Screening with HbA1c identifies only one in two individuals with diagnosis of prediabetes at oral glucose tolerance test: findings in a real-world Caucasian population

Patient- and Physician-Level Factors Associated With Adherence to C-CHANGE Recommendations in Primary Care Settings in Ontario

BACKGROUND

We previously found large variation among family physicians in adherence to the Canadian Cardiovascular Harmonization of National Guidelines Endeavour (C-CHANGE). We assessed the role of patient- and physician-level factors in the variation in adherence to recommendations for managing cardiovascular disease risk factors.

METHODS

We conducted a retrospective study using multilevel logistic regression analyses with the Electronic Medical Record Administrative data Linked Database (EMRALD) housed at ICES in Ontario. Five quality indicators based on C-CHANGE guidelines were modelled. Effects of clustering and between-group variation, patient-level (sociodemographics, comorbidities) and physician-level characteristics (demographic and practice information) were assessed to determine odds ratios of receiving C-CHANGE recommended care.

RESULTS

In all, 324 Ontario physicians practicing in 41 clinics who provided care to 227,999 adult patients were studied. We found significant variation in quality indicators, with 15% to 39% of the total variation attributable to nonpatient factors. The largest variation was in performing 2-hour plasma glucose testing in prediabetic patients. Patient-level factors most frequently associated with recommendation adherence included sex, age, and multi-comorbidities. Women were more likely than men to have their body mass index measured, and their blood pressure controlled, but less likely to receive antiplatelet medications and liver-enzyme testing if overweight or obese.

CONCLUSIONS

The majority of variations in adherence were attributable to patient attributes, but a substantial proportion of unexplained variation was due to differences among physicians and clinics. This finding may signal suboptimal processes or structures and warrant further investigation to improve the quality of primary care management of cardiovascular disease in Ontario.

Impaired Glucose Tolerance in Adults with Duchenne and Becker Muscular Dystrophy

The aim of this study was to determine the response to an oral glucose tolerance test (OGTT) in adult males with Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD), and to investigate whether body composition contributes to any variance in the glucose response. Twenty-eight adult males with dystrophinopathy (BMD, n = 13; DMD, n = 15) and 12 non-dystrophic controls, ingested 75 g oral anhydrous glucose solution. Fingertip capillary samples were assessed for glucose at 30-min intervals over 2-h post glucose ingestion. Fat free mass relative to body mass (FFM/BM) and body fat (BF%) was assessed using bioelectrical impedance. Vastus lateralis muscle anatomical cross sectional area (VL ACSA) was measured using B-mode ultrasonography. Blood glucose was higher in MD groups than control at 60, 90 and 120 min post ingestion of glucose. Compared to controls, FFM/BM and VL ACSA were lower in MD groups compared to controls (p < 0.001). Glucose tolerance values at 120 min were correlated with FFM/BM and BF% in the BMD group only. Our results suggest that glucose tolerance is impaired following OGTT in adult males with BMD and DMD. It is recommended that adults with BMD and DMD undertake routine glucose tolerance assessments to allow early detection of impaired glucose tolerance.

Prevalence of moderately increased albuminuria among individuals with normal HbA1c level but impaired glucose tolerance: Results from the LIFE-Adult-Study

AIMS

Diabetes screening strategies using glycated haemoglobin (HbA1c) as first-instance diagnostic parameter may cause failure to detect individuals with abnormal glucose regulation and possible signs of microvascular complications despite "rule-out" HbA1c levels. This cross-sectional study examined the diagnostic performance of HbA1c in relation to fasting and two-hour postload plasma glucose (FPG/2 h-PG), and investigated whether individuals with normal HbA1c but abnormal FPG/2 h-PG have a higher prevalence of moderately increased albuminuria as possible sign of early stage kidney damage.

METHODS

A total of 2695 individuals (age 40-79 years, 48% men) without prior diagnosis of diabetes and complete measurement of HbA1c, FPG, 2 h-PG and urine albumin-creatinine ratio (UACR) were taken from a large population-based epidemiological study in the City of Leipzig, Germany.

RESULTS

A total of 2439 individuals (90.5%, 95% CI: 89.4-91.6) had normal HbA1c levels, <39 mmol/mol (<5.7%), while 234 (8.7%, 95% CI: 7.7-9.8) had prediabetes, HbA1c ≥39 and <48 mmol/mol (≥5.7 and <6.5%), and 22 (0.8%, 95% CI: 0.5-1.2) had diabetes, HbA1c ≥48 mmol/mol (≥6.5%), according to HbA1c. Among individuals with normal HbA1c, 35.6% (95% CI: 33.7-37.5) had impaired fasting glucose or impaired glucose tolerance and 1.8% (95% CI: 1.4-2.4) had diabetes according to FPG/2 h-PG. Individuals with normal HbA1c but prediabetic or diabetic FPG/2 h-PG had a significantly higher prevalence of moderately increased albuminuria (9.4%, 95% CI: 7.6-11.5 and 13.3%, 95% CI: 5.8-25.4, respectively) than individuals with normal HbA1c and normal FPG/2 h-PG (3.9%, 95% CI: 3.0-5.0).

CONCLUSIONS

The prevalence of prediabetes according to FPG/2 h-PG among individuals with normal HbA1c is considerably high, and the prevalence of moderately increased albuminuria in this group is significantly elevated. Risk factors for diabetes such as age, gender and BMI may help to better identify this at-risk group.

Significance of prediabetes as a nosological entity

Prediabetes is a glucose metabolism disorder considered as a distinct nosological entity which strongly predicts the development of type 2 diabetes mellitus. This nosological entity itself is a serious condition indicating an increased risk of atherosclerotic and oncological complications. In patients with prediabetes, other components of metabolic syndrome are usually present, such as arterial hypertension, obesity or dyslipidaemia, further increasing an individual's risk of morbidity and mortality. Prediabetes is a long-developing disorder which offers enough time for early diagnosis and intervention; it may even be reversible. This review summarizes current knowledge on the definition, detection, epidemiology, cardiovascular and other consequences of prediabetes. It also gives suggestions for future research, along with recommendations for clinical practice.

HbA1c Cutoff Point of 5.9% Better Identifies High Risk of Progression to Diabetes among Chinese Adults: Results from a Retrospective Cohort Study

AIMS

This article performed a retrospective cohort study to estimate the annual incidence rates of diabetes and to assess the utility of HbA1c as a predictor for progression to diabetes in Chinese community adults aged 40 years or older.

METHODS

In all, 2778 nondiabetic subjects (including 1901 women) underwent HbA1c testing and oral glucose tolerance test (OGTT) measurements at baseline and after 3 years. Diabetes and prediabetes were defined using the WHO criteria. The HbA1c cutoff points were evaluated to predict the future risks of diabetes. Relative risk (RR) was calculated using the chi-square test. The area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the predictive efficiency of fasting plasma glucose (FPG), 2 hr postprandial plasma glucose (2hPG), and HbA1c for progression to diabetes. A superior cutoff point was defined as the point on the ROC curve with a larger Youden index.

RESULTS

Overall, 7.5% (210/2778) of the subjects progressed to diabetes, yielding an annual 2.5% diabetes incidence rate. Additionally, 4.5% (100/2227) of the subjects with normal glucose tolerance (NGT) and 19.6% (110/561) of the subjects with prediabetes progressed to diabetes, and the relative risk of progression to diabetes was 5.188 times higher in subjects with prediabetes than in subjects with NGT (p < 0.001). Compared to subjects with HbA1c values ≤ 5.6%, the RRs of progression to diabetes in subjects whose HbA1c ranged from 5.7 to 5.8%, 5.9 to 6.2%, 6.3 to 6.4%, and ≥6.5% were 1.165, 2.582, 5.732, and 16.619, respectively. However, the RRs for subjects with HbA1c ranging from 5.7 to 5.8% and those with HbA1c ≤ 5.6% did not differ significantly (p = 0.615). The AUCs for predicting diabetes after 3 years by FPG, 2hPG, and HbA1c were 0.752 (95% confidence interval 0.718-0.787), 0.710 (95% confidence interval 0.671-0.748), and 0.756 (95% confidence interval 0.720-0.793), respectively. The HbA1c cutoff point of 5.9% (sensitivity of 0.771 and specificity of 0.580) may better identify individuals at high risk of progression to diabetes than the 5.7% value (sensitivity of 0.862 and specificity of 0.371) due to the former's larger Youden index of 0.351, which exceeded the indices for FPG and 2hPG.

CONCLUSIONS

The use of HbA1c values ≥ 5.9% may provide greater accuracy in evaluating the risk of progression to diabetes and identify individuals with prediabetes with greater reliability among Chinese adults.

Diabetic by HbA1c, Normal by OGTT: A Frequent Finding in the Mexico City Diabetes Study

CONTEXT

The agreement between glucose-based and hemoglobin A1c (HbA1c)-based American Diabetes Association criteria in the diagnosis of normal glucose tolerance, prediabetes, or diabetes is under scrutiny. A need to explore the issue among different populations exists.

OBJECTIVE

Examine the results obtained with both methods in the diagnosis of the glycemic status.

DESIGN

The Mexico City Diabetes Study is a population-based, prospective investigation.

SETTING

Low-income elder urban community.

PARTICIPANTS

All 854 participants without known diabetes had both oral glucose tolerance test (OGTT) and HbA1c measurements on the same day of the 2008 phase.

INTERVENTIONS

Standardized protocol: questionnaires, anthropometry, and biomarkers.

MAIN OUTCOME

Diagnostic classification of American Diabetes Association criteria.

RESULTS

We found by OGTT normal glucose tolerance (NGT) in 512 (59.9%) participants, prediabetes [impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT)] in 261 (30.5%), and diabetes in 81 (9.4%). In total, 232 in the NGT group (45.3%) and 158 in the prediabetes group (60.5%) had HbA1c ≥6.5%. Body mass index, waist circumference, and blood pressure were significantly different among OGTT-defined diabetic status groups but not in the HbA1c-diagnosed group. We identified 404 participants in the NGT group with confirmed NGT throughout all phases of the Mexico City Diabetes Study. Of these, 184 (45.5%) had HbA1c ≥6.5%. In a vital/diabetes status follow-up performed subsequently, we found that, of these, 133 remained nondiabetic, 3 had prediabetes, 7 had diabetes, and 13 had died without diabetes; we were unable to ascertain the glycemic status in 5 and vital status in 23.

CONCLUSIONS

Normal OGTT coexisting with elevated HbA1c is a common finding in this cohort. It is possible that this finding is not mediated by hyperglycemia. This might occur in similar populations.

Survivors of childhood leukaemia treated with haematopoietic stem cell transplantation and total body irradiation should undergo screening for diabetes by oral glucose tolerance tests

AIMS

Childhood cancer survivors treated with haematopoietic stem cell transplantation (HSCT) and total body irradiation are at an increased risk of developing diabetes early in life due to insulin resistance and β-cell dysfunction, but the optimal screening method is unknown. The National Institute for Health and Care Excellence guidelines for community diabetes screening recommend using fasting glucose ≥ 7 mmol/l and/or HbA1c ≥ 48 mmol/mol (6.5%) for diagnosis and, fasting glucose 5.5-6.9 mmol/l or HbA1c 42-47 mmol/mol (6-6.5%) to indicate high risk. This study aimed to evaluate the sensitivities of fasting glucose and HbA1c in the diagnosis of diabetes and impaired glucose tolerance in childhood HSCT survivors.

METHOD

The patients were 35 (male = 19) HSCT survivors from a single UK centre under follow-up from 2006 to 2013. Patients had a median age (range) of 19.2 (13.1-26.2) years and had been treated for acute lymphoblastic (n = 31) or myeloid (n = 4) leukaemia when aged 7.8 (2.4-16.7) years. The outcome measures were oral glucose tolerance test (OGTT), fasting glucose and HbA1c .

RESULTS

OGTT identified 6 patients with diabetes (120-min glucose ≥ 11.1 mmol/l), 12 with impaired glucose tolerance (120-min glucose 7.8-11.0 mmol/l) and 2 with impaired fasting glucose (≥ 7 mmol/l). Fasting glucose ≥ 7 mmol/l or HbA1c ≥ 48 mmol/mol identified two of the six patients with diabetes diagnosed on OGTT. Fasting glucose ≥ 5.5 mmol/l and HbA1c ≥ 42 mmol/mol identified three and two patients, respectively, with diabetes. Only 1 of 12 patients with impaired glucose tolerance had a fasting glucose ≥ 5.5 mmol/l and none had HbA1c ≥ 42 mmol/mol (≥ 6%).

CONCLUSIONS

The fasting glucose and HbA1c cut-offs used in UK population screening only identified one-third of HSCT survivors with diabetes and do not identify those at risk. Diabetes screening in HSCT survivors requires standard OGTTs.

Jicama (Pachyrhizus erosus) extract increases insulin sensitivity and regulates hepatic glucose in C57BL/Ksj-db/db mice

This study investigated the effect of jicama extract on hyperglycemia and insulin sensitivity in an animal model of type 2 diabetes. Male C57BL/Ksj-db/db mice were divided into groups subsequently fed a regular diet (controls), or diet supplemented with jicama extract, and rosiglitazone. After 6 weeks, blood levels of glucose and glycosylated hemoglobin were significantly lower in animals administered the jicama extract than the control group. Additionally, glucose and insulin tolerance tests showed that jicama extract increased insulin sensitivity. The homeostatic index of insulin resistance was lower in the jicama extract-treated group than in the diabetic control group. Administration of jicama extract significantly enhanced the expressions of the phosphorylated AMP-activated protein kinase and Akt substrate of 160 kDa, and plasma membrane glucose transporter type 4 in skeletal muscle. Jicama extract administration also decreased the expressions of glucose 6-phosphatase and phosphoenol pyruvate carboxykinase in the liver. Jicama extract may increases insulin sensitivity and inhibites the gluconeogenesis in the liver.