Comparison of the current WHO and new ADA criteria for the diagnosis of diabetes mellitus in three ethnic groups in the UK. American Diabetes Association

An Overview of the Eye in Diabetes

The three papers in this symposium are based on presentations to an RSM meeting on the Diabetic Eye, held on 9 April 2003. The matter is particularly topical because the National Service Framework for Diabetes calls for a high-quality retinal screening programme. After a review of the various ophthalmic conditions likely to be encountered in diabetic patients (A Negi, S A Vernon) we proceed to the most important, diabetic retinopathy, with a discussion of screening methods (D M Squirrell, J F Talbot) and an account of laser treatments (J G F Dowler). Colour versions of the clinical photographs are available online [www.jrsm.org]. Publication was coordinated by Professor Susan Lightman, of Moorfields Eye Hospital, London, UK.

New findings on type 2 diabetes in first-generation Chinese migrants settled in Italy: Chinese in Prato (CHIP) cross-sectional survey

BACKGROUND

Chinese people are one of the fastest growing immigrant populations in Europe, and their health has become a key issue to host nations. Although type 2 diabetes (T2DM) is a big burden among migrant populations, data on Chinese immigrants in Europe are limited.

METHODS

A cross-sectional survey was performed in 2014, adopting principles of community-based participatory research to investigate T2DM, diagnosed by the American Diabetes Association fasting criteria, in Chinese first-generation migrants aged 16 to 59 years settled in Prato (Italy). Association with different factors was investigated using logistic regression.

RESULTS

Of the 1608 participants, 177 had T2DM (11.0%), 119 being newly diagnosed (7.4%). Among subjects with diabetes, 58 (32.8%) were aware of the disease; among subjects with diabetes aware of their condition, 46 (79%) were treated with glucose lowering drugs. Age-standardized (World Health Organization 2001 population) prevalence of T2DM was 9.6% (95% CI 9.1 to 10.2%), being 12.0% (95% CI 11.0 to 12.9%) in men, and 7.8% (95% CI 7.1 to 8.4%) in women. At adjusted logistic regression, diabetes was associated with hypertension, current smoking, adiposity indices (waist circumference, waist-to-hip ratio, waist-to-height ratio, and body mass index), and high triglycerides. T2DM, adiposity indices, and high triglycerides were not associated with duration of stay in Italy.

CONCLUSIONS

The high prevalence of T2DM among first-generation Chinese immigrants in Europe stresses the need for specific health programs for T2DM early diagnosis, treatment, and prevention. There is an urgent need for policies to support this group because current policies will produce major social and economic costs. Copyright © 2016 John Wiley & Sons, Ltd.

Barriers and Facilitators to Healthy Lifestyle Changes in Minority Ethnic Populations in the UK: a Narrative Review

Minority ethnic populations experience a disproportionate burden of health inequalities compared with the rest of the population, including an increased risk of type 2 diabetes (T2DM). The purpose of this narrative review was to explore knowledge and attitudes around diabetes, physical activity and diet and identify barriers and facilitators to healthy lifestyle changes in minority ethnic populations in the UK. The narrative review focused on three key research topics in relation to barriers and facilitators to healthy lifestyle changes in minority adult ethnic populations: (i) knowledge and attitudes about diabetes risk; (ii) current behaviours and knowledge about physical activity and diet; and (iii) barriers and facilitators to living a healthier lifestyle. Nearly all of the studies that we identified reported on South Asian minority ethnic populations; we found very few studies on other minority ethnic populations. Among South Asian communities, there was generally a good understanding of diabetes and its associated risk factors. However, knowledge about the levels of physical activity required to gain health benefits was relatively poor and eating patterns varied. Barriers to healthy lifestyle changes identified included language barriers, prioritising work over physical activity to provide for the family, cultural barriers with regard to serving and eating traditional food, different perceptions of a healthy body weight and fear of racial harassment or abuse when exercising. Additional barriers for South Asian women included expectations to remain in the home, fear for personal safety, lack of same gender venues and concerns over the acceptability of wearing ‘western’ exercise clothing. Facilitators included concern that weight gain might compromise family/carer responsibilities, desire to be healthy, T2DM diagnosis and exercise classes held in ‘safe’ environments such as places of worship. Our findings suggest that South Asian communities are less likely to engage in physical activity than White populations and highlight the need for health promotion strategies to engage people in these communities. There is a gap in knowledge with regard to diabetes, physical activity, diet and barriers to healthy lifestyle changes among other ethnic minority populations in the UK; we recommend further research in this area.

On-chip, aptamer-based sandwich assay for detection of glycated hemoglobins via magnetic beads

Diabetes can be diagnosed and monitored by measurement of the cutoff ratio between glycated hemoglobins (HbA1c) and total hemoglobin (Hb), which does not require a fasting blood sample and is less influenced by biological variations. In this study, we combined the advantages of the microfluidic system and the selected low-cost, stable and specific aptamers and developed an integrated, aptamer-based microfluidic system for automatic glycated hemoglobin measurements. The detection process of human whole blood can be totally automated in this integrated microfluidic system. According to the experimental results, when compared to conventional bench-top manual assays, reagent consumption was significantly reduced by 75%, and the analysis time was reduced from 3.5h to 30 min. Besides, the novelty in this research also lies in the simultaneously performed two parallel assays for detection of Hb and HbA1c in a single chip. Therefore, this sensitive and low-cost aptamer-based microfluidic system may become a promising tool for point-of -care diagnosis of diabetes.

Improving Detection of Prediabetes in Children and Adults: Using Combinations of Blood Glucose Tests

Highlights

Aim

To determine combinations of blood glucose tests: oral glucose tolerance (OGT), fasting plasma glucose (FPG), and hemoglobin A1C (HbA1C) that are associated with highest diagnostic rates of prediabetes in non-diabetic American children and adults.

Methods

The 2007–2008 U.S. National Health and Nutrition Examination Surveys data were used for this study. Overall and specific prevalence of prediabetes (defined using OGT + FPG, OGT + HbA1C, HbA1C + FPG, and OGT + FPG + HbA1C tests) were determined across age, race/ethnicity, sex, and BMI categories.

Results

FPG + HbA1C test was associated with significantly higher diagnostic rates of prediabetes across age, race/ethnicity, and BMI. Estimates of overall prevalence of prediabetes using OGT + FPG, OGT + HbA1C, HbA1C + FPG, and OGT + FPG + HbA1C tests were 20.3, 24.2, 33, and 34.3%, respectively. Compared to OGT + FPG, the use of HbA1C + FPG test in screening was associated with 44.8, 135, 38.6, and 35.9% increased prevalence of prediabetes in non-Hispanic White, non-Hispanic Black, Mexican-American, and other racial/ethnic men, respectively. The corresponding values in women were 67.8, 140, 37.2, and 42.6%, respectively. Combined use of all blood glucose tests did not improve the overall and gender-specific prediabetes prevalence beyond what was observed using HbA1C + FPG test.

Conclusion

HbA1C criteria were associated with higher diagnosis rates of prediabetes than FPG and OGT tests in non-diabetic American children and adults. Using a combination of HbA1C and FPG test in screening for prediabetes reduces intrinsic systematic bias in using just HbA1C testing and offers the benefits of each test. A well-defined HbA1C that takes into consideration race/ethnicity, gender, age, and body mass index may improve detection of prediabetes in population and clinical settings.

The oral glucose tolerance test (OGTT) revisited

The oral glucose tolerance test (OGTT) has been the mainstay for diagnosing diabetes for decades. Recently, the American Diabetes Association (ADA) suggested abandoning the OGTT, while resorting to a simpler screening test, exclusively based on baseline fasting blood glucose concentration. This review article rewinds the history of OGTT and its recent advancements, and compares its power in detecting early diabetes with that of fasting blood glucose alone. The key point is that there are more diabetics originating from a population with normal fasting blood glucose than from subjects with impaired fasting glucose, those who can be detected by the new ADA recommendations. Conversely, the OGTT detects more efficiently early diabetes as well as subjects with IGT, as the glycemia at the second hour seems crucial as a diagnostic tool. We discuss the different significance of fasting versus second hour glycemia during OGTT, according to different mechanisms of glucose homeostasis. Finally, we provide recent evidence on very simple additional information that can be obtained from the OGTT, which renders this test even more useful, discussing pathophysiologic significance.

Screening for type 2 diabetes in a multiethnic setting using known risk factors to identify those at high risk: a cross-sectional study

Introduction

Screening enables the identification of type 2 diabetes mellitus (T2DM) during its asymptomatic stage and therefore allows early intervention which may lead to fewer complications and improve outcomes. A targeted screening program was carried out in a United Kingdom (UK) multiethnic population to identify those with abnormal glucose tolerance.

Methods

A sample of individuals aged 25–75 years (40–75 white European) with at least one risk factor for T2DM were invited for screening from 17 Leicestershire (UK) general practices or through a health awareness campaign. All participants received a 75 g oral glucose tolerance test, cardiovascular risk assessment, detailed medical and family histories and anthropometric measurements.

Results

In the 3,225 participants who were screened. 640 (20%) were found to have some form of abnormal glucose tolerance of whom 4% had T2DM, 3% impaired fasting glucose (IFG), 10% impaired glucose tolerance (IGT) and 3% both IFG and IGT. The odds of detecting IGT was approximately 60% greater (confounder-adjusted odds ratios [OR] 1.67 [1.22–2.29]) in the South Asian population.

Conclusions

Around one in five people who had targeted screening have IGT, IFG or T2DM, with a higher prevalence in those of South Asian origin. The prevalence of undetected T2DM is lower in South Asians compared to previously published studies and maybe due to increased awareness of this group being at high risk.

Prevalence and correlates of diabetes in South asian indians in the United States: findings from the metabolic syndrome and atherosclerosis in South asians living in america study and the multi-ethnic study of atherosclerosis

BACKGROUND

Individuals from South Asia have high diabetes prevalence despite low body weight. We compared the prevalence of diabetes among South Asian Indians with other U.S. ethnic groups and explored correlates of diabetes.

METHODS

This was a cross-sectional study of 150 South Asian Indians (ages 45-79) in California, using similar methods to the Multi-Ethnic Study of Atherosclerosis (MESA). Type 2 diabetes was classified by fasting plasma glucose (FPG) >or=126 mg/dL, 2-h postchallenge glucose >or=200 mg/dL, or use of hypoglycemic medication.

RESULTS

A total of 29% of Asian Indians had diabetes, 37% had prediabetes, and 34% had normal glucose tolerance. After full adjustment for covariates, Indians still had significantly higher odds of diabetes compared to whites and Latinos, but not significantly different from African Americans and Chinese Americans in MESA: Indians [odds ratio (OR), 1.0], whites [OR, 0.29; 95% confidence interval (CI), 0.17-0.49], Latinos (OR, 0.59; CI, 0.34-1.00) African Americans (OR, 0.77; CI 0.45-1.32), Chinese Americans (OR, 0.78, CI, 0.45-1.32). Variables associated with prediabetes or diabetes among Indians included hypertension, fatty liver, visceral adiposity, microalbuminuria, carotid intima media thickness, and stronger traditional Indian beliefs.

CONCLUSIONS

Indian immigrants may be more likely to have diabetes than other U.S. ethnic groups, and cultural factors may play a role, suggesting that this is a promising area of research.

Differences in height explain gender differences in the response to the oral glucose tolerance test- the AusDiab study

AIM

To determine the extent of gender-related differences in the prevalence of glucose intolerance for the Australian population and whether body size may explain such differences.

METHODS

Cross-sectional data were collected from a national cohort of 11 247 Australians aged > or = 25 years. Glucose tolerance status was assessed according to both fasting plasma glucose (FPG) and 2-h plasma glucose (2hPG) levels following a 75-g oral glucose tolerance test (OGTT). Anthropometric and glycated haemoglobin measurements were also made.

RESULTS

Undiagnosed diabetes and non-diabetic glucose abnormalities were more prevalent among men than women when based only on the FPG results (diabetes: men 2.2%, women 1.6%, P = 0.02; impaired fasting glycaemia: men 12.3%, women 6.6%, P < 0.001). In contrast 16.0% of women and 13.0% of men had a 2hPG abnormality (either diabetes or impaired glucose tolerance, P = 0.14). Women had a mean FPG 0.3 mmol/l lower than men (P < 0.001), but 2hPG 0.3 mmol/l higher (P = 0.002) and FPG-2hPG increment 0.5 mmol/l greater (P < 0.001). The gender difference in mean 2hPG and FPG-2hPG increment disappeared following adjustment for height. For both genders, those in the shortest height quartile had 2hPG levels 0.5 mmol/l higher than the tallest quartile, but height showed almost no relationship with the FPG.

CONCLUSIONS

Men and women had different glycaemic profiles; women had higher mean 2hPG levels, despite lower fasting levels. It appeared that the higher 2hPG levels for women related to lesser height and may be a consequence of using a fixed glucose load in the OGTT, irrespective of body size.

The combination of fasting plasma glucose and glycosylated hemoglobin predicts type 2 diabetes in Japanese workers

OBJECTIVES

We examined the usefulness of the combined use of fasting plasma glucose (FPG) and hemoglobin Alc (HbA1c) levels to predict the progression of diabetes in a Japanese population.

METHODS

A retrospective cohort study was conducted from 1995 to 2002 among 449 non-diabetic Japanese workers, ages 23-65, in whom baseline FPG levels and HbA1c were measured. Subjects were classified into six groups according to their baseline FPG level: low normal fasting glucose (NFG) (<5.55 mmol/l); high NFG (5.55-6.09 mmol/l); or impaired fasting glucose (IFG) (6.10-6.99 mmol/l), in combination with baseline HbA1c level: low HbA1c (<5.8%) and high HbA1c (> or =5.8%). The cumulative incidence of diabetes in 2002, as defined by the 1997 American Diabetes Association (ADA) diagnostic criteria, was compared between groups.

RESULTS

The overall cumulative incidence of diabetes was 3.8% (17/449). The cumulative incidence of diabetes was 0.6% (2/339) in those with low NFG/normal HbA1c; 0% (0/24) with low NFG/high HbA1c; 6.4% (3/47) with high NFG/normal HbA1c; 23.1% (3/13) with high NFG/high HbA1c; 17.6% (3/17) with IFG/normal HbA1c; and 66.7% (9/17) with IFG/high HbA1c. The odds ratios for diabetes, adjusted for age, sex, body mass index (BMI) and family history of diabetes, were 5.3 (95% CI, 3.0-9.3) and 3.0 (1.7-5.3), per 0.56 mmol/l increase in FPG and 0.5% increase in HbA1c, respectively.

CONCLUSIONS

The combined use of FPG and HbA1c levels predicts the progression to diabetes in individuals with no apparent risk. In particular, the combination is recommended for individuals with a FPG > or =5.55 mmol/l.

Diabetes prevalence in England, 2001--estimates from an epidemiological model

AIMS

To estimate the total prevalence of diabetes mellitus (diagnosed and undiagnosed) at national, regional and local level in England to support health-care planning and delivery.

METHODS

An epidemiological model was constructed by applying age-sex-ethnic-specific reference prevalence rates from epidemiological studies to resident populations (2001 census) of England at national, regional, and local authority/Primary Care Trust levels.

RESULTS

Estimated prevalence of total diabetes for all persons in England was 4.41% in 2001, equating to 2 168 000 persons. Type 2 diabetes was estimated to affect 2 002 000 persons (92.3%) and Type 1 diabetes 166 000 persons (7.7%). Diabetes prevalence was estimated to be higher in women (5.17%) than men (3.61%). People from ethnic minority groups had higher crude prevalence than White Europeans (4.29, 5.69, 6.63 and 2.13% among White Europeans, Black African/Caribbeans, South Asians and 'other' groups, respectively). Prevalence increased sharply with age (0.33, 3.37 and 13.92%, respectively, in those aged 0-29, 30-59 and 60+ years). The model allows use of user-defined population denominator estimates to derive numbers and prevalence of people with diabetes for a given local population group, such as at ward or general practice level.

CONCLUSIONS

Self-reported diabetes prevalence estimates from community surveys underestimate the true burden of diabetes. The model can be used to derive the expected total prevalence of diabetes in health areas that lack reliable data to facilitate the implementation of the National Service Framework for diabetes. It will also allow estimates of future diabetes prevalence to be derived, and can potentially be used for prevalence estimates in all of the UK.

Prevalence of diabetes and impaired glucose regulation in 45- to 64-year-old individuals in three areas of Finland

AIMS

To determine the prevalence of diabetes mellitus (DM), impaired glucose tolerance (IGT) and impaired fasting glycaemia (IFG) and possible regional differences in Finnish adults aged between 45 and 64 years.

METHODS

A population sample of 2642 subjects aged between 45 and 64 years living in three geographical areas in Finland was invited to an oral glucose tolerance test.

RESULTS

The glucose tolerance status of 2087 subjects (79.0%) was determined. The age-standardized prevalence of DM in men and women was 10.2% and 7.4%, respectively (P = 0.020 for difference between sexes), and that of IGT 10.5% in men and 9.2% in women. IFG in men was more than twice as common as in women (13.5% vs. 5.0%, respectively, P < 0.001). Abnormal glucose tolerance was most common in southern compared with southwestern and eastern Finland. Of all diabetic subjects, 44% were previously undiagnosed.

CONCLUSIONS

The age-standardized prevalence of DM in 45- to 64-year-old Finns was within the range defined in previous studies on Europid populations. DM and IFG were more common in men than in women. Regional differences in the prevalence of abnormal glucose regulation suggest differences in lifestyle within an ethnically homogenous population.

Type II Diabetes Mellitus and impaired glucose tolerance in Yemen: prevalence, associated metabolic changes and risk factors

OBJECTIVE

To investigate the prevalence of type II Diabetes Mellitus (DM) and impaired glucose tolerance (IGT) and identify the metabolic abnormalities and risk factors associated with these conditions in an urban city of Yemen.

RESEARCH DESIGN AND METHODS

Cross-sectional, population-based study investigating 498 adults (245 males and 253 females) aged 25-65 years. The 1999 modified World Health Organization criteria were adopted for the diagnosis of Diabetes Mellitus and IGT. A standard questionnaire was applied and blood lipids, blood pressure, body mass index (BMI) and waist/hip ratio (WHR) were determined.

RESULTS

The overall prevalence of type II Diabetes Mellitus was 4.6% (7.4% in males and 2% in females). Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) were found in 2% and 2.2% of the study population. Factors independently related to any abnormality in glucose tolerance, using logistic regression analysis, were sex, hyperlipidaemia, hypertriglyceridaemia, and hypertension; whereas sex and age related to DM. More than 80% of the type II diabetics were over the age of 40, 35% being hyperlipidaemic, 22% being hypertensive and 18% obese. Sixty percent of IGT subjects were hyperlipidaemic and 20% were obese. Approximately 78% of obese individuals (>/=30 kg/m(2)) had normal glucose tolerance.

CONCLUSION

The prevalence of type II DM and its potential increase reflected by the high prevalence of obesity in normal glucose tolerance subjects in the Yemeni population constitutes a major public health problem.

Changes in prevalence and site of care of diabetes in a health district 1991-2001

AIMS

Alongside a rising prevalence of known diabetes, patterns of care for diabetes have been changing in the United Kingdom. The aim of this study is to describe the changes in the prevalence of known diabetes and shift in site of care of patients in a single health district over a 10-year period.

METHODS

Repeat cross-sectional study over 10 years of patients with diabetes resident in North Tyneside district.

RESULTS

The crude prevalence of known diabetes in North Tyneside rose from 1.1 to 3.0% between 1991 and 2001. The proportion of patients receiving their diabetes care wholly in primary care rose significantly from 608/2236 (27%) in 1991 to 3995/5809 (69%) in 2001 (chi(2) = 968, 1 d.f., P < 0.001). The number of patients attending secondary care also rose by 14% over this period of time from 1508 to 1712 patients.

CONCLUSIONS

Most of the extra workload of the rising prevalence of diabetes has been met in primary care. However, hospital care has not seen a drop in workload. This has important implications for health care planning, as an increase in resources will be required within both primary and secondary care to meet the needs of the diabetic population.

Habitual fish consumption and glycated haemoglobin: the EPIC-Norfolk study

OBJECTIVE

To investigate the association between habitual fish consumption and a continuous measure of glycaemia.

DESIGN

Cross-sectional study.

SETTING

EPIC-Norfolk, a population-based cohort study of diet and chronic disease.

SUBJECTS AND METHODS

In all, 4500 men and 5509 women, aged 40-78 y, without self-reported diabetes. Diet was assessed by a semiquantitative food frequency questionnaire, and glycaemia was measured by glycated haemoglobin.

RESULTS

In women only, in analyses adjusted for age, the HbA(1c) level was positively associated with eating fried fish and inversely associated with eating oily fish (b=0.036, 95% confidence interval (CI): 0.0033, 0.069; and b=-0.046, 95% CI:-0.086, -0.0064 respectively). These associations were attenuated by adjustment for family history of diabetes, smoking status and physical activity level, but the association with fried fish remained statistically significant (b=0.033, 95% CI: 0.00056, 0.066). Adjusting for total energy, alcohol, fruit and vegetable intakes resulted in further attenuation and both associations were no longer statistically significant. In men, there was no evidence that HbA(1c) level was associated with fish consumption.

CONCLUSIONS

The study found no evidence of an association between fish consumption and HbA(1c) after taking other lifestyle factors into account.

The performance of a risk score as a screening test for undiagnosed hyperglycemia in ethnic minority groups: data from the 1999 health survey for England

OBJECTIVE

To assess the performance of the Cambridge Risk Score (CRS) to predict undiagnosed hyperglycemia in Caribbean and South Asian people living in the U.K.

RESEARCH DESIGN AND METHODS

The CRS uses routinely available data from primary care records to identify people at high risk for undiagnosed type 2 diabetes. The sensitivity, specificity, and area under the receiver operator characteristic (ROC) curve for the CRS cut point of 0.199 were 77, 72, and 80% (95% CI 68-91), respectively. The risk score was calculated for 248 Caribbean and 555 South Asian participants aged 40-75 years in the 1999 Health Survey for England. Undiagnosed hyperglycemia was considered present if fasting plasma glucose was >/=7.0 mmol/l or HbA(1c) was >/=6.5%. Sensitivity, specificity, and predictive values were calculated for various cut points of the risk score, and ROC curves were constructed.

RESULTS

The area under the ROC curve was 67% (59-76) and 72% (67-78) for Caribbeans and South Asians, respectively. The optimal cut point in Caribbean participants was 0.236, sensitivity was 63% (46-77), and specificity was 63% (56-69). In the South Asian population, the optimal cut point was and 0.127, sensitivity was 69% (60-78), and specificity was 64% (60-69).

CONCLUSIONS

The CRS, using routinely available data, can be used in a strategy to detect undiagnosed hyperglycemia in Caribbean and South Asian populations. The existence of ethnic group-specific cut points must be further established in future studies.

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.

Hidden diabetes in the UK: use of capture-recapture methods to estimate total prevalence of diabetes mellitus in an urban population

An early requirement of the UK's Diabetes National Service Framework is enumeration of the total affected population. Existing estimates tend to be based on incomplete lists. In a study conducted over one year in North Liverpool, we compared crude prevalence rates for type 1 and type 2 diabetes with estimates obtained by capture-recapture (CR) analysis of multiple incomplete patient lists, to assess the extent of unascertained but diagnosed cases. Patient databases were constructed from six sources-a hospital diabetes centre; general practitioner registers; hospital admissions with a diagnosis of diabetes; a hospital diabetic retinal clinic; a research list of patients with diabetes admitted with stroke; and a local children's hospital. Log linear modelling was used to estimate missing cases, hence total prevalence. The crude prevalence of diabetes was 1.5% (95% confidence interval [CI] 1.41, 1.52), compared with a CR-adjusted rate of 3.1% (CI 3.03, 3.19). Age-banded CR-adjusted prevalence was always higher in males than in females and the difference became more pronounced with increasing age. Among males, CR-adjusted prevalence rose from 0.4% at age 10-19 years to 18.3% at 80+ years; in females the corresponding figures were 0.4% and 9.3%. The gap between crude and CR-estimated prevalence points to a rate of 'hidden diabetes' that has substantial implications for future diabetes care.

Insulin secretion and action show differences in impaired fasting glucose and in impaired glucose tolerance in Asian Indians

BACKGROUND

The aim of the study was to compare the abnormalities in insulin secretion and insulin sensitivity in impaired fasting glucose (IFG) and in impaired glucose tolerance (IGT).

METHODS

Glucose tolerance was determined by oral glucose tolerance test in 289 non-diabetic subjects selected for this study (M : F, 160 : 129, mean age 42.2 +/- 11.0 (SD) years, mean body mass index (BMI) 24.9 +/- 4.2 kg/m(2)). Diabetic subjects were excluded from the study. The association of insulin resistance and beta-cell function (calculated by HOMA model) with IFG and IGT was studied using linear and multiple logistic regression analyses. Subjects with normoglycaemia (NGT) were used as controls.

RESULTS

Insulin resistance was significantly more in IFG and in IGT than in NGT. beta-cell dysfunction was significantly higher in IFG than in IGT. IFG was associated with both insulin resistance (OR = 9.11, p < 0.001) and beta-cell dysfunction (inverse correlation, OR = 0.103, p < 0.001), while only insulin resistance was significantly associated with IGT (OR = 1.24, p = 0.005).

CONCLUSIONS

In urban South Asian Indians, IFG differed from IGT in having combined insulin resistance and beta-cell dysfunction, while IGT was associated only with insulin resistance.

Hidden diabetes in the UK: use of capture-recapture methods to estimate total prevalence of diabetes mellitus in an urban population

An early requirement of the UK's Diabetes National Service Framework is enumeration of the total affected population. Existing estimates tend to be based on incomplete lists. In a study conducted over one year in North Liverpool, we compared crude prevalence rates for type 1 and type 2 diabetes with estimates obtained by capture-recapture (CR) analysis of multiple incomplete patient lists, to assess the extent of unascertained but diagnosed cases. Patient databases were constructed from six sources-a hospital diabetes centre; general practitioner registers; hospital admissions with a diagnosis of diabetes; a hospital diabetic retinal clinic; a research list of patients with diabetes admitted with stroke; and a local children's hospital. Log linear modelling was used to estimate missing cases, hence total prevalence. The crude prevalence of diabetes was 1.5% (95% confidence interval [CI] 1.41, 1.52), compared with a CR-adjusted rate of 3.1% (CI 3.03, 3.19). Age-banded CR-adjusted prevalence was always higher in males than in females and the difference became more pronounced with increasing age. Among males, CR-adjusted prevalence rose from 0.4% at age 10-19 years to 18.3% at 80+ years; in females the corresponding figures were 0.4% and 9.3%. The gap between crude and CR-estimated prevalence points to a rate of 'hidden diabetes' that has substantial implications for future diabetes care.

An overview of the eye in diabetes

The three papers in this symposium are based on presentations to an RSM meeting on the Diabetic Eye, held on 9 April 2003. The matter is particularly topical because the National Service Framework for Diabetes calls for a high-quality retinal screening programme. After a review of the various ophthalmic conditions likely to be encountered in diabetic patients (A Negi, S A Vernon) we proceed to the most important, diabetic retinopathy, with a discussion of screening methods (D M Squirrell, J F Talbot) and an account of laser treatments (J G F Dowler). Colour versions of the clinical photographs are available online [www.jrsm.org]. Publication was coordinated by Professor Susan Lightman, of Moorfields Eye Hospital, London, UK.

Implementing intensive control of blood glucose concentration and blood pressure in type 2 diabetes in England: cost analysis (UKPDS 63)

OBJECTIVE

To estimate the incremental cost of implementing policies for intensive control of blood glucose concentration and blood pressure for all patients with type 2 diabetes in England.

DESIGN

Extrapolation of resource use and cost data derived from a randomised controlled trial.

SETTING

General practice, outpatient care, and inpatient care.

POPULATION

Trial population with diagnosed type 2 diabetes in England extrapolated to the population of England.

MAIN OUTCOME MEASURES

Total costs based on use of healthcare resources including costs of management, treatment, and hospitalisation.

RESULTS

The incremental net annual cost of implementing intensive control of blood glucose and blood pressure to all people with diagnosed type 2 diabetes in England is estimated to be pound 100.5m ($156m; euro;159m), which is equivalent to less than 1% of the proposed additional annual expenditure on the NHS in 2001-5. This estimate varied in sensitivity analyses from pound 67m to pound 121m.

CONCLUSIONS

Policies to improve control of blood glucose and blood pressure of people with type 2 diabetes are effective in reducing complications associated with the disease and are also cost effective. The total cost represents a small fraction of the NHS's spending plans.

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.

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 > or = 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.

Diabetes and cardiovascular disease

This review focuses on several topics related to the epidemiology of diabetes and cardiovascular disease (CVD). These include the CVD risk factors common in the metabolic syndrome, behavioral risk factors and diabetes, gender differences in the association between diabetes and CVD risk, and how the clinical definition of diabetes influences the association of diabetes and CVD. Nontraditional risk factors potentially linking diabetes and CVD are also discussed, including chronic inflammation, advanced glycation endpoints, autonomic neuropathy, sleep-disordered breathing, and genetic susceptibility to diabetes-associated CVD risk.

Lipid lowering in patients with diabetes mellitus: what coronary heart disease risk threshold should be used?

OBJECTIVE

To examine the impact for the UK population of providing statin treatment for diabetic patients for the primary prevention of coronary heart disease at a coronary event risk lower than currently recommended by the National Service Framework (NSF) for coronary heart disease.

DESIGN

Cross sectional survey.

SETTING

England 1998.

PARTICIPANTS

Nationally representative sample of 6879 subjects aged 35-74 years living in private households.

MAIN OUTCOME MEASURES

The proportion of the UK population recommended for statin treatment according to the NSF for coronary heart disease, and the proportion of the population with diabetes at a coronary disease event risk of > or = 15% over 10 years.

RESULTS

Of the 6879 subjects with total cholesterol measurements, 218 (3.2%) had diabetes mellitus. In this nationally representative sample, 6.3% of the subjects (95% confidence interval (CI), 5.7% to 6.9%) were candidates for statin treatment for the secondary prevention of coronary heart disease, including 0.7% (95% CI 0.5% to 0.9%) with diabetes. A further 2.4% (95% CI 2.0% to 2.8%), including 0.4% (0.2% to 0.6%) with diabetes, were identified as candidates for primary prevention of coronary heart disease according to the NSF for coronary heart disease. Lowering the primary prevention threshold for statin treatment to a coronary event risk of > or = 15% over 10 years in diabetic patients identified an additional 0.5% of the population.

CONCLUSIONS

Extending statin treatment to diabetic patients at a coronary heart disease risk of > or = 15% over 10 years would have a relatively small numerical impact in the UK population. Thus patients with diabetes mellitus should, as a minimum, be targeted for statin treatment at this level of risk.

Diagnosis of diabetes mellitus and intermediate glucose abnormalities in obese patients based on ADA (1997) and WHO (1985) criteria

AIM

To assess the accuracy of the 1997 ADA criteria for diagnosing diabetes mellitus and related glucose disturbances in comparison with the reference WHO 1985 criteria in obese subjects.

PATIENTS AND METHODS

In 286 men and 881 women, 15-84 years of age, with obesity (body mass index (BMI) > or = 30 kg/m2), an oral glucose tolerance test (OGTT) was carried out according to WHO standard. Patients were classified into three categories of glucose tolerance using WHO 1985 (Normal Glucose Tolerance (NGT), Impaired Glucose Tolerance (IGT) and Diabetes Mellitus (DM)) and ADA (Normal Fasting Glucose (NFG), Impaired Fasting Glucose (IFG) and DM) criteria. Prevalence of each category was compared and agreement between the two classifications was assessed. The relation between fasting plasma glucose value and diabetes, as diagnosed by WHO 1985 criteria, was studied using various regression models, cumulative frequency curves, Finch method and ROC curve.

RESULTS

Compared with WHO 1985, ADA criteria strongly underestimated the prevalence rate of diabetes (3.7% vs. 10.6%) and intermediate glucose abnormalities (6.0% vs. 22.4%). Agreement between the two classifications was poor (kappa = 0.23). Moreover, many patients defined as glucose-intolerant by the WHO 1985 criteria were shifted to a more favourable metabolic status by ADA criteria. Thus, ADA criteria failed to detect 69% of WHO diabetic patients and 89% with IGT were considered as normal. According to the method, cut-off value of fasting blood glucose for detecting WHO 1985-diagnosed diabetes varied widely, from 5.3 to 6.3 mmol/l and none was satisfactory because of poor sensitivity and positive predictive value.

CONCLUSION

The ADA criteria do not appear to be a good substitute for those of the WHO 1985 at identifying diabetes and intermediate glucose abnormalities in an obese population. Since it appears impossible to determine a reliable cut-off value for fasting blood glucose to identify diabetic obese subjects with sufficient sensitivity, our results justify the retention of the OGTT in clinical practice or for epidemiological studies.

High prevalence of type 2 diabetes in all ethnic groups, including Europeans, in a British inner city: relative poverty, history, inactivity, or 21st century Europe?

OBJECTIVE

To compare the prevalence of type 2 diabetes in white Europeans and individuals of African-Caribbean and Pakistani descent.

RESEARCH DESIGN AND METHODS

Random sampling of population-based registers in inner-city Manchester, Britain's third most impoverished area. A total of 1,318 people (25-79 years of age) were screened (minimum response 67%); 533 individuals without known diabetes underwent 2-h glucose tolerance testing, classified by 1999 World Health Organization criteria.

RESULTS

More than 60% of individuals reported household annual income < pound10,000 ($15,000) per year. Energetic physical activity was rare and obesity was common. Age-standardized (35-79 years) prevalence (mean 95% CI) of known and newly detected diabetes was 20% (17-24%) in Europeans, 22% (18-26%) in African-Caribbeans, and 33% (25-41%) in Pakistanis. Minimum prevalence (assuming all individuals not tested were normoglycemic) was 11% (8-14%), 19% (15-23%), and 32% (24-40%), respectively. Marked changes in prevalence represent only small shifts in glucose distributions. Regression models showed that greater waist girth, lower height, and older age were independently related to plasma glucose levels, as was physical activity. Substituting BMI and waist-to-hip ratio revealed their powerful contribution.

CONCLUSIONS

A surprisingly high prevalence of diabetes, despite expected increases with new lower criteria, was found in Europeans, as previously established in Caribbeans and Pakistanis. Lower height eliminated ethnic differences in regression models. History and relative poverty, which cosegregate with obesity and physical inactivity, are likely contributors. Whatever the causes, the implications for health services are alarming, although substantial preventive opportunities through small reversals of glucose distributions are the challenge.

Plasma glucose reference interval in a low-risk population. 2. Impact of the new WHO and ADA recommendations on the diagnosis of diabetes mellitus

The aim of the study was to establish a reference interval of fasting venous plasma glucose (FPG) from healthy individuals. A prospective modified cross-sectional population-based study was made with random selection of 2100 persons in age-stratified groups > or = 18 years identified from the local Personal Identification Register. The invitation was accepted by 755 persons, of which 726 aged 18-92 years were eligible. They did not have a diabetes diagnosis, were non-pregnant and capable of fasting for 8 h. All participants filled in a questionnaire on medical risk factors. Blood for the FPG and haemoglobin Alc (HbAlc) measurements was drawn in accordance with a standardized procedure. A total of 302 participants carried diabetes risk indicators and were ruled out. The FPG concentrations in the remaining low-risk population (n=424) was ln Gaussian distributed. The FPG 97.50 centile in this group was 6.4 mmol/L (95% CI: 6.3-6.5 mmol/L), in contrast to the WHO and ADA theoretical limit of 6.1 mmol/L. Their diagnostic decision limit of 7.0 mmol/L FPG corresponded to the 99.86 centile of the FPG reference distribution (95% CI: 6.8-7.1). Subclassification of the reference population showed increasing FPG with increasing BMI and age and was higher in men than in women. The study determined the FPG 95% interfractile reference interval in a healthy population. The interval in glucose concentration between the 97.5 centile of the reference interval and the ADA-WHO diagnostic limit is very narrow. The clinical application of the diagnostic discriminator and the interpretation of the WHO-ADA grey zone from 6.1 to 7.0 mmol/L FPG may consequently be biased because of poorly defined limits and influence from BMI, age and gender.

Non-industrialised countries and affluence

The prevalence of type 2 diabetes is rising rapidly in all non-industrialised populations. By 2025, three-quarters of the world's 300 million adults with diabetes will be in non-industrialised countries, and almost a third in India and China alone. There is strong evidence that this epidemic has been triggered by social and economic development and urbanisation, which are associated with general improvements in nutrition and longevity, but also with obesity, reduced physical exercise and other diabetogenic factors. There is evidence too that fetal growth retardation and growth failure in infancy, both still widespread in non-industrialised populations, increase susceptibility to diabetes. An additional factor may be intergenerational effects of gestational diabetes occurring in mothers who grew poorly in early life and become obese as adults. Prevention of type 2 diabetes will require measures to promote exercise and reduce obesity in adults and children, alongside programmes to achieve healthy fetal and infant growth.

Fibrinogen, other cardiovascular risk factors and diabetes mellitus in Hong Kong: a community with high prevalence of Type 2 diabetes mellitus and impaired glucose tolerance

AIMS

To determine the prevalence of Type 2 diabetes mellitus and impaired glucose tolerance (IGT) and their relationships to fibrinogen and other cardiovascular risk factors in Hong Kong Chinese.

METHODS

A probability sample of 1,316 men and 1,348 women aged 25-74 years were examined in a population-based cross-sectional study.

RESULTS

A total of 3.0% (95% confidence interval 2.1-3.9) of men had previously diagnosed (known) and 6.4% (5.0-7.8) newly diagnosed (unknown) diabetes, 14.4% (12.4-16.5) had IGT and 79.2% were normal by 1985 WHO diagnostic criteria; corresponding prevalences in women were 3.7% (2.7-4.7), 5.9% (4.6-7.2), 17% (14.8-19.2) and 73.4%. The age-standardized prevalence of Type 2 diabetes for the 35-64 age group was 9.5% (7.5-11.6) in men and 10.2% (8.0-12.4) in women. Age-adjusted mean fibrinogen levels in these four groups (normal/IGT/unknown diabetes/known diabetes) with decreasing degrees of glucose tolerance (diabetes status) were 2.80, 2.57, 2.51 and 2.47 g/l (P = 0.003) in men, and 2.86, 2.72, 2.67, 2.61 g/l (P = 0.005) in women. Age, obesity, systolic blood pressure and triglycerides were significantly associated with diabetes status in both sexes, fibrinogen in men only and high density lipoprotein cholesterol negatively in women.

CONCLUSIONS

The prevalence of Type 2 diabetes mellitus was very high especially in older subjects, and fibrinogen was associated with increasing glucose intolerance in men but not in women. The detection and better control of cardiovascular risk factors, particularly hypertension in this developed Chinese community with a high prevalence of diabetes and glucose intolerance, is particularly important.

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.

The prevalence of diabetes, association with cardiovascular risk factors and implications of diagnostic criteria (ADA 1997 and WHO 1998) in a 1996 community-based population study in Hong Kong Chinese. Hong Kong Cardiovascular Risk Factor Steering Committee. American Diabetes Association

AIMS

While the American Diabetes Association (ADA) 1997 diagnostic criteria advocate the use of fasting plasma glucose only, the World Health Organization (WHO) criteria retain the use of the standard oral glucose tolerance test (OGTT). The present study evaluated the relative merit of the respective diagnostic criteria in Chinese.

METHODS

Data collected for the Hong Kong Cardiovascular Risk Factor Prevalence Study was analysed. This was a representative population-based study, conducted from 1995 to 1996 among 2,900 Chinese subjects aged 25-74 years using a 75-g OGTT.

RESULTS

The prevalence of diabetes (known plus unknown) was 6.2% (95% confidence interval 5.3-7.1%), 9.2% (8.1-10.3%), and 9.8% (8.7-10.9%) based on ADA 1997, WHO 1985 and WHO 1998 criteria, respectively, with a very high prevalence in older subjects. The 2,451 subjects classified as normal under ADA 1997 criteria were heterogenous: 15.3% had impaired glucose tolerance; 2.1% had diabetes under WHO 1998 criteria. These latter two smaller groups had cardiovascular risk profiles comparable to that found among the impaired fasting glucose subjects (under ADA), but worse than that among the concordant normal glucose tolerance subjects.

CONCLUSIONS

The ADA criteria underestimate both diabetes prevalence and cardiovascular risk in this population. Hence fasting glucose alone is an inadequate approach and OGTT should be retained to identify at-risk individuals in both clinical diagnosis and epidemiological studies.

Comparison of WHO and ADA criteria for diagnosis of glucose status in adults

The aim was to compare the 1997 American Diabetes Association (ADA) and 1985 and 1998 World Health Organisation (WHO) criteria for the diagnosis of diabetes and impaired glucose tolerance (IGT) by ethnicity and cardiovascular risk factors. We analysed the oral glucose tolerance tests carried out in a cross-sectional survey of 5816 New Zealand workers aged 22-78 years (4211 men, 1605 women) carried out between 1988 and 1990. Prevalence of diabetes was similar using ADA (3.1%) compared with the 1998 WHO criteria (3.0%). The overall prevalence rate of diabetes using the 1985 WHO criteria was only 1.5%. The prevalence rate of impaired fasting glucose (IFG) was the lowest in Europeans (7.3%) and highest in Asians (15.0%). The overall weighted kappa for agreement between the 1997 ADA and 1998 WHO criteria was moderate (0.59), but varied between ethnic groups. Cardiovascular disease (CVD) risk factors were approximately more adverse across groups with IFG, normal (ADA)/IGT (WHO), IFG/IGT and diabetes compared with normal subjects. Compared to those with IFG, participants with the normal (ADA)/IGT (WHO) criteria differed in fasting and 2-h glucose, diastolic blood pressure, and urinary albumin levels, and the proportions of males and number with hypertension, but had a significantly adverse pattern of CVD risk factors compared to those with normal glycaemia. The 1988 WHO criteria using the OGTT provides additional information for classifying various categories of glucose intolerance that is not captured using the 1997 ADA fasting glucose criteria alone.

Impaired glucose tolerance and fasting hyperglycaemia have different characteristics

AIMS

Use of the oral glucose tolerance test (OGTT) to define glucose intolerance in the general population may bias towards selection of those with insulin resistance. Beta cell function and insulin resistance markers were analysed in four groups: controls (n = 101); fasting hyperglycaemia (FH, n 45); impaired glucose tolerance; (IGT, n = 16) and those with features of both FH and IGT ('Both', n = 30).

METHODS

Subjects underwent an OGTT. Plasma glucose, fasting lipid profiles, fasting, 30 and 120 min insulin were measured and beta cell function (% B) and insulin sensitivity (% S) assessed by homeostatic model assessment (HOMA) RESULTS: The FH group compared to controls had a significantly lower % B. The IGT group compared to controls had features of insulin resistance (higher body mass index (BMI), systolic blood pressure and 2 h insulin concentration). Subjects with 'both' IGT and FH had features of insulin resistance (higher BMI, systolic and diastolic blood pressure and triglyceride concentration) as well as beta cell dysfunction with a lower % B and 30 min insulin-glucose ratio compared to controls. There was a preponderance of males in this group. In all, 192 subjects' 30-min insulin concentration and incremental insulin response showed only a significantly negative correlation with fasting glucose concentration. In a linear regression analysis, a low 30-min insulin-glucose ratio was only a significant factor in the fasting glucose model. Thus, higher fasting glucose concentrations appear to be associated with beta cell dysfunction. However, HbA1 only showed a significant correlation with 120-min glucose, not fasting glucose concentration.

CONCLUSIONS

In those with milder degrees of glucose intolerance, FH is associated with beta cell dysfunction and those with IGT and a relatively 'normal' fasting glucose have features of the insulin resistance syndrome.

Application of the new ADA criteria for the diagnosis of diabetes to population studies in sub-Saharan Africa. American diabetes association

AIMS

To examine the implications for epidemiological studies of the American Diabetes Association (ADA) recommendation that the fasting blood glucose at a lowered level becomes the main diagnostic test for diabetes on cross-sectional-based data from sub-Saharan Africa.

METHODS

Data from 11 surveys conducted in rural, peri-urban and urban Cameroon (n = 1804), South Africa (n = 3799) and Tanzania (n = 10013) which measured fasting (ADA criteria) and 2-h blood glucose concentrations during a standard 75 g OGTT (old WHO criteria) were analysed.

RESULTS

The prevalence of diabetes was higher in eight of the 11 surveys when applying the new ADA compared to the old WHO criteria. With the exception of one population (Mara, Tanzania) the absolute difference in prevalence between the two classifications tended to be small (< 2%). There was considerable variation in the categorization of individuals using the ADA and old WHO criteria. The level of agreement between the two ranged from fair to good (Kappa statistic 0.17-0.86). The prevalence of impaired fasting glycaemia (IFG) was lower than that of impaired glucose tolerance (IGT) in 10 of the surveys and the agreement between the two was fair, < or = 0.26 in all the surveys.

CONCLUSIONS

Although the use of the new ADA fasting criteria for prevalence surveys is an attractive and practical option, particularly in Africa, further information is required on the characteristics and prognosis of individuals classified as IFG or diabetic by the fasting criteria, prior to wide adoption of the ADA criteria. Ideally measurement of both fasting and two low glucose concentrations should remain the standard for epidemiological studies.

Comparison of glucose tolerance categories in the Korean population according to World Health Organization and American Diabetes Association diagnostic criteria

OBJECTIVES

To compare the prevalence and metabolic profiles of glucose tolerance categories according to World Health Organization(WHO) and 1997 American Diabetes Association(ADA) fasting criteria for the diagnosis of diabetes mellitus and impaired glucose metabolism in the Korean population.

METHODS

2251 subjects without previous history of diabetes, who participated in the Yonchon diabetes epidemiology survey in 1993, were classified according to both criteria. The prevalence of glucose tolerance categories and the agreement across all categories of glucose tolerance were calculated. Metabolic characteristics of different glucose tolerance categories were compared.

RESULTS

The prevalence of diabetes and impaired fasting glucose(IFG) according to ADA fasting criteria was similar to those of diabetes and impaired glucose tolerance(IGT) according to WHO criteria, respectively. However, 35.5% of the subjects who were diagnosed as diabetes by WHO criteria were reclassified as either IFG or normal fasting glucose (NFG), and 38.5% of diabetic patients according to ADA fasting criteria were IGT or normal glucose tolerance (NGT) by WHO criteria. Only 31.3% of IGT subjects remained as IFG and 62.1% were reclassified as NFG. Similarly, 69.4% of IFG subjects were NGT by WHO criteria. The agreement between the two criteria was poor (K = 0.31). Discordant diabetes groups had higher WHR, systolic and diastolic blood pressure, cholesterol and triglyceride levels than concordant non-diabetes group. Non-diabetes(WHO)/diabetes(ADA) group had higher WHR than diabetes (WHO)/non-diabetes(ADA) group. There were no differences in other metabolic characteristics between the two discordant diabetes groups. IGT/NFG and NGT/IFG group showed higher BMI, WHR, systolic and diastolic blood pressure, cholesterol and triglyceride levels than NGT/NFG group. Metabolic characteristics of IGT/NFG group were not different from those of NGT/IFG group except IGT/NFG subjects were older than NGT/IFG subjects.

CONCLUSION

The agreement between WHO and ADA fasting criteria was poor. ADA fasting criteria can detect new diabetic patients and subjects with impaired glucose metabolism who are not classified as diabetes or IGT by WHO criteria. However, a substantial number of subjects, who may have increased cardiovascular risk and/or increased risk for the development of diabetes and its complication, will be missed when using ADA fasting criteria.

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.

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.