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Tolerance Testing (tolerance + testing)
Kinds of Tolerance Testing Selected AbstractsScreening and diagnosis of prediabetes: where are we headed?DIABETES OBESITY & METABOLISM, Issue 2007K. G. M. M. Alberti It is currently estimated that more than 300 million people have impaired glucose tolerance (IGT), putting them at increased risk for type 2 diabetes mellitus (T2DM) and its adverse consequences. In addition, many others are at risk on the basis of a family history of T2DM, obesity, dyslipidaemia and hypertension. Screening for risk should include both blood glucose testing in high-risk populations and prescreening (e.g. by questionnaire, waist circumference measurement) to identify high-risk individuals in overall low-risk populations; these individuals should then undergo glucose testing. Fasting plasma glucose measurement cannot diagnose IGT; the preferred definite test for diagnosis is oral glucose tolerance testing. [source] Post-challenge glucose predicts coronary atherosclerotic progression in non-diabetic, post-menopausal women,DIABETIC MEDICINE, Issue 10 2007P. B. Mellen Abstract Aims, We sought to determine whether fasting or post-challenge glucose were associated with progression of coronary atherosclerosis in non-diabetic women. Methods, We performed a post-hoc analysis of 132 non-diabetic women who underwent 75-g oral glucose tolerance testing. The primary outcome of interest was progression of atherosclerosis determined by baseline and follow-up coronary angiography, a mean of 3.1 ± 0.9 years apart. We analysed the association of change in minimal vessel diameter (,MD) by quartile of fasting and post-challenge glucose using mixed models that included adjustment for age, systolic blood pressure, total : high-density lipoprotein cholesterol ratio, current smoking, lipid-lowering and anti-hypertensive medication use and other covariates. Results, At baseline, participants had a mean age of 65.7 ± 6.7 years and a mean body mass index of 27.9 ± 8.5 kg/m2. Although there were no significant differences in atherosclerotic progression by fasting glucose category (P for trend across quartiles = 0.99), there was a significant inverse association between post-challenge glucose and ,MD (in mm) (Q1 : 0.01 ± 0.03; Q2 : 0.08 ± 0.03; Q3 : 0.13 ± 0.03; Q4 : 0.11 ± 0.03; P for trend = 0.02). Conclusions, In post-menopausal women without diabetes, post-challenge glucose predicts angiographic disease progression. These findings suggest that even modest post-challenge hyperglycaemia influences the pathogenesis of atherosclerotic progression. [source] Screening for diabetes in Indigenous populations using glycated haemoglobin: sensitivity, specificity, post-test likelihood and risk of diseaseDIABETIC MEDICINE, Issue 7 2005K. G. Rowley Abstract Aims Screening for diabetes using glycated haemoglobin (HbA1c) offers potential advantages over fasting glucose or oral glucose tolerance testing. Current recommendations advise against the use of HbA1c for screening but test properties may vary systematically across populations, according to the diabetes prevalence and risk. We aimed to: (i) characterize the properties of test cut-offs of HbA1c for diagnosis of diabetes relative to a diagnosis based on a fasting plasma glucose concentration of 7.0 mmol/l for high-risk Indigenous populations; and (ii) examine test properties across a range of diabetes prevalence from 5 to 30%. Methods Data were collected from Aboriginal and Torres Strait Islander communities in Australia and a Canadian First Nations community (diabetes prevalence 12,22%) in the course of diabetes diagnostic and risk factor screening programmes (n = 431). Screening test properties were analyzed for the range of HbA1c observed (3,12.9%). Results In separate and pooled analyses, a HbA1c cut point of 7.0% proved the optimal limit for classifying diabetes, with summary analysis results of sensitivity = 73 (56,86)%, specificity = 98 (96,99)%, overall agreement (Youden's index) = 0.71, and positive predictive value (for an overall prevalence of 18%) = 88%. For diabetes prevalence from 5 to 30% the post-test likelihood of having diabetes given HbA1c = 7.0% (positive predictive value) ranged from 62.7 to 93.2%; for HbA1c < 7.0%, the post-test likelihood of having diabetes ranged from 4.5 to 27.7%. Conclusions The results converge with research on the likelihood of diabetes complications in supporting a HbA1c cut-off of 7.0% in screening for diabetes in epidemiological research. Glycated haemoglobin has potential utility in screening for diabetes in high-risk populations. [source] Association between Endothelial Function and Chronotropic Incompetence in Subjects with Chronic Heart Failure Receiving Optimal Medical TherapyECHOCARDIOGRAPHY, Issue 3 2010M.D., Timothy J. Vittorio M.S. Objective: Impairment of flow-mediated, endothelium-dependent vasodilatation (FMD) of the brachial artery identifies peripheral endothelial dysfunction in subjects with chronic congestive heart failure (CHF) and is associated with increased morbidity and mortality. To further elucidate the interaction of peripheral and central mechanisms in the syndrome of CHF, we examined the association between endothelial function and chronotropic incompetence, an emerging prognostic marker in CHF. Methods: Thirty subjects with stable New York Heart Association (NYHA) functional class II,III CHF were studied. A vascular ultrasound study was performed to measure brachial artery FMD. The percentage of age-adjusted maximal predicted heart rate (MPHR) reached during cardiopulmonary exercise tolerance testing (CPETT) was used to assess the degree of chronotropic competence. All patients received ACE inhibitors and ,-adrenoceptor blockers. Results: Brachial artery FMD averaged 1.3 ± 2.4% and age-adjusted % MPHR 74.1 ± 11.7%. FMD correlated with % MPHR among all patients (r = 0.60, P = 0.01). FMD and resting heart rate (RHR) did not significantly correlate (r = 0.13, P = 0.55). Conclusions: FMD, a measure of peripheral endothelial dysfunction, and % MPHR, a central determinant of cardiac output, are moderately correlated in heart failure patients receiving optimal medical therapy. Whether a cause-effect relationship underlies this association remains to be investigated. (Echocardiography 2010;27:294-299) [source] Original Paper: Telmisartan Effects on Insulin Resistance in Obese or Overweight Adults Without Diabetes or HypertensionJOURNAL OF CLINICAL HYPERTENSION, Issue 9 2010Willa Hsueh MD J Clin Hypertens (Greenwich). 2010;12:746,752. ©2010 Wiley Periodicals, Inc. Angiotensin receptor blockers (ARBs) are antihypertensive agents associated with reduced risk of new-onset diabetes mellitus. The ARB telmisartan is a partial agonist of peroxisome proliferator,activated receptor-gamma (PPAR-,). This study evaluated the effect of telmisartan on insulin resistance, a known target of PPAR-, agonism. Overweight/obese persons with body mass index ,28 kg/m2, waist circumference ,35 inches, and components of the metabolic syndrome without hypertension or diabetes who were not preselected for insulin resistance were enrolled. Patients were randomized to telmisartan or matching placebo for 16 weeks. The primary efficacy measure was changed from baseline in the insulin sensitivity index (SI), calculated from oral glucose tolerance testing. SI was also evaluated in a subset of patients using a hyperinsulinemic euglycemic clamp. Secondary end points included measures of insulin sensitivity and glucose and lipid metabolism. A total of 138 patients were randomized and received ,1 dose of study medication; 128 completed the study. At end point, no significant difference was found between telmisartan and placebo groups regarding change from baseline in SI or in glucose area under the curve. No significant between-group differences were found regarding glucose metabolism or lipoprotein levels. In the population with abdominal obesity and components of the metabolic syndrome, telmisartan did not increase insulin sensitivity. [source] Doppler sonographic characteristics of umbilical and uterine arteries during oral glucose tolerance testing in healthy pregnant womenJOURNAL OF CLINICAL ULTRASOUND, Issue 9 2003Yariv Yogev MD Abstract Purpose Studies have shown that maternal hyperglycemia may be associated with increased placental resistance to blood flow and possibly adverse perinatal outcomes. The aim of this study was to determine whether Doppler velocimetric dynamics change in the uterine and umbilical arteries in healthy pregnant women (without gestational diabetes) during acute hyperglycemia induced by oral glucose tolerance testing. Methods Flow in the umbilical and right and left uterine arteries was assessed by spectral Doppler sonographic examination of healthy pregnant women at 24,28 weeks' menstrual age. Four Doppler studies were conducted for each woman: 1 before oral administration of 100 g of glucose and 3 more at 1, 2, and 3 hours after glucose administration. The systolic-to-diastolic ratio was calculated for the umbilical artery, and the resistance index was calculated separately for the left and right uterine arteries. Results All results of oral glucose tolerance testing were normal, and Doppler signals were obtained in all 30 patients enrolled. No abnormal systolic-to-diastolic ratios or resistance indices were detected in any of the examinations. No significant differences in waveforms or resistance indices between the right and left uterine arteries were found during the various testing intervals. Conclusions Acute hyperglycemia induced in healthy pregnant women does not affect blood flow velocimetric characteristics in the umbilical or uterine arteries at any stage of oral glucose tolerance testing. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:461,464, 2003 [source] Interaction of the common apolipoprotein C-III (APOC3 -482C > T) and hepatic lipase (LIPC -514C > T) promoter variants affects glucose tolerance in young adults.ANNALS OF HUMAN GENETICS, Issue 3 2001European Atherosclerosis Research Study II (EARS-II) Both hepatic lipase (HL) and apolipoprotein C-III (apoC-III) influence lipid metabolism. Common variation in promoters of both genes, LIPC -514C > T and APOC3 -482C > T, respectively, have been shown to affect plasma lipids and lipoproteins and glucose tolerance. We studied the interaction between both variants on parameters of glucose tolerance and lipid metabolism in 714 healthy young males participating in the second European Atherosclerosis Research Study (EARS-II). Approximately 18% of the subjects were carriers of at least one rare LIPC and APOC3 allele. These subjects exhibited, after fasting and oral fat loading, the highest values of triglyceride-rich lipoproteins, but there was no significant interactive effect on any lipid variable. However, interaction occurred on basal diastolic blood pressure (p=0.036) and, during oral glucose tolerance testing, on peak (p= 0.0065) and area under the curve for glucose (p=0.049), and insulin (p= 0.035). This resulted in the highest diastolic blood pressure and lowest glucose tolerance in carriers of at least one rare allele of both genes. Thus gene:gene interaction between LIPC and APOC3, even in these healthy young males, leads to changes in parameters that are typically characteristic of Syndrome-X. [source] | ||||||||||||||||||||||