥70岁组(48.9±62.4)mg/g,差异无统计学意义(F=0.400,P＞0.05).③异常尿ACR组FPG、收缩压(SBP)、甘油三酯(TG)、体质量指数(BMI)显著高于正常尿ACR组患者(t值分别为-2.547、-2.144、-2.113、-4.663,P＜0.05或＜0.01),高密度胆固醇(HDL-C)显著低于正常尿ACR组(t=2.216,P＜0.05).④HbA1 c≥6.5%组的尿ACR水平与HbA1c＜6.5%组的差异无统计学意义(t=0.475,P＞0.05),HbA1 c≥6.5%组患者合并高血压的尿ACR水平显著高于血压正常患者(t=-2.472,P＜0.05).HbA1c＜6.5%组患者尿ACR比值水平与BMI、FPG呈正相关(r值分别为0.564、0.559,均P＜0.05);HbA1c≥6.5%组尿ACR水平与SBP、舒张压(DBP)和FPG呈正相关(r值分别为0.186、0.169、0.182,均P＜0.05);⑤多元逐步线性回归分析结果,影响尿ACR的主要因素包括FPG、SBP、肌酐(Cr).结论 初诊2型糖尿病患者尿ACR水平异常的发生不受年龄的影响,与血压及FPG有关.