Opportunistic screening for diabetes in routine clinical practice

OBJECTIVE: Since 1997, the American Diabetes Association has recommended that nondiabetic individuals >/=45 years of age be screened for diabetes at least every 3 years. We sought to characterize the frequency, methods, and results of diabetes screening in routine clinical practice. RESEARCH DESIGN AND METHODS: We studied opportunistic screening in nondiabetic members of a health maintenance organization >/=45 years of age who were assigned to a large, integrated, academic health care delivery system. Screening was defined as the first glucose, HbA(1c), or oral glucose tolerance test (OGTT) performed between 1 January 1998 and 31 December 2000. Chart review was performed to determine the prevalence of diabetes risk factors and to describe follow-up. RESULTS: Of 8,286 nondiabetic patients >/=45 years of age, 69% (n = 5,752) were screened. The frequency of screening was greater in patients with one or more primary care visits and increased with age. Women were more likely to be screened than men, and patients with at least one diabetes risk factor were more likely to be screened than those without risk factors. Random plasma glucose was the most common screening test (95%). Four percent (n = 202) of those screened had abnormal results. Only 38% (n = 77) of those with abnormal results received appropriate follow-up, and 17% (n = 35) were diagnosed with diabetes within 6 months of screening. The yield of screening was very low (0.6%, 35 of 5,752). CONCLUSIONS: Despite frequent screening and appropriate targeting of high-risk patients, follow-up of patients with abnormal results is uncommon and the yield of screening is low. Interventions are needed to help physicians recognize and provide appropriate follow-up for patients with potentially abnormal random glucose levels.     

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.     

Peptide hormones and risk for future cardiovascular events among prediabetics: a 20-year follow-up in the OPERA study

Abstract

Background: Prediabetes has proven to have many unfavourable impacts on the cardiovascular system.

Methods: The OPERA (Oulu Project Elucidating Risk of Atherosclerosis) study included 1045 middle-aged subjects followed from the years 1990–1993 to 2014. The focus was on peptide hormones.

Results: Plasma resistin levels were higher among prediabetics (p?=?.001), particularly impaired glucose tolerance (IGT) (p?<?.001), but not impaired fasting glucose (IFG) patients than among normal glucose tolerance (NGT) or diabetes groups. Diabetics showed lower resistin levels than IGT subjects (p?<?.001). IGT or diabetes groups showed lower adiponectin and higher leptin levels compared to the NGT group (p?<?.001). The IFG group had the highest blood pressure and left ventricular mass index, even higher than the diabetic group. Diabetics had the highest, prediabetics (IFG?+?IGT) intermediate and NGT the lowest risk for CVD events during follow-up (p?<?.001). Among prediabetics, high plasma ghrelin was an independent predictor of CVD events (p?<?.05) in the Cox regression analysis although it did not significantly improve either classification or discrimination of the patients.

Conclusions: Among glucose tolerance groups, patients with IGT had the highest resistin, but equally high leptin and low adiponectin levels as diabetics. Among prediabetics, ghrelin seems to predict independently cardiovascular events in the long term.

• KEY MESSAGE

• Among glucose tolerance groups, patients with IGT had the highest resistin, but equally high leptin and low adiponectin levels as diabetics.

• Among prediabetics, ghrelin seems to predict independently cardiovascular events in the long term.

     

Community-based screening for diabetes in Michigan

OBJECTIVE: To describe and evaluate a community-based diabetes screening program supported by the Michigan Department of Community Health. RESEARCH DESIGN AND METHODS: Between 1 June 1999 and 31 December 1999, community screening for diabetes was conducted by voluntary organizations using a standard protocol, American Diabetes Association (ADA) questionnaires, and ADA capillary plasma glucose criteria. RESULTS: A total of 3506 individuals were screened, 14% of whom did not meet criteria for screening. Of the 3031 individuals appropriately screened, 57% were classified as being at high risk based on the ADA questionnaire and 5% had positive screening tests based on ADA capillary plasma glucose criteria. Despite systematic follow-up, the screening program's yield of individuals with undiagnosed diabetes was <1%. CONCLUSIONS: Community screening for diabetes conducted according to ADA recommendations was extremely inefficient at identifying individuals with undiagnosed diabetes. The ADA diabetes screening questionnaire resulted in many false positive tests, and the ADA criteria for positive plasma glucose tests likely missed a substantial portion of individuals with undiagnosed diabetes. Relying on biochemical tests such as random plasma glucose, changing the criteria for a positive plasma glucose test, targeting racial and ethnic minority groups, and targeting medically underserved individuals might improve the yield of community-based diabetes screening.     

Efficient cutoff points for three screening tests for detecting undiagnosed diabetes and pre-diabetes: an economic analysis

OBJECTIVE: Opportunistic screening for undiagnosed type 2 diabetes and pre-diabetes (either impaired glucose tolerance or impaired fasting glucose) is recommended by the American Diabetes Association. The aim of this study was to determine efficient cutoff points for three screening tests for detecting undiagnosed diabetes alone or both undiagnosed diabetes and pre-diabetes. RESEARCH DESIGN AND METHODS: We estimated the number of individuals with undiagnosed diabetes alone or with both undiagnosed diabetes and pre-diabetes that could be detected by using different cutoff points for each screening test as the product of the prevalence of each condition, the sensitivity of the tests at each cutoff point for identifying each condition, and the number of individuals who would be eligible for screening in the U.S. We estimated the total cost of opportunistic screening by multiplying the cost for screening one person by the number of individuals screened. RESULTS: The most efficient cutoff points for both detecting pre-diabetes and undiagnosed diabetes (100 mg/dl for the fasting plasma glucose test, 5.0% for the HbA(1c) test, and 100 mg/dl for the random capillary blood glucose test) were less than those for detecting undiagnosed diabetes alone (110 mg/dl for the fasting plasma glucose test, 5.7% for the HbA(1c) test, and 120 mg/dl for the random capillary blood glucose test). CONCLUSIONS: A lower cutoff value should be used when screening for pre-diabetes and undiagnosed diabetes together than when screening for undiagnosed diabetes alone.     

Presence of diabetes risk factors in a large U.S. eighth-grade cohort

OBJECTIVE: The study was conducted in 12 middle schools to determine the prevalence of diabetes, pre-diabetes, and diabetes risk factors in eighth-grade students who were predominantly minority and evaluate the feasibility of collecting physical and laboratory data in schools. RESEARCH DESIGN AND METHODS: Anthropometric measurements and fasting and 2-h post-glucose load blood draws were obtained from approximately 1,740 eighth-grade students. RESULTS: Mean recruitment rate was 50% per school, 49% had BMI > or = 85th percentile, 40.5% had fasting glucose > or = 100 mg/dl, 0.4% had fasting glucose > or = 126 mg/dl, and 2.0% had 2-h glucose > or = 140 mg/dl and 0.1% > or = 200 mg/dl. Mean fasting insulin value was 30.1 microU/ml, 36.2% had fasting insulin > or = 30 microU/ml, and 2-h mean insulin was 102.1 microU/ml. Fasting and 2-h glucose and insulin values increased across BMI percentiles, and fasting glucose was highest in Hispanic and Native American students. CONCLUSIONS: There was a high prevalence of risk factors for diabetes, including impaired fasting glucose (> or =100 mg/dl), hyperinsulinism suggestive of insulin resistance (fasting insulin > or = 30 microU/ml), and BMI > or = 85th percentile. These data suggest that middle schools are appropriate targets for population-based efforts to decrease overweight and diabetes risk.     

The prevalence of diabetes and impaired glucose tolerance in Sivas, Central Anatolia, Turkey

OBJECTIVE: The aim of this study was to determine type 2 diabetes, impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) prevalence in Sivas, Turkey. RESEARCH DESIGN AND METHODS: This cross-sectional study was conducted in the city center of Sivas. The study population of 771 subjects was selected by the cluster sampling method from 115,998 individuals aged > or =30 years. Participants with fasting venous plasma glucose concentrations <100 mg/dl were classified as "normal." Diabetes was diagnosed in participants if they had fasting blood glucose levels > or =126 mg/dl. An oral glucose tolerance test (OGTT) was performed in subjects with fasting blood glucose levels > or =100 mg/dl and <126 mg/dl. RESULTS: According to the fasting blood glucose levels of the 771 subjects, 44 (5.7%) had diabetes. OGTTs were performed in 80 (10.4%) subjects. According to OGTT results, there were 5 subjects with diabetes, 20 subjects with IGT (2.6%), and 55 subjects with IFG (7.1%). The combined prevalence of IFG and IGT was 9.7%. After OGTT, the total number of diabetic subjects was determined to be 49 (6.4%). Twenty-four (3.1%) of the subjects had a previous diagnosis of diabetes. Multivariate analyses showed that age, sex, hypertension, cigarette smoking, obesity, and family history of diabetes were risk factors for type 2 diabetes (P < 0.05). CONCLUSIONS: Diabetes incidence increases with changes in dietary habits and lifestyle. Education is particularly important for public health, as the community may then have required knowledge about the disease and its risk factors.     

Use of the diabetes risk score for opportunistic screening of undiagnosed diabetes and impaired glucose tolerance: the IGLOO (Impaired Glucose Tolerance and Long-Term Outcomes Observational) study

OBJECTIVE: To evaluate an opportunistic screening strategy addressed to individuals with one or more cardiovascular risk factor, based on the Diabetes Risk Score (DRS) as the initial instrument, for the identification of individuals with type 2 diabetes or impaired glucose tolerance (IGT). RESEARCH DESIGN AND METHODS: The DRS, a simple self-administered questionnaire, was completed by individuals identified by general practitioners and presenting with one or more cardiovascular risk factor. All patients underwent a 2-h oral glucose tolerance test (OGTT). The optimal DRS cutoff was calculated by applying the receiver-operating characteristic curve. RESULTS: Overall, 1,377 individuals aged between 55 and 75 years received an OGTT and completed the DRS. Mean DRS values showed a marked variation according to glucose metabolism categories, as follows: 8.7 +/- 3.0 in normoglycemic individuals, 9.5 +/- 3.1 in individuals with impaired fasting glucose, 9.9 +/- 3.3 in individuals with IGT, and 12.0 +/- 3.5 in individuals with type 2 diabetes. The receiver-operating characteristic curve showed that, with a cutoff of 9, the sensitivity of DRS in detecting individuals with glucose abnormalities (type 2 diabetes or IGT) was 77% and the specificity 45%. The use of the DRS as an initial screening instrument, followed by the measurement of fasting blood glucose in individuals with a score > or =9 and by the OGTT in individuals with a fasting blood glucose between 5.6 and 6.9 mmol/l, would lead to the identification of 83% of the case subjects with type 2 diabetes and 57% of the case subjects with IGT, at a cost of an OGTT in 38% of the sample and a fasting blood glucose in 64%. CONCLUSIONS: The DRS can represent a valid inexpensive instrument for opportunistic screening and a useful alternative to indiscriminate fasting blood glucose measurement, not readily available in general practice.     

Gestational diabetes mellitus in women of single gravidity in Tianjin City, China

OBJECTIVE: The aim of this study was to investigate the prevalence of gestational diabetes mellitus (GDM) and risk factors for the development of GDM in pregnant women in Tianjin, China, where the prevalence of GDM is still unknown. STUDY DESIGN AND METHODS: A total of 9,471 pregnant women living in the six urban districts of Tianjin, China, took part in the initial screening between December 1998 and December 1999. The screening test consisted of a 50-g 1-h glucose test. Women with a reading > or =7.8 mmol/l at the initial screening were invited to undergo a 75-g 2-h oral glucose tolerance test (OGTT). GDM was confirmed using the World Health Organization's diagnostic criteria. RESULTS: At the initial screening test, 888 women had a glucose reading of > or =7.8 mmol/l. A total of 701 (79%) women took a subsequent OGTT. Of these, 174 women were confirmed to have GDM (154 with impaired glucose tolerance [IGT] and 20 with diabetes). The prevalence of GDM was 2.31% (2.03% for IGT and 0.28% for diabetes), adjusting for serum glucose levels at the initial screening test. Independent predictors for GDM were maternal age, stature, prepregnancy BMI, weight gain in pregnancy before screening, diabetes in first-degree relatives, and habitual cigarette smoking during pregnancy. Women who smoked or had a short stature are more likely to develop GDM than their counterparts. CONCLUSIONS: The prevalence of GDM in pregnant women in the city of Tianjin, China, was 2.31%. Short stature and smoking in pregnancy were additional risk factors for GDM.     

Renal impairment in elderly patients with hypertension and diabetes

We investigated the prevalence of renal impairment in individuals with known hypertension or diabetes aged 50--75 years in two South London General PRACTICES: We initially interrogated the practice and hospital biochemistry databases for each individual's most recent serum creatinine. Individuals with no result recorded in the previous year were then invited for screening: 189/365 (51.8%) attended. Data were collected on 821 of a total potential population of 997. Taking a serum creatinine of 120 mmol/l as the upper limit of normal, the overall prevalence of renal disease in this population was 8.4%: 6.1% in the hypertensives, 12.6% in the diabetics and 16.9% in those with both. Significant proteinuria (> or =2+) was present in 3.9% of the total population: 2.2% of hypertensives, 8.3% of diabetics and 3.9% of those with both. At screening, 44.5% of individuals had inadequately controlled blood pressure. Renal impairment is common in this population at high risk of renal disease. Screening for renal disease in this population is simple, safe and gives a high yield of positive results.     

Outcomes of screening for diabetes in high-risk Hong Kong Chinese subjects

OBJECTIVE: To examine the significance of individual risk factors on the development of diabetes in subjects who underwent screening for diabetes. RESEARCH DESIGN AND METHODS: A total of 1,649 Chinese subjects underwent screening for diabetes. They were asymptomatic but had known risk factors for diabetes, including a positive family history of diabetes, a past history of gestational diabetes, obesity, hypertension, and/or dyslipidemia. Another 799 age-matched subjects from the community who had no risk factors for diabetes were used as the comparison group. RESULTS: Of the 1,649 subjects who underwent screening, 241 (14.6%) had diabetes. In these subjects, 989 (60.0%) had 1 risk factor, 502 (30.4%) had 2 risk factors, 141 (8.6%) had 3 risk factors, and 17 (1.0%) had 4 or 5 risk factors for diabetes. Of the 799 control subjects, 29 (3.6%) had diabetes. Compared with the comparison group, the odds ratio (95% CI) of having diabetes after adjustment for age was 5.2 (3.5-7.7) in the 1,649 subjects with known risk factors. The odds ratio of having diabetes increased from 3.7 in subjects with 1 risk factor to 28.4 in subjects with 4 or 5 risk factors. CONCLUSIONS: In men, age, BMI, family history of diabetes, and dyslipidemia, and in women, age, BMI, hypertension, dyslipidemia, total cholesterol, and history of gestational diabetes are associated with increased odds of developing diabetes. These risk factors have additive effects on the odds of having diabetes. Early and regular screening for diabetes and other cardiovascular risk factors is essential in these high-risk individuals.     

Screening for impaired glucose tolerance. Results from a population-based study in 21,057 individuals

OBJECTIVE: To study the distribution of fasting plasma glucose and impaired glucose tolerance (IGT) in a large general population and explore their possible implications for large-scale screening. The study focuses especially on the relation to age, obesity, and heredity background of diabetes. RESEARCH DESIGN AND METHODS: A total of 21,057 men and women aged 30-60 years were used for this cross-sectional study. Individuals with known diabetes and individuals with a fasting plasma glucose > or = 7 mmol/l were excluded. A physical examination, including blood sampling and an oral glucose tolerance test, was conducted. RESULTS: The relative risk for IGT increased more than fourfold among obese subjects compared with normal-weight subjects, yet only 25% of IGT subjects were obese. Similarly, IGT subjects more frequently reported having first-degree relatives with diabetes than did subjects with normal glucose tolerance. Nonetheless, > 70% of IGT subjects reported no heredity background of diabetes. Subjects with IGT showed higher mean values of BMI, blood pressure, and triglycerides. Only 13% of the men and 19% of the women having impaired fasting glucose (IFG) fulfilled the criteria of IGT. CONCLUSIONS: The present study shows that a high-risk screening strategy for IGT targeted solely toward subjects with obesity and/or heredity background of diabetes will fail to detect the majority of subjects with IGT in the general population. The new concept of IFG may not replace the concept of IGT as a risk marker for worsening to diabetes.     

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

OBJECTIVE: To develop and validate an empirical equation to screen for diabetes. RESEARCH DESIGN AND METHODS: A predictive equation was developed using multiple logistic regression analysis and data collected from 1,032 Egyptian subjects with no history of diabetes. The equation incorporated age, sex, BMI, postprandial time (self-reported number of hours since last food or drink other than water), and random capillary plasma glucose as independent covariates for prediction of undiagnosed diabetes. These covariates were based on a fasting plasma glucose level >/=126 mg/dl and/or a plasma glucose level 2 h after a 75-g oral glucose load >/=200 mg/dl. The equation was validated using data collected from an independent sample of 1,065 American subjects. Its performance was also compared with that of recommended and proposed static plasma glucose cut points for diabetes screening. RESULTS: The predictive equation was calculated with the following logistic regression parameters: P = 1/(1 - e(-x)), where x = -10.0382 + [0.0331 (age in years) + 0.0308 (random plasma glucose in mg/dl) + 0.2500 (postprandial time assessed as 0 to >/=8 h) + 0.5620 (if female) + 0.0346 (BMI)]. The cut point for the prediction of previously undiagnosed diabetes was defined as a probability value >/=0.20. The equation's sensitivity was 65%, specificity 96%, and positive predictive value (PPV) 67%. When applied to a new sample, the equation's sensitivity was 62%, specificity 96%, and PPV 63%. CONCLUSIONS: This multivariate logistic equation improves on currently recommended methods of screening for undiagnosed diabetes and can be easily implemented in a inexpensive handheld programmable calculator to predict previously undiagnosed diabetes.     

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.     

Joint distribution of non-HDL and LDL cholesterol and coronary heart disease risk prediction among individuals with and without diabetes

OBJECTIVE: To assess coronary heart disease (CHD) risk within levels of the joint distribution of non-HDL and LDL cholesterol among individuals with and without diabetes. RESEARCH DESIGN AND METHODS: We used four publicly available data sets for this pooled post hoc analysis and confined the eligible subjects to white individuals aged > or = 30 years and free of CHD at baseline (12,660 men and 6,721 women). Diabetes status was defined as either "reported by physician-diagnosed and on medication" or having a fasting glucose level > or = 126 mg/dl at the baseline examination. The primary end point was CHD death. Within diabetes categories, risk was assessed based on lipid levels (in mg/dl): non-HDL <130 and LDL <100 (group 1); non-HDL <130 and LDL > or = 100 (group 2); non-HDL > or = 130 and LDL <100 (group 3); and non-HDL > or = 130 and LDL > or = 100 (group 4). Group 1 within those without diabetes was the overall reference group. RESULTS: Of the subjects studied, approximately 6% of men and 4% of women were defined as having diabetes. A total of 773 CHD deaths occurred during the average 13 years of follow-up time. A Cox proportional hazard model was used to estimate the relative risk (RR) of CHD death. Those with diabetes had a 200% higher RR than those without diabetes. In a multivariate model, CHD risk in those with diabetes did not increase with increasing LDL, whereas it did increase with increasing non-HDL: RR (95% confidence interval) for group 1: 5.7 (2.0-16.8); group 2: 5.7 (1.6-20.7); group 3: 7.2 (2.6-19.8); and group 4: 7.1 (3.7-13.6). CONCLUSIONS: Non-HDL is a stronger predictor of CHD death among those with diabetes than LDL and should be given more consideration in the clinical approach to risk reduction among diabetic patients.     

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.     

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.     

Sensory function and albumin excretion according to diagnostic criteria for diabetes

OBJECTIVE: The purpose of this study was to examine sensory function and albumin excretion according to categories of glucose tolerance in individuals undergoing screening for diabetes. RESEARCH DESIGN AND METHODS: Sensory function and albumin excretion measurements were obtained in 636 individuals at the time of screening for diabetes according to American Diabetes Association glucose tolerance criteria. Sensory thresholds were measured by forced-choice techniques. Albumin-to-creatinine ratios were calculated from spot urine samples. RESULTS: Of 90 individuals whose glucose levels were in the range for diabetes, 65 had fasting glucose values >or=126 mg/dl, whereas 25 had 2-h glucose values >or=200 mg/dl, with fasting glucose values <126 mg/dl. In covariance analyses, those with fasting glucose levels >or=126 mg/dl had higher vibration (P < 0.01) and thermal (P < 0.05 for cool and warm) thresholds than those with normal glucose tolerance. This pattern was also evident for albumin-to-creatinine ratios (P < 0.001). In contrast, those with 2-h glucose values >or=200 mg/dl and fasting glucose values <126 mg/dl had sensory threshold and albumin-to-creatinine ratio values similar to those of the normal group. Individuals with fasting glucose levels >or=126 mg/dl had higher vibration threshold and albumin-to-creatinine ratio values (<0.05 and <0.01, respectively) than those with levels <126 mg/dl. CONCLUSIONS: Sensory threshold and albumin excretion values already tend to be greater than normal at screening in individuals with fasting glucose levels >or=126 mg/dl, but not in those with levels <126 mg/dl. A reliance on fasting glucose levels >or=126 mg/dl for screening might not be sufficient for early intervention and the optimal prevention of diabetes complications.     

The prevalence and management of diabetes in Thai adults: the international collaborative study of cardiovascular disease in Asia

OBJECTIVE: The aim of this study was to determine in Thai adults aged >or=35 years the prevalence and management of diabetes and the associations of diabetes with cardiovascular risk factors. RESEARCH DESIGN AND METHODS: The International Collaborative Study of Cardiovascular Disease in Asia was a complex sample survey. Data from a structured questionnaire, brief physical examination, and blood sample were collected from 5,105 individuals aged >or=35 years (response rate 68%). Population estimates were calculated by applying sampling weights derived from the 2000 Thai census. RESULTS: The estimated national prevalence of diabetes in Thai adults was 9.6% (2.4 million people), which included 4.8% previously diagnosed and 4.8% newly diagnosed. The prevalence of impaired fasting glucose was 5.4% (1.4 million people). Diagnosed diabetes, undiagnosed diabetes, and impaired fasting glucose were associated with greater age, BMI, waist-to-hip ratio, systolic blood pressure, total cholesterol, and serum creatinine levels. The majority of individuals with diagnosed diabetes had received dietary or other behavioral advice, and 82% were taking oral hypoglycemic therapy. Blood pressure-lowering therapy was provided to 67% of diagnosed diabetic patients with concomitant hypertension. CONCLUSIONS: Diabetes is common in Thailand, but one-half of all cases are undiagnosed. Because diagnosed diabetes is likely to be treated with proven, low-cost, preventive therapies such as glucose lowering and blood pressure lowering, initiatives that increased diagnosis rates would be expected to produce substantial health benefits in Thailand.