Controlling the diabetes epidemic: how should we screen for undiagnosed diabetes and dysglycaemia?

AIMS: To compare the detection of undiagnosed diabetes and dysglycaemia (impaired glucose tolerance, impaired fasting glucose, diabetes) using risk factors and laboratory measures of glycaemia. METHODS: Casual blood glucose samples were taken from 1899 (69.4% of 2737 invited) European, Maori and Pacific Islands subjects aged 40-79 years from randomly selected households in South Auckland, New Zealand. Of these, 534 attended for a 75-g oral glucose tolerance test (OGTT) if an elevated result was identified [327/478 (68.4%)] or if randomly selected with a 'normal' screening result [207/308 (67.2%)]. RESULTS: Several Europeans with undiagnosed diabetes (25.0%) and dysglycaemia (31.4%) had no diabetes risk factors. Most Maori and Pacific Islanders had at least one risk factor. The area under the receiver operating curve (ROC) for the detection of undiagnosed diabetes was 0.92 (0.89-0.95) using fasting glucose, 0.86 (0.82-0.90) using HbA1c, 0.75 (0.69-0.80) using random glucose, but 0.60 (0.55-0.66) using risk factor screening. The ROC for detecting any dysglycaemia was 0.88 (0.85-0.90), 0.68 (0.64-0.71), 0.72 (0.69-0.75), 0.61 (0.58-0.65), respectively. Screening using fasting glucose (the best test) detected 90.4% of new diabetes and 78.4% of dysglycaemia; risk factor screening followed by fasting glucose detected significantly less cases [88 (82-93)% and 86 (82-89)%, respectively] with 9.2% less OGTTs. CONCLUSIONS: Using risk factors for the identification of who should receive a blood test for dysglycaemia adds little to direct screening with the risk of missing some with significant hyperglycaemia. Screening for dysglycaemia may best be undertaken using blood tests without initial risk factor symptom screening.     

Comparison of ADA and WHO screening methods for diabetes mellitus in obese patients. American Diabetes Association.

AIMS: To compare the performance of fasting glycaemia (FG) and oral glucose tolerance testing (OGTT) in screening for diabetes mellitus in obese patients. METHODS: A consecutive series of 528 (445 female, 83 male) obese (body mass index > 30 kg/m2) outpatients, aged 45.2 +/- 14.3 years, was studied with FG and OGTT. The association of categories of glucose tolerance (diabetes and impaired glucose tolerance (IGT)) and fasting glycaemia (diabetes and impaired fasting glucose (IFG)) with hypertension and hyperlipidaemia were also assessed. RESULTS: Prevalence of diabetes and IGT were 20.1 and 22.9%, respectively. FG (> 7 mmol/l) had a sensitivity of 56.7%. Using FG > 6.1 mmol/l, and OGTT in those above the threshold, the sensitivity for diabetes would have been 89.6%, with a positive predictive value of 59.0%, but 68.8% of cases of IGT would not have been detected. Patients with impaired fasting glucose (FG of 6.1-7.0 mmol/l) showed lower insulin sensitivity and impaired beta cell function, and a weaker association to hypertriglyceridaemia, when compared to IGT. CONCLUSION: FG > 7.0 mmol/l does not show a sufficient sensitivity for the screening of diabetes in obese patients. FG > 6. mmol/l has a satisfactory sensitivity for diabetes, but not for IGT. IFG has different pathophysiological features than IGT and cannot be assumed to have the same prognostic value of IGT.     

A multivariate logistic regression equation to screen for dysglycaemia: development and validation.

AIMS: To develop and validate an empirical equation to screen for dysglycaemia [impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and undiagnosed diabetes]. METHODS: A predictive equation was developed using multiple logistic regression analysis and data collected from 1032 Egyptian subjects with no history of diabetes. The equation incorporated age, sex, body mass index (BMI), post-prandial time (self-reported number of hours since last food or drink other than water), systolic blood pressure, high-density lipoprotein (HDL) cholesterol and random capillary plasma glucose as independent covariates for prediction of dysglycaemia based on fasting plasma glucose (FPG)>or=6.1 mmol/l and/or plasma glucose 2 h after a 75-g oral glucose load (2-h PG)>or=7.8 mmol/l. The equation was validated using a cross-validation procedure. Its performance was also compared with static plasma glucose cut-points for dysglycaemia screening. RESULTS: The predictive equation was calculated with the following logistic regression parameters: P=1+1/(1+e-X)=where X=-8.3390+0.0214 (age in years)+0.6764 (if female)+0.0335 (BMI in kg/m2)+0.0934 (post-prandial time in hours)+0.0141 (systolic blood pressure in mmHg)-0.0110 (HDL in mmol/l)+0.0243 (random capillary plasma glucose in mmol/l). The cut-point for the prediction of dysglycaemia was defined as a probability>or=0.38. The equation's sensitivity was 55%, specificity 90% and positive predictive value (PPV) 65%. When applied to a new sample, the equation's sensitivity was 53%, specificity 89% and PPV 63%. CONCLUSIONS: This multivariate logistic equation improves on currently recommended methods of screening for dysglycaemia and can be easily implemented in a clinical setting using readily available clinical and non-fasting laboratory data and an inexpensive hand-held programmable calculator.     

稳定型冠心病及合并糖尿病危险因素的高血压患者糖代谢异常筛查

目的调查在心内科门诊中既往无糖代谢异常病史的稳定型冠心病及合并糖尿病危险因素的高血压患者的糖代谢异常发生情况。方法对入选患者进行空腹或餐后毛细血管血糖检测,空腹血糖≥6.1 mmol/L或餐后随机血糖≥7.8 mmol/L的患者再进行口服葡萄糖耐量试验(OGTT)。结果共1412例患者进行毛细血管血糖检测,其中939例患者进行空腹血糖检测,281例(29.9%)患者空腹血糖≥6.1 mmol/L并且<7.0 mmol/L,105例(11.2%)患者空腹血糖≥7.0 mmol/L;473例患者进行餐后随机血糖检测,123例(26.0%)患者随机血糖≥7.8 mmol/L并且<11.1 mmol/L,43例(9.1%)患者随机血糖≥11.1 mmol/L。入选患者共552例(39.1%)毛细血管空腹血糖≥6.1 mmol/L或随机血糖≥7.8 mmol/L,其中298例患者又进行了OGTT,正常糖耐量(NGT)66例(22.1%),糖调节受损(IGR)132例(44.3%),其余100例(33.6%)患者新诊断为糖尿病。结论对既往无糖代谢异常病史的稳定型冠心病及合并糖尿病危险因素的高血压患者进行毛细血管血糖筛查及OGTT有助于早期发现糖代谢异常。     

Cardiovascular risk profile assessment in glucose‐intolerant Asian individuals—an evaluation of the World Health Organization two‐step strategy: the DECODA Study (Diabetes Epidemiology: Collaborative Analysis of Diagnostic Criteria in Asia)

Aims To assess the cardiovascular (CVD) risk factor profile in individuals with diabetes and impaired glucose tolerance (IGT) identified by a one‐step (fasting plasma glucose (FPG)) or a two‐step strategy (including an oral glucose tolerance test (OGTT) in subjects with impaired fasting glucose (IFG)) as recommended by the World Health Organization (WHO). Methods Twelve population‐based studies in six countries (17 512 subjects, age 30–89 years, without known diabetes, with OGTT (fasting and 2‐h plasma glucose (2‐h PG))). Age, gender, and centre‐adjusted means of CVD risk factors were compared according to the level of glucose intolerance. Results Diabetes was found in 1270 individuals and IFG or IGT in 3158. In the diabetic group 55.1% had a FPG ≥ 7.0 mmol/l (range between countries 36.2–67.0%), 20.5% were identified through the stepwise strategy (range 0–32%), while 24.4% would remain undiagnosed (FPG < 6.1 mmol/l) (range 9.0–40.0%). The two‐step strategy identified 60–91% of all newly diagnosed diabetic subjects with 5–12% of the population requiring an OGTT. Mean body mass index (BMI), blood pressure, and total cholesterol did not differ between diabetic individuals diagnosed by FPG or OGTT. The step‐wise strategy identified < 50% of the subjects with impaired glucose regulation, and the cardiovascular risk profile (BMI, blood pressure, and cholesterol) did not differ between those identified and those not identified in the screening process. Conclusions Applying an OGTT in subjects with IFG will fail to detect every fourth diabetic individual and every second individual with impaired glucose regulation. Individuals not diagnosed had a cardiovascular risk profile identical to those identified in the diagnostic process. Lower thresholds for an OGTT may be necessary in Asian populations. Diabet. Med. 19, 549–557 (2002)     

The prevalence of retinopathy in impaired glucose tolerance and recent‐onset diabetes in the Diabetes Prevention Program

Aims Retinopathy is considered the complication most closely associated with and characteristic of diabetes mellitus. Hyperglycaemia below levels diagnostic of diabetes, so called pre‐diabetes, is associated with a low prevalence of ‘diabetic’ retinopathy. However, few longitudinal studies of non‐diabetic populations have performed repeated measures of glycaemia and screened for retinopathy to determine its occurrence in the non‐diabetic population and the onset of retinopathy in new‐onset diabetic patients. We determined the prevalence of retinopathy characteristically seen in diabetes in persons with impaired glucose tolerance and in patients with new‐onset diabetes of known duration in the Diabetes Prevention Program (DPP) cohort. Methods The DPP recruited persons with elevated fasting glucose (5.3–6.9 mmol/l) and impaired glucose tolerance, and no history of diagnosed diabetes, other than gestational diabetes not persisting after pregnancy. Seven‐field, stereoscopic fundus photography was completed a mean of 3.1 years after the development of diabetes in 594 of 878 participants who had developed diabetes during the DPP, and in a random sample of 302 participants who remained non‐diabetic. Results Retinopathy consistent with diabetic retinopathy was detected in 12.6 and 7.9% of the diabetic and non‐diabetic participants, respectively (P = 0.03, comparing prevalence in the two groups). Systolic blood pressure and HbA_1c were higher at baseline in the diabetic participants who had retinopathy compared with the diabetic participants without retinopathy. Conclusions Retinopathy characteristic of diabetes is present in persons with elevated fasting glucose and impaired glucose tolerance and no known history of diabetes. The prevalence of retinopathy is significantly higher in persons who develop diabetes, even within 3 years of diagnosis.     

Validation of an algorithm combining haemoglobin A1c and fasting plasma glucose for diagnosis of diabetes mellitus in UK and Australian populations

Aim To determine whether glycated haemoglobin (HbA_1c) can be used in combination with fasting plasma glucose (FPG) for the diagnosis of diabetes in patients with impaired fasting glucose (IFG) and in a broader spectrum of patients. Methods An algorithm was derived from oral glucose tolerance test (OGTT) capillary samples in 500 consecutive UK patients with IFG by World Health Organization criteria. It was validated in a further 500 UK patients and, with venous specimens, in 1175 unselected Australian patients. Results The derivation cohort was aged 61 years (50–69 years) (median IQ range) with 52% male and 12% South Asian. Diabetes Control and Complications Trial‐aligned HbA_1c was 6.2% (5.8–6.6%) (reference interval < 6.0%) and FPG 6.7 mmol/l (6.3–7.2 mmol/l). FPG was in the diabetes range in 36% of patients, with an OGTT identifying a further 12% with diabetes. The derived algorithm, (HbA_1c ≥ 6.0% with FPG < 7.0 mmol/l) identified those patients requiring an OGTT to diagnose diabetes. When applied to the UK validation cohort, sensitivity was 97% and specificity 100%. The algorithm was equally effective in the unselected group, aged 59 years (49–68 years) and 54% male, with sensitivity 93% and specificity 100%. HbA_1c was 6.0% (5.6–6.6%) and FPG 6.0 mmol/l (5.3–6.8 mmol/l), with 26% having IFG. Use of the algorithm would reduce the number of OGTTs performed in the UK validation cohort by 33% and by 66% in the Australian patients studied. Conclusions Use of this algorithm would simplify procedures for diagnosis of diabetes and could also be used for monitoring pre‐diabetes. Validation is now required in other populations and patient groups.     

Short-term reproducibility of impaired fasting glycaemia, impaired glucose tolerance and diabetes The ADDITION study, DK

We evaluated variations in glucose measurements and the reproducibility of glucose tolerance classification in a high-risk screening setting in general practice. Screening for diabetes was performed in persons aged 40-69 years. Based on capillary fasting (FBG) and 2-h blood glucose (2 hBG) individuals with impaired fasting glycaemia (IFG), impaired glucose tolerance (IGT) and diabetes had a second test done after 14 days. Intra-individual coefficients of variation (CV) were estimated in each glucose tolerance class using the approximation CV(2)(x)=var(ln(x)). Bland-Altman plots with limits of agreement were made. In the total population, the CV(intra) was 7.9% and 13.8% for FBG and 2 hBG, respectively. Limits of agreement ranged from -1.15 to 1.67 mmol/l for FBG and from - 2.62 to 3.27 mmol/l for 2 hBG. One individual with IFG and 22.5% with IGT had diabetes at the second test, 76.1% with diabetes had this diagnosis confirmed, and about 30% with IFG and IGT had normal glucose tolerance at the second test. The expected values of repeated capillary blood glucose measurements were about+/-1 and+/-3 mmol/l for FBG and 2 hBG, respectively. Yet, 70% of high-risk prediabetic individuals were persistently classified with abnormal glucose regulation; diabetes was confirmed in 76% of the cases.     

Gestational diabetes: fasting capillary glucose as a screening test in a multi‐ethnic,high‐risk population

Aims In populations at high risk of gestational diabetes mellitus (GDM), screening every pregnant woman by an oral glucose tolerance test (OGTT) is very demanding. The aim of this study was to determine the value of the fasting capillary glucose (FCG) as a screening test for GDM. Methods FCG was measured by a plasma‐correlated glucometer in 1465 pregnant women who underwent a one‐step diagnostic 75‐g OGTT for universal screening of GDM. Results One hundred and ninety‐six (13.4%) women had GDM as defined by the criteria of the American Diabetes Association. The area under the receiver operating characteristic curve (AUC) of the FCG was 0.83 (95% confidence interval 0.80–0.86). A FCG threshold of 4.7 mmol/l (at an acceptable sensitivity of 86.0%) independently could rule‐out GDM in 731 (49.9%) women, while the FCG could rule‐in GDM (100% specificity) in 16 (1.1%) additional women; therefore, approximately half of the women would not need to continue with the cumbersome OGTT. Conclusions Screening using a FCG significantly reduces the number of OGTTs needed for the diagnosis of GDM. Wider assessment, particularly in low‐risk populations, would confirm the potential value of the FCG as a screening test for GDM.     

Rosiglitazone prevents diabetes by increasing beta-cell mass in an animal model of type 2 diabetes characterized by reduced beta-cell mass at birth

Aim:  Interventions that preserve or increase beta-cell mass may also prevent type 2 diabetes. Rosiglitazone prevents diabetes in people with high glucose levels who have impaired glucose tolerance and/or impaired fasting glucose. The effect of this drug on both glucose levels and beta-cell mass was studied in a rat model of diabetes, characterized by reduced beta-cell mass at birth with normoglycaemia, and progression to dysglycaemia with age.
Methods:  Female Wistar rats were given either saline (vehicle) or nicotine during pregnancy and lactation. Offspring of saline-exposed dams were given vehicle and offspring of nicotine-exposed dams were randomized to receive either vehicle or rosiglitazone starting at weaning. Beta-cell mass, proliferation and apoptosis were determined at birth and at 4 and 26 weeks of age. Glucose homeostasis was examined following sequential oral glucose tolerance tests (OGTT).
Results:  Rosiglitazone treatment prevented the development of dysglycaemia in nicotine-exposed animals. The ability of rosiglitazone to preserve normoglycaemia appeared to be because of its ability to increase beta-cell mass through a combination of enhanced beta-cell proliferation and decreased beta-cell apoptosis.
Conclusions:  These results suggest that if rosiglitazone administration is started prior to the onset of glucometabolic abnormalities, it prevents the onset of dysglycaemia by partially restoring beta-cell mass in animals with reduced beta-cell mass at birth.     

Comparison of the diagnostic criteria for diabetes mellitus, WHO-1985, ADA-1997 and WHO-1999 in the adult population of Asturias (Spain).

AIMS: To estimate the prevalence of diabetes mellitus with three diagnostic criteria (WHO-1985 and 1999 and ADA-1997), evaluate their concordance and analyse the sensitivity and specificity of the different screening strategies for diabetes. METHODS: A cross-sectional population study with two-step sampling. One thousand and 34 people were selected randomly. A 75-g oral glucose tolerance test (OGTT) was performed and venous blood samples were obtained fasting and at 2 h. RESULTS: The prevalence of known Type 2 diabetes mellitus (DM-2) is 4%[95% confidence interval (CI) 2.8, 5.1]. By WHO-1985 criteria the prevalence of unknown DM-2 is 5.9% (4.5, 7.4); by ADA-1997 criteria 3.5% (2.5, 4.6) and by WHO-1999 criteria 7.3% (5.8, 8.8). Diagnostic overlap and statistical concordance (coefficient K) are WHO-1985/ADA-1997 29.3%, K=0.42; WHO-1985/WHO-1999 80%, K=0.88; ADA-1997/WHO-1999 48%, K=0.63. If only fasting glucose was used (following ADA-1997), 36.3% of those with diabetes (2-h glucose > or =11.1 mmol/l) would be diagnosed. If OGTT was performed (i) in those with a fasting glucose between 6.1 mmol/l and 6.9 mmol/l (9.8% of the population) we would diagnose 66.6%, and (ii) in all those between 5.7 mmol/l and 6.9 mmol/l (18.9% of the population) 81.8% would be diagnosed. CONCLUSIONS: The ADA criteria decrease the prevalence of DM in the adult population of Asturias by 2.4% and concordance with the classical criteria (WHO-1985) was only 29.3%. Using fasting glucose only (ADA-1997) diagnoses 36.3% of those with diabetes. The recent recommendations of the WHO-1999 increases this to 66.6%. To improve the diagnostic strategy for diabetes and detect up to 81.8% of patients, we propose the use of OGTT for all those with a fasting glucose between 5.7 mmol/l and 6.9 mmol/l.     

Screening for diabetes mellitus--a two-step approach in individuals with impaired fasting glucose improves detection of those at risk of complications.

AIMS: To compare the new American Diabetes Association (ADA) fasting plasma glucose (FPG) criteria to the 1985 World Health Organization (WHO) 2-h post glucose (2hPG) criteria when used for screening of those with no prior history of diabetes mellitus. METHODS: The study included 3,407 subjects without a history of diabetes in whom both FPG and 2hPG were available from the 1992 Singapore National Health Survey. The agreement (kappa) between FPG and 2hPG for the diagnosis of DM was assessed. The optimal cut-off of FPG for the detection of individuals with 2hPG > or = 11.1 mmol/l was determined by receiver-operating characteristics analysis. RESULTS: The prevalence of diabetes diagnosed by FPG alone was 7.3% compared to 8.4% diagnosed by 2hPG. The prevalence of impaired fasting glucose was 8.0%. FPG and 2hPG showed moderate agreement (kappa = 0.646, 95% confidence interval 0.584-0.708). Age, ethnic group and obesity did not affect the degree of agreement. Of those with 2hPG > or = 11.1 mmol/l, 40.8% had FPG in the non-diabetic range while 24.8% of those with FG > or = 7.0 mmol/l had 2hPG in the non-diabetic range. The optimal FPG for the detection of 2hPG > or =11.1 mmol/l was 6.1 mmol/l. Oral glucose tolerance tests (OGTT) in those with 6.0 mmol/ < FPG < 7.0 mmol/l resulted in the diagnosis of diabetes in 90.7% of individuals at risk of microvascular complications. CONCLUSIONS: FPG provides a simple screening test for diabetes, which shows moderate agreement with the 2hPG. A two-step strategy of OGTT in those with impaired fasting glucose improves the detection of at-risk individuals. However, diabetes should not be diagnosed on a single test. The test should be repeated on another day if an individual tests positive for diabetes.     

A postnatal fasting plasma glucose is useful in determining which women with gestational diabetes should undergo a postnatal oral glucose tolerance test.

AIMS: It is recommended that women with gestational diabetes (GDM) should have a 6-week postnatal oral glucose tolerance test (OGTT). As this test may be unpleasant, time-consuming and has resource implications, we evaluated whether the 6-week postnatal fasting glucose could be used to determine which women should undergo an OGTT. METHODS: All women with GDM, diagnosed according to the World Health Organization criteria, who were delivered at the Princess Anne Hospital, Southampton between May 2000 and May 2002, were recommended to have an OGTT. The results of the fasting plasma glucose concentration were assessed in relation to the 2-h glucose value. RESULTS: One-hundred and fifty-two women with GDM were delivered. Thirty (19.7%) women refused an OGTT or failed to attend. In the 122 OGTTs, three (2.4%; 95% confidence interval 0.8, 7) women had diabetes, three had impaired glucose tolerance and four had impaired fasting glycaemia. No woman with a normal test had fasting glucose of > or =6.0 mmol/l. Fasting glucose was correlated with the 2-h glucose (r=0.62, P<0.0001). Only 10 (8.1%) of the OGTTs would have been performed if only women with fasting glucose of > or =6.0 mmol/l underwent the test. The sensitivity and specificity of this approach for the diagnosis of postnatal diabetes is 100% and 94%, respectively. Linear regression methods indicate that it would miss fewer than three in 10 000 cases. CONCLUSIONS: In our population, a 6-week postnatal fasting plasma glucose is useful in determining which women with gestational diabetes should undergo an OGTT. Consequently we now perform OGTT only in women whose postnatal fasting plasma glucose is > or =6.0 mmol/l.     

Irish diabetes detection programme in general practice.

OBJECTIVES: To assess the prevalence of undiagnosed diabetes, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) in patients over the age of 40 years attending their general practitioner (GP) in Ireland, through opportunistic screening, using a three-step screening tool involving self-determined high-risk groups, random venous plasma glucose (RVPG) measurement and oral glucose tolerance tests. DESIGN: In participating general practices, 100 consecutive patients > 40 years, completed a screening questionnaire relating to diabetes-related symptoms and risk factors. Patients with previously diagnosed diabetes were not excluded from the study and the screening instrument included a question about known diabetes. Patients without known diabetes mellitus (DM) and with at least two risk factors and/or symptoms underwent a RVPG test. Those with an RVPG above 5.5 mmol/l underwent an oral glucose tolerance test. RESULTS: Forty-one practices returned 3821 questionnaires. The prevalence of Type 2 diabetes mellitus in the study population was 9.2% (353), of whom 23.5% (83) were previously undiagnosed. DM was detected on the basis of an RVPG >11.1 mmol/l in 0.8% (32) of the studied population. DM was detected on the basis of the oral glucose tolerance test in 1.3% (51) of the population. One per cent (39) had a fasting plasma glucose (FPG) > or = 7.0 mmol/l, 0.6% (24) had a 2-h >11.0 mmol/l and 0.3% (12) had both. Diabetes would not have been detected in 12 people had the 2-h test been omitted. The prevalence rate for IFG and/or IGT was 3.9% (148). Of the 103 patients with IGT, 83 (81%) would have been missed had the GTT been omitted. CONCLUSION: Opportunistic diabetes screening in general practice using a screening questionnaire followed by RVPG testing and GTT for those above 5.5 mmol/l is feasible, with a high participation rate. The use of GTTs rather than fasting glucose testing alone improves patient identification, in particular those with IGT who are at higher cardiovascular risk.     

A screening procedure for diabetes in pregnancy

A screening system for detection of diabetes in pregnancy was carried out in a geographically well-defined unselected population of 2 457 pregnant women all living in the community of Copenhagen. The screening was based on clinical criteria for potential diabetes consisting of previous delivery of a large baby, a family history of diabetes and obesity combined with examination of glucosuria and determination of the fasting blood glucose concentration. It was possible to follow up 95% of all pregnancies. One hundred and ninety women had a positive screening determination and among these women, 24 (1%) were found to have diabetes in pregnancy. It was established that a fasting blood glucose concentration of 4.1 mmol/l was the ideal cut-off point for referring potential diabetics to an oral glucose tolerance test (OGTT). The screening procedure is easy to administer and acceptable for the pregnant woman. The screening OGTT should be performed in the second or third trimester as only one woman had diabetes detected in the first trimester in this study.     

Increasing trend in the prevalence of Type 2 diabetes and pre‐diabetes in the Chinese rural and urban population in Qingdao,China

Aims To determine the secular trend of prevalence of Type 2 diabetes and pre‐diabetes in a Chinese population from 2001 to 2006. Methods Two consecutive population‐based surveys for diabetes were conducted in a randomly selected population aged 35–74 years and living in Qingdao, China in 2001–2002 (n = 10854) and 2006 (n = 4416). All participants underwent standardized 2‐h 75‐g oral glucose tolerance tests (OGTTs), along with fasting capillary plasma glucose (FCG) tests in 2006. One urban community underwent OGTTs directly in 2002 (n = 1815), while a two‐step screening strategy using FCG as a first‐line screening test followed by OGTTs was used in 9039 individuals in 2001. Diabetes and pre‐diabetes was defined according to the 2006 World Health Organization/International Diabetes Federation criteria. Results Based on the results of direct OGTTs, the age‐standardized prevalence of diabetes and pre‐diabetes in urban areas was 12.2 and 15.4% in 2002, whereas the prevalences were 18.8 and 28.7% in urban areas and 14.1 and 20.2% in rural areas in 2006 (P < 0.001, in urban areas). Using the two‐step screening strategy, the prevalence of diabetes in 2001 was 10.1% in urban and 7.7% in rural areas and 13.8% in urban and 12.2% in rural areas in 2006 (P < 0.001). Based on the data of the 2006 survey, the two‐step screening strategy missed 30.2% of diabetes cases when compared with the number defined by the direct OGTT approach. Conclusions Qingdao has experienced a marked increase in the prevalence of diabetes and pre‐diabetes in the past 5 years. Intervention to prevent a further increase in the prevalence of diabetes is urgently required.     

Fasting plasma glucose and glycated haemoglobin in the screening of diabetes and impaired glucose tolerance

Abstract. The use of fasting plasma glucose (FPG) only has been proposed for the screening and diagnosis of diabetes, but its sensitivity has been reported to be unsatisfactory. The use of HbA_1C, alone or combined with FPG, has been suggested for the screening of diabetes and impaired glucose tolerance (IGT). In a sample of 1215 adult subjects without previously known diabetes, we assessed the sensitivity and specificity of FPG and HbA_1C in diagnosing diabetes and IGT, determined by oral glucose tolerance test (OGTT). All lean diabetic patients, and 85% of overweight and obese diabetic individuals, had FPG 7 mmol/l. FPG >6.1 mmol/l had a sensitivity of 98.8% and a specificity of 32.9%; HbA_1C had a lower specificity and sensitivity for the screening of diabetes. A screening strategy for diabetes based on FPG, with OGTT in all overweight subjects with FPG >6.1 mmol/l, is suggested. Neither FPG nor HbA_1C is effective in the screening of IGT; although combined FPG and HbA_1C could be useful for case finding, screening for IGT with OGTT is advisable in all subjects at high risk.     

Comparison of the results between two diagnostic criteria by ADA and WHO among subjects with FPG 5.6-7.8 mmol/l in Kin-Hu and Kin-Chen, Kinmen, 1991-94.

The objective of this study was to compare the results between two diagnostic criteria by ADA (1997) and WHO (1985) among those with fasting plasma glucose (FPG) level 5.6-7.8 mmol/l from a community-based survey in Kin-Hu and Kin-Chen, Kinmen conducted in 1991-94. According to official household registry, 10,797 residents aged over 30 were eligible for screening. 7580 had completed FPG screening and 1855 with FPG 5.6-7.8 mmol/l were invited to receive a 75-g oral glucose tolerance test (OGTT). 78.5% (1456/1855) had completed OGTT. The prevalence of impaired fasting glucose (IFG, by ADA) was 15.7%; the prevalence of impaired glucose tolerance (IGT, by WHO) was 22.7%; the prevalence of undiagnosed diabetes was 7.4% by ADA criteria and 10.9% by WHO criteria. It should be noticed that, among subjects with FPG 5.6-7.8 mmol/l, 50.3% of individuals with undiagnosed diabetes and 67.6% of individuals with IGT by WHO criteria would be missed by ADA criteria. Based on the above findings, the two-step screening strategy using FPG as the first line screening and OGTT for high-risk group (FPG 5.6-7.8 mmol/l) only was recommended in epidemiological study and case finding in consideration of feasibility and validity.     

Prevalence and projections of diabetes and pre‐diabetes in adults in Sri Lanka—Sri Lanka Diabetes,Cardiovascular Study (SLDCS)

Aims To determine the prevalence of diabetes mellitus and pre‐diabetes (impaired fasting glucose and impaired glucose tolerance) in adults in Sri Lanka. Projections for the year 2030 and factors associated with diabetes and pre‐diabetes are also presented. Methods This cross‐sectional study was conducted between 2005 and 2006. A nationally representative sample of 5000 adults aged ≥ 18 years was selected by a multi‐stage random cluster sampling technique. Fasting plasma glucose was tested in all participants and a 75‐g oral glucose tolerance test was performed in non‐diabetic subjects. Prevalence was estimated for those > 20 years of age. Results Response rate was 91% (n = 4532), males 40%, age 46.1 ± 15.1 years (mean ± standard deviation). The age–sex standardized prevalence (95% confidence interval) of diabetes for Sri Lankans aged ≥ 20 years was 10.3% (9.4–11.2%) [males 9.8% (8.4–11.2%), females 10.9% (9.7–12.1%), P = 0.129). Thirty‐six per cent (31.9–40.1%) of all diabetic subjects were previously undiagnosed. Diabetes prevalence was higher in the urban population compared with rural [16.4% (13.8–19.0%) vs. 8.7% (7.8–9.6%); P < 0.001]. The prevalence of overall, urban and rural pre‐diabetes was 11.5% (10.5–12.5%), 13.6% (11.2–16.0%) and 11.0% (10.0–12.0%), respectively. Overall, 21.8% (20.5–23.1%) had some form of dysglycaemia. The projected diabetes prevalence for the year 2030 is 13.9%. Those with diabetes and pre‐diabetes compared with normal glucose tolerance were older, physically inactive, frequently lived in urban areas and had a family history of diabetes. They had higher body mass index, waist circumference, waist–hip ratio, systolic/diastolic blood pressure, low‐density lipoprotein cholesterol and triglycerides. Insulin was prescribed to 4.4% (2.7–6.1%) of all diabetic subjects. Conclusions One in five adults in Sri Lanka has either diabetes or pre‐diabetes and one‐third of those with diabetes are undiagnosed.     

The abbreviated glucose tolerance test in screening for diabetes: the Islington Diabetes Survey

The World Health Organization has recommended a single 2-h post-glucose load blood glucose level as a screening test for diabetes mellitus in epidemiological surveys. We have assessed its characteristics, when compared with a full supervised glucose tolerance test (OGTT), in estimating prevalence, and in diagnosing diabetes in the individual patient. A stratified sample of 223 of 1040 subjects who had participated in a diabetic survey that utilized a single capillary 2-h blood glucose estimation as a screening test were recalled for formal glucose tolerance testing. The numbers of subjects with diabetes at screening and at recall were similar (14/212, 6.6%; 13/216, 6.0%) but only 9 subjects were so classified on both occasions. Thirty-five subjects (16.5%) were suspected of having impaired glucose tolerance (IGT) at screening, and 52 (24.1%) at recall. There was substantial reclassification from screening IGT, with 3/35 worsening to diabetes, and 10/35 returning to normal. Capillary 2-h glucose levels gave an accurate assessment of the prevalence of diabetes but underestimated that of IGT. On the full OGTT, little difference in classification was found when the values of fasting and 1-h blood glucose were used in addition to those of the 2-h blood glucose used alone. The 2-h glucose had a within-subject coefficient of variation of 32.4% which produced substantial reclassification of subjects with levels close to the diagnostic levels for diabetes, and this implies that such individuals should not be classified as having diabetes on the basis of a single glucose tolerance test.(ABSTRACT TRUNCATED AT 250 WORDS)