Robyn J. Tapp

Relation between fasting glucose and retinopathy for diagnosis of diabetes: three population-based cross-sectional studies.

BACKGROUND The WHO and American Diabetes Association criteria for diagnosing diabetes mellitus assume the presence of a glycaemic threshold with high sensitivity for identifying retinopathy. However, this assumption is based on data from three previous studies that had important limitations in detecting retinopathy. We aimed to provide updated data for the relation between fasting plasma glucose (FPG) and retinopathy, and to assess the diagnostic accuracy of current FPG thresholds in identifying both prevalent and incident retinopathy. METHODS We examined the data from three cross-sectional adult populations: those in the Blue Mountains Eye Study (BMES, Australia, n=3162), the Australian Diabetes, Obesity and Lifestyle Study (AusDiab, Australia, n=2182), and the Multi-Ethnic Study of Atherosclerosis (MESA, USA, n=6079). Retinopathy was diagnosed from multiple retinal photographs of each eye, and graded according to the modified Airlie House Classification system. Plasma glucose concentrations were measured from fasting venous blood samples. FINDINGS The overall prevalence of retinopathy was 11.5% in BMES (95% CI 10.4-12.6%), 9.6% in AusDiab (8.4-10.9), and 15.8% in MESA (14.9-16.7). However, we found inconsistent evidence of a uniform glycaemic threshold for prevalent and incident retinopathy, with analyses suggesting a continuous relation. The widely used diabetes FPG cutoff of 7.0 mmol/L or higher had sensitivity less than 40% (range 14.8-39.1) for detecting retinopathy, with specificity between 80.8% and 95.8%. The area under receiver operating characteristic curves for FPG and retinopathy was low and ranged from 0.56 to 0.61. INTERPRETATION We saw no evidence of a clear and consistent glycaemic threshold for the presence or incidence of retinopathy across different populations. The current FPG cutoff of 7.0 mmol/L used to diagnose diabetes did not accurately identify people with and without retinopathy. These findings suggest that the criteria for diagnosing diabetes could need reassessment.

Glucose indices, health behaviors, and incidence of diabetes in Australia: The Australian diabetes, obesity and lifestyle study

OBJECTIVE—This national, population-based study reports diabetes incidence based on oral glucose tolerance tests (OGTTs) and identifies risk factors for diabetes in Australians. RESEARCH DESIGN AND METHODS—The Australian Diabetes, Obesity and Lifestyle Study followed-up 5,842 participants over 5 years. Normal glycemia, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes were defined using World Health Organization criteria. RESULTS—Age-standardized annual incidence of diabetes for men and women was 0.8% (95% CI 0.6–0.9) and 0.7% (0.5–0.8), respectively. The annual incidence was 0.2% (0.2–0.3), 2.6% (1.8–3.4), and 3.5% (2.9–4.2) among those with normal glycemia, IFG, and IGT, respectively, at baseline. Among those with IFG, the incidence was significantly higher in women (4.0 vs. 2.0%), while among those with IGT, it was significantly higher in men (4.4 vs. 2.9%). Using multivariate logistic regression, hypertension (odds ratio 1.64 [95% CI 1.17–2.28]), hypertriglyceridemia (1.46 [1.05–2.02]), log fasting plasma glucose (odds ratio per 1 SD 5.25 [95% CI 3.98–6.92]), waist circumference (1.26 [1.08–1.48]), smoking (1.70 [96% CI 1.11–2.63]), physical inactivity (1.56 [1.12–2.16]), family history of diabetes (1.82 [1.30–2.52]), and low education level (1.85 [1.04–3.31]) were associated with incident diabetes. In age- and sex-adjusted models, A1C was a predictor of diabetes in the whole population, in those with normal glycemia, and in those with IGT or IFG. CONCLUSIONS—Diabetes incidence is 10–20 times greater in those with IGT or IFG than those with normal glycemia. Measures of glycemia, A1C, metabolic syndrome components, education level, smoking, and physical inactivity are risk factors for diabetes.

Glucose indices, health behaviours and incidence of diabetes in Australia: the AusDiab study.

OBJECTIVE—This national, population-based study reports diabetes incidence based on oral glucose tolerance tests (OGTTs) and identifies risk factors for diabetes in Australians. RESEARCH DESIGN AND METHODS—The Australian Diabetes, Obesity and Lifestyle Study followed-up 5,842 participants over 5 years. Normal glycemia, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes were defined using World Health Organization criteria. RESULTS—Age-standardized annual incidence of diabetes for men and women was 0.8% (95% CI 0.6–0.9) and 0.7% (0.5–0.8), respectively. The annual incidence was 0.2% (0.2–0.3), 2.6% (1.8–3.4), and 3.5% (2.9–4.2) among those with normal glycemia, IFG, and IGT, respectively, at baseline. Among those with IFG, the incidence was significantly higher in women (4.0 vs. 2.0%), while among those with IGT, it was significantly higher in men (4.4 vs. 2.9%). Using multivariate logistic regression, hypertension (odds ratio 1.64 [95% CI 1.17–2.28]), hypertriglyceridemia (1.46 [1.05–2.02]), log fasting plasma glucose (odds ratio per 1 SD 5.25 [95% CI 3.98–6.92]), waist circumference (1.26 [1.08–1.48]), smoking (1.70 [96% CI 1.11–2.63]), physical inactivity (1.56 [1.12–2.16]), family history of diabetes (1.82 [1.30–2.52]), and low education level (1.85 [1.04–3.31]) were associated with incident diabetes. In age- and sex-adjusted models, A1C was a predictor of diabetes in the whole population, in those with normal glycemia, and in those with IGT or IFG. CONCLUSIONS—Diabetes incidence is 10–20 times greater in those with IGT or IFG than those with normal glycemia. Measures of glycemia, A1C, metabolic syndrome components, education level, smoking, and physical inactivity are risk factors for diabetes.

Foot complications in Type 2 diabetes: an Australian population‐based study

Aims  To determine the prevalence and risk factors for neuropathy and peripheral vascular disease (PVD) in the Australian diabetic population and identify those at high risk of foot ulceration.

Longitudinal Association of Glucose Metabolism With Retinopathy: Results from the Australian Diabetes Obesity and Lifestyle (AusDiab) study

OBJECTIVE—We determined the longitudinal association of glucose metabolism with retinopathy in a sample of the Australian population. RESEARCH DESIGN AND METHODS—The Australian Diabetes Obesity and Lifestyle (AusDiab) study is a national, longitudinal study of adults aged ≥25 years from 42 randomly selected areas of Australia. Retinopathy was assessed at baseline in 1999–2000 and 5 years later in 2004–2005 in participants identified as having diabetes (based on self-report and oral glucose tolerance test) and impaired glucose metabolism and in a random sample with normal glucose tolerance. Complete retinal data were available for 1,192 participants. Photographs were graded at two time points according to a simplified version of the Wisconsin grading system. RESULTS—The 5-year incidences of retinopathy were 13.9 and 3.0% among those with known and newly diagnosed diabetes at baseline, respectively. Of those who developed incident newly diagnosed diabetes at follow-up, 11.9% had retinopathy at baseline compared with 5.6% of those who did not progress to incident newly diagnosed diabetes (P = 0.037). After adjustment for factors identified as risk factors for diabetes, individuals with retinopathy signs at baseline were twice as likely to develop incident newly diagnosed diabetes compared with those who did not have retinopathy signs at baseline. CONCLUSIONS—The 5-year incidence of retinopathy was 13.9% among individuals with known diabetes. Nondiabetic individuals with retinopathy signs at baseline had a twofold higher risk of developing incident newly diagnosed diabetes 5 years later. This result provides further evidence that mild retinopathy signs may be a preclinical marker of underlying microvascular disease and future diabetes risk.

Retinal Arteriolar Caliber Predicts Incident Retinopathy: The Australian Diabetes, Obesity and Lifestyle (AusDiab) Study

Changes in retinal vascular caliber may reflect subclinical microvascular disease and provide prognostic information regarding risk of retinopathy. In this study, we examined the prospective association of retinal vascular caliber with retinopathy risk in an Australian population-based cohort. A total of 906 participants without retinopathy at baseline had retinal vascular caliber measured from photographs and were followed-up for 5 years for incident retinopathy. After adjusting for age, sex, systolic blood pressure, A1C, and other risk factors, individuals with wider retinal arteriolar caliber (widest 25% vs. the remaining three-quarters of the population) were more likely to develop incident retinopathy (odds ratio 4.79 [95% CI 1.57–14.58]). This association was not significant in individuals without diabetes. Venular caliber did not predict incident retinopathy. Our findings suggest that retinal arteriolar dilatation is a specific sign of diabetic microvascular dysfunction and may be a preclinical marker of diabetic retinopathy.

Prevention of Type 2 Diabetes and Its Complications in Developing Countries: A Review

BackgroundType 2 diabetes mellitus (T2DM) is a significant global public health problem affecting more than 285 million people worldwide. Over 70% of those with T2DM live in developing countries, and this proportion is increasing annually. Evidence suggests that lifestyle and other nonpharmacological interventions can delay and even prevent the development of T2DM and its complications; however, to date, programs that have been specifically adapted to the needs and circumstances of developing countries have not been well developed or evaluated.PurposeThe purpose of this article is to review published studies that evaluate lifestyle and other non-pharmacological interventions aimed at preventing T2DM and its complications in developing countries.MethodsWe undertook an electronic search of MEDLINE, PubMed, and EMBASE with the English language restriction and published until 30 September 2009.ResultsNine relevant publications from seven studies were identified. The reported interventions predominantly used counseling and educational methods to improve diet and physical activity levels. Each intervention was found to be effective in reducing the risk of developing T2DM in people with impaired glucose tolerance, and improving glycemic control in people with T2DM.ConclusionsThe current evidence concerning the prevention of T2DM and its complications in developing countries has shown reasonably consistent and positive results; however, the small number of studies creates some significant limitations. More research is needed to evaluate the benefits of low-cost screening tools, as well as the efficacy, cost-effectiveness, and sustainability of culturally appropriate interventions in such countries.

Recommendations on the Use of Echocardiography in Adult Hypertension: A Report from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE)†

Hypertension remains a major contributor to the global burden of disease. The measurement of blood pressure continues to have pitfalls related to both physiological aspects and acute variation. As the left ventricle (LV) remains one of the main target organs of hypertension, and echocardiographic measures of structure and function carry prognostic information in this setting, the development of a consensus position on the use of echocardiography in this setting is important. Recent developments in the assessment of LV hypertrophy and LV systolic and diastolic function have prompted the preparation of this document. The focus of this work is on the cardiovascular responses to hypertension rather than the diagnosis of secondary hypertension. Sections address the pathophysiology of the cardiac and vascular responses to hypertension, measurement of LV mass, geometry, and function, as well as effects of treatment.

Wave Reflection Predicts Cardiovascular Events in Hypertensive Individuals Independent of Blood Pressure and Other Cardiovascular Risk Factors An ASCOT (Anglo-Scandinavian Cardiac Outcome Trial) Substudy

OBJECTIVES This study investigated whether wave reflection measured by wave intensity analysis predicts future cardiovascular events in individuals with hypertension and sought to establish whether this relationship is independent of other cardiovascular risk factors and is associated with evidence of increased load on the left ventricle. BACKGROUND Wave reflection may impose an additional load on the left ventricle, and augmentation index, a surrogate of wave reflection, has been reported to predict cardiovascular events in some, but not all studies. METHODS Measurements of brachial and carotid blood pressure (BP) measurement, carotid ultrasound, echocardiography, and blood chemistry analyses were performed on 259 ASCOT (Anglo Scandinavian Cardiac Outcomes Trial) participants approximately 1 year after randomization, and wave intensity analysis was used to calculate wave reflection index (WRI), the ratio of peak forward to peak backward pressure (P(b)/P(f)), and carotid augmentation index (cAI(x)). All participants were followed up for a median period of 5.9 years, accruing 33 cardiovascular events. RESULTS WRI, P(b)/P(f), and to a lesser extent, cAI(x), were correlated. WRI predicted cardiovascular events (hazard ratio: 2.10; 95% confidence interval: 1.10 to 3.99; p = 0.02) in an unadjusted model. Multivariate analysis showed that this association was independent of BP. P(b)/P(f) and cAI(x) did not significantly predict cardiovascular events. WRI was also positively associated with increased left ventricular mass index and elevated B-type natriuretic peptide adjusted for age and sex, and these associations were independent of BP or other cardiovascular risk factors. CONCLUSIONS Higher wave reflection predicts future cardiovascular events independent of conventional risk factors in people with treated hypertension.

Impact of Size at Birth on the Microvasculature: The Avon Longitudinal Study of Parents and Children

BACKGROUND. The impact of early life factors on the microvasculature is relatively unknown. OBJECTIVES. We hypothesized that small birth size may be associated with structural variations in the retinal vasculature in children. METHODS. The Avon Longitudinal Study of Parents and Children followed a cohort of children born in 1991–1992 from birth. The current study included the first 263 children who were systematically screened in the year-12 follow-up. Complete data were available for 166 children with a gestation of ≥37 weeks. Retinal circulatory measures were evaluated, including retinal microvascular tortuosity and bifurcation optimality deviance, an indicator of abnormal endothelial function. RESULTS. Optimality deviance and retinal tortuosity were higher among those with lower birth weight. Linear regression modeling was used to assess the association of retinal microvascular measures with birth weight. The standardized β coefficient between optimality deviance and birth weight was −.182 adjusted for gender and age in weeks; additional adjustment for systolic blood pressure and heart rate had little impact on the β coefficient. A similar association was observed for retinal tortuosity. CONCLUSION. The findings of this study suggest that early life factors may have an important impact on retinal vascular structure, possibly through an adverse effect on endothelial function.