Comparison of fasting and 2-hour glucose and HbA1c levels for diagnosing diabetes. Diagnostic criteria and performance revisited

Comparative analysis of hemodialysis and peritoneal dialysis on the risk of new onset diabetes mellitus

BACKGROUND

Diabetes mellitus is a significant risk factor for cardiovascular events and mortality in dialysis patients. The impact of different dialysis modalities on the risk of new onset diabetes mellitus (NODM) remains a subject of debate. Previous studies did not adequately account for critical confounding factors such as pre-dialysis glycemic status, medication use, and nutritional status, which may influence the association between dialysis modality and NODM risk.

METHODS

We conducted a retrospective cohort study of 1426 non-diabetic end-stage renal disease (ESRD) patients who underwent either hemodialysis (HD) or peritoneal dialysis (PD) at a single medical center. We used different statistical methods, adjusting for potential confounding factors, and accounted for competing risk of death.

RESULTS

Over 12 years, 331 patients (23 %) developed NODM. After adjusting for potential confounding factors and mortality, PD patients had a significantly higher risk of NODM compared to HD patients (adjusted HR 1.52, p = 0.001). A propensity-matched cohort sensitivity analysis yielded similar results. Among patients with prediabetes, those receiving PD had a 2.93 times higher risk of developing NODM than those receiving HD (p for interaction <0.001), whereas no significant difference was observed among euglycemic patients. NODM was also associated with a 1.78 times increased risk of major cardiovascular events.

CONCLUSION

Our study provides evidence that PD treatment may increase the risk of NODM in ESRD patients, particularly among those with preexisting prediabetes. These findings highlight the importance of personalized treatment approaches, and nephrologists should consider prediabetes when choosing the dialysis modality for their patients.

Using nephropathy as an outcome to determine the HbA1c diagnostic threshold for type 2 diabetes

OBJECTIVE

The hemoglobin A1c (HbA1c) diagnostic threshold for type 2 diabetes (T2D) of 6.5 % (48 mmol/mol) was based on the prevalence of retinopathy found in populations not known to have T2D. It is unclear if nephropathy has a similar HbA1c threshold, partly because it is a rarer complication of early diabetes. This cohort study investigated a very high diabetes prevalence population to determine if a better diagnostic HbA1c value can be established for predicting nephropathy rather than retinopathy in subjects without T2D.

METHODS

The urine albumin:creatinine ratios (UACRs) of 2920 healthy individuals from the Qatar Biobank who had an HbA1c ≥ 5.6 %. were studied. Nephropathy was defined as a UACR≥30 mg/g and its prediction by HbA1c was assessed using cut-points ranging from 5.7 to 7.0 % to dichotomize high from low HbA1c.

RESULTS

Although there was a significant trend for an increased prevalence of abnormal UACR as the HbA1c threshold increased (p < 0.01), significance was due mostly to subjects with HbA1c ≥ 7.0 % (53 mmol/mol). The odds ratios for abnormal UACR were similar over the 5.7-6.9 % HbA1c threshold range, with a narrow odds ratio range of 1.2-1.6. Utilizing area-under-receiver-operating characteristic curves, no HbA1c threshold <7.0 % was identified as the best predictor of nephropathy.

CONCLUSION

Even in a population with a high prevalence of known and unknown diabetes, no HbA1c threshold <7.0 % could be found predicting an increased prevalence of nephropathy. This means there is not a requirement to change the existing retinopathy-based HbA1c threshold of 6.5 % to also accommodate diabetes nephropathy risk.

International Diabetes Federation Position Statement on the 1-hour post-load plasma glucose for the diagnosis of intermediate hyperglycaemia and type 2 diabetes

Many individuals with intermediate hyperglycaemia (IH), including impaired fasting glycaemia (IFG) and impaired glucose tolerance (IGT), as presently defined, will progress to type 2 diabetes (T2D). There is confirmatory evidence that T2D can be prevented by lifestyle modification and/or medications, in people with IGT diagnosed by 2-h plasma glucose (PG) during a 75-gram oral glucose tolerance test (OGTT). Over the last 40 years, a wealth of epidemiological data has confirmed the superior value of 1-h plasma glucose (PG) over fasting PG (FPG), glycated haemoglobin (HbA1c) and 2-h PG in populations of different ethnicity, sex and age in predicting diabetes and associated complications including death. Given the relentlessly rising prevalence of diabetes, a more sensitive, practical method is needed to detect people with IH and T2D for early prevention or treatment in the often lengthy trajectory to T2D and its complications. The International Diabetes Federation (IDF) Position Statement reviews findings that the 1-h post-load PG ≥ 155 mg/dL (8.6 mmol/L) in people with normal glucose tolerance (NGT) during an OGTT is highly predictive for detecting progression to T2D, micro- and macrovascular complications, obstructive sleep apnoea, cystic fibrosis-related diabetes mellitus, metabolic dysfunction-associated steatotic liver disease, and mortality in individuals with risk factors. The 1-h PG of 209 mg/dL (11.6 mmol/L) is also diagnostic of T2D. Importantly, the 1-h PG cut points for diagnosing IH and T2D can be detected earlier than the recommended 2-h PG thresholds. Taken together, the 1-h PG provides an opportunity to avoid misclassification of glycaemic status if FPG or HbA1c alone are used. The 1-h PG also allows early detection of high-risk people for intervention to prevent progression to T2D which will benefit the sizeable and growing population of individuals at increased risk of T2D. Using a 1-h OGTT, subsequent to screening with a non-laboratory diabetes risk tool, and intervening early will favourably impact the global diabetes epidemic. Health services should consider developing a policy for screening for IH based on local human and technical resources. People with a 1-h PG ≥ 155 mg/dL (8.6 mmol/L) are considered to have IH and should be prescribed lifestyle intervention and referred to a diabetes prevention program. People with a 1-h PG ≥ 209 mg/dL (11.6 mmol/L) are considered to have T2D and should have a repeat test to confirm the diagnosis of T2D and then referred for further evaluation and treatment. The substantive data presented in the Position Statement provides strong evidence for redefining current diagnostic criteria for IH and T2D by adding the 1-h PG.

Association and pathways of baseline and longitudinal hemoglobin A1c with the risk of incident stroke: A nationwide prospective cohort study

AIMS

To investigate the association of baseline and long-term mean hemoglobin A1c (HbA1c) with the risk of stroke.

METHODS

A total of 11,220 participants aged over 45 years and without stroke at baseline were enrolled from the China Health and Retirement Longitudinal Study. Mean HbA1c was calculated as the mean of HbA1c at all previous visits before stroke occurred or the end of follow-up. Multivariable-adjusted Cox regressions and Bayesian network were used for the analysis.

RESULTS

During a median follow-up of 7.50 years, a total of 626 cases of stroke occurred. The risk of stroke increased with quintiles of baseline and mean HbA1c, the hazard ratio (HR) in Q5 versus Q1 was 1.30 (95 % confidence interval [CI],1.03-1.64) and 1.79 (95 % CI, 1.38-2.34), respectively. Per 1 unit increase in baseline and mean HbA1c was associated with 10 % (HR, 1.10; 95 % CI, 1.02-1.18) an 12 % (HR, 1.12; 95 % CI, 1.05-1.19) higher risk of stroke. Bayesian network analysis showed that the pathway from HbA1c to stroke was through hypertension, dyslipidemia, obesity, and inflammation.

CONCLUSIONS

Elevated levels of both baseline and long-term HbA1c were associated with increased risk of stroke, and hypertension and obesity played an important role in the pathway.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association for Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (HbA1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of HbA1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association of Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (Hb A1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of Hb A1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Can the level of HbA1C predict diabetic retinopathy among type II diabetic patients?

Background

Hemoglobin A1C (HbA₁C) test is the best care evaluation measurement due to a strong correlation between the test results and diabetic complications. So, this cross-sectional study aimed to assess whether the level of HbA₁C can predict Diabetic Retinopathy (DR) among Type 2 diabetes mellitus (T2DM) in the Iranian population.

Method

One hundred sixty-eight diabetic patients were selected via the convenience sampling method. Data were collected by research made questionnaire scale and laboratory test had been done. To estimate the cut off point for some variables statistical tests, formal measures of classification performance, model evaluation criteria and a decision Tree were used.

Results

The prevalence of DR was 29.8%. The Receiver Operating Characteristic (ROC) curve and decision tree showed the optimal cut-off point for the HbA1C variable that separates the patient with and without DR is HbA₁C = 8.15.

Conclusion

Current study showed an appropriate cutoff point for detecting the development of DR among diabetic patients. So, this cutoff point can be used as guide evidence in several clinical judgments on the Iranian population.

The Effect of Low Doses of Radon on Ghrelin and Glucose Levels in Rats with Multiple Low-Dose Streptozotoccin-induced Type 2 Diabetes Mellitus

AIM: The aim of our research was to identify the ghrelin concentration in experimental animals with type 2 diabetes mellitus (T2DM) and to study the effect of radon hormesis balneotherapy using natural thermal waters of Tskaltubo spring, practically, its effect on ghrelin and glucose metabolism. MATERIALS AND METHODS: To study the effect of radon in balneotherapy, group of experimental animals (multiple low doses streptozotocin-induced T2DM Wistar rats were used) went through the procedure of inhalation of radon by the Tskaltubo mineral water pool, once daily, during 10 days. In animals of the control groups, inhalation with radon was not used. The experimental group and the control group were brought from Tskaltubo to Tbilisi to the Ivane Beritashvili experimental biomedicine center, where the blood of the rats was analyzed. RESULTS: After radon inhalation therapy with Tskaltubo mineral water, a normalization of the ghrelin levels was observed in the experimental group and despite the different body weight, the levels were approximately the same and close to those of the control group. In the experimental group, ghrelin level normalization was accompanied by glycemia normalization. CONCLUSION: This research showed that Tskaltubo mineral water radon inhalation caused hormesis, which consequently decreased ghrelin levels in rodents with T2DM and obesity and the result was stable during 3 months. Ghrelin level stabilization positively influenced on glucose levels. The result of our experiment gives us a stimulus to continue future research to find more specific neurochemical mechanisms participating in radon hormesis processes and positively influencing on glucose levels and T2DM outcome.

Revised Glycemic Index for Diagnosing and Monitoring of Diabetes Mellitus in South Indian Population

Aim: To find the optimal threshold of fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) for diagnosis of diabetes mellitus (DM) and to evaluate the association with diabetic retinopathy (DR) in the South Indian population.

Settings and Design: A retrospective population-based study.

Methods and Materials: A total of 909 newly detected type 2 DM patients were selected from our two previously conducted studies, which include an urban and a rural population of South India. All underwent estimation of fasting, postprandial plasma glucose (PPG), and other biochemical tests. A comprehensive and detailed ophthalmic examination was carried out. The fundi of patients were photographed using 45°, four-field stereoscopic photography. Based on receiver operating characteristic (ROC) curves, sensitivity and specificity were derived.

Results: The optimal cut-off values determined by maximizing the sensitivity and specificity of FPG and HbA1c using the Youden index were ≥ 6.17 mmol/L and ≥ 6.3%, respectively. By distributing the cut-off points into deciles and comparing them to the WHO criteria, we found that our HbA1c level of 6.60% was more than the WHO threshold (6.5%), with higher sensitivity (81.6%) and lower specificity (48.3%). The FPG level of 6.80 mmol/L was lower to the WHO criteria (7 mmol/L) with increased sensitivity (77.0%) and lower specificity (45.7%). Prevalence of DR by HbA1c levels between 6.5% and 6.9% was 15.3%. The prevalence of DR was more in the FPG category between 6.4 and 6.9 mmol/L and ≥ 7.5 mmol/L.

Conclusion: Our population-based data indicate that for the South Indian population HbA1c value of ≥63 % and FPG value of ≥6.17 mmol/L may be optimal for diagnosing DM with a high level of accuracy and will be useful for the identification of mild and moderate DR.

Development and validation of a nomogram for assessing risk of isolated high 2-hour plasma glucose

A tool was constructed to assess need of an oral glucose tolerance test (OGTT) in patients whose fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are normal. Data was collected from the longitudinal REACTION study conducted from June to November 2011 (14,686 subjects, aged ≥ 40 y). In people without a prior history of diabetes, isolated high 2-hour plasma glucose was defined as 2-hour plasma glucose ≥ 11.1 mmol/L, FPG < 7.0 mmol/L, and HbA1c < 6.5%. A predictive nomogram for high 2-hour plasma glucose was developed via stepwise logistic regression. Discrimination and calibration of the nomogram were evaluated by the area under the receiver operating characteristic curve (AUC) and Hosmer-Lemeshow test; performance was externally validated in Northeast China. Parameters in the model included gender, age, drinking status, marriage status, history of hypertension and hyperlipidemia, waist-to-hip ratio, FPG, and HbA1c. All variables were noninvasive, except FPG and HbA1c. The AUC of the nomogram for isolated high 2-hour plasma glucose was 0.759 (0.727-0.791) in the development dataset. The AUCs of the internal and externally validation datasets were 0.781 (0.712-0.833) and 0.803 (0.778-0.829), respectively. Application of the nomogram during the validation study showed good calibration, and the decision curve analysis indicated that the nomogram was clinically useful. This practical nomogram model may be a reliable screening tool to detect isolated high 2-hour plasma glucose for individualized assessment in patients with normal FPG and HbA1c. It should simplify clinical practice, and help clinicians in decision-making.

The Role of Hemoglobin A1C in Diabetes Screening and Diabetic Retinopathy

Hemoglobin A1C (A1C) is used in various settings. Its performance has not been evaluated systemically. We compared A1C in diagnosis of diabetes with fasting plasma glucose (FPG) and 2-h postchallenged plasma glucose (2hPG) parameters in a cross-sectional cohort in the United Stated. Adult subjects (≥20 years) were identified from the National Health and Nutrition Examination Survey 2005-2016 without a history of diabetes who had BMI, A1C, FPG, and 2hPG (n = 10,416). For comparisons, we calculated the sample weighted prevalence, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with subgroup analyses. For the retinopathy study, diabetic subjects with established diabetes who responded to the question of diabetic retinopathy were evaluated (n = 3907). Compared to the FPG/2hPG criteria, A1C ≥ 48 mmol/mol (6.5%) had a low sensitivity at 25.90%, with specificity 99.70%, PPV 84.70%, and NPV 95.70%. Subgroup analyses revealed a lower sensitivity in males (24.52%); the lowest in non-Hispanic White (21.35%), in the third decade (14.32%), and in the BMI < 22.50 kg/m2 group (7.21%). The prevalence of self-reported diabetic retinopathy increased drastically with an inflection point at A1C 48 mmol/mol (6.5%) from 11.52% to 18.32% (p < 0.0001). A1C ≥ 48 mmol/mol (6.5%) should be cautiously used to diagnose diabetes in certain subgroups due to very low sensitivity in certain groups. With the confirmation of the association of increasing self-reported diabetic retinopathy with A1C ≥ 48 mmol/mol (6.5%), the current A1C cutoff is an acceptable value with the understanding of especially low sensitivity in certain subgroups.

Are Corporations Re-Defining Illness and Health? The Diabetes Epidemic, Goal Numbers, and Blockbuster Drugs

While pharmaceutical industry involvement in producing, interpreting, and regulating medical knowledge and practice is widely accepted and believed to promote medical innovation, industry-favouring biases may result in prioritizing corporate profit above public health. Using diabetes as our example, we review successive changes over forty years in screening, diagnosis, and treatment guidelines for type 2 diabetes and prediabetes, which have dramatically expanded the population prescribed diabetes drugs, generating a billion-dollar market. We argue that these guideline recommendations have emerged under pervasive industry influence and persisted, despite weak evidence for their health benefits and indications of serious adverse effects associated with many of the drugs they recommend. We consider pharmaceutical industry conflicts of interest in some of the research and publications supporting these revisions, and in related standard-setting committees and oversight panels. We raise concern over the long-term impact of these multifaceted involvements. Rather than accept industry conflicts of interest as normal, needing only to be monitored and managed, we suggest challenging that normalcy, and ask: what are the real costs of tolerating such industry participation? We urge the development of a broader focus to fully understand and curtail the systemic nature of industry's influence over medical knowledge and practice.

The retinopathy-derived HbA1c threshold of 6.5% for type 2 diabetes also captures the risk of diabetic nephropathy in NHANES

AIM

To determine if an HbA1c diagnostic threshold of less than 6.5% (<48 mmol/mol) could be identified based on a urinary albumin-creatinine ratio (UACR) of 30 mg/g or higher in subjects not known to have diabetes.

METHODS

A UACR was measured for 20 158 participants in the 2011-2018 nationally representative cross-sectional National Health and Nutrition Examination Surveys (NHANES; cycles 7-10 inclusive).

RESULTS

There was a significant trend for an increasing risk with a UACR of 30 mg/g or higher across increasing HbA1c categories (P < .0001). This trend was mainly attributable to the high prevalence of raised UACR in the 7.0% or higher HbA1c subgroup of subjects not previously diagnosed with diabetes. None of the odds ratios in the lower HbA1c subgroups versus the HbA1c subgroup of less than 5.0% reached significance. There were racial/ethnic differences in UACR risk (P < .0001), with White and Black subjects exhibiting little increased risk (vs. HbA1c <5.0%) until they reached an HbA1c of 7.0%, while Asian and Hispanic subjects showed some increased, but non-significant, risks at lower HbA1c levels. Maximizing the area under receiver operating characteristic curves from logistic regressions predicted an ideal HbA1c threshold of 5.8%, but there was little variation in area from 5.5% to 7.0%.

CONCLUSION

A clinically useful diagnostic threshold below 6.5% for HbA1c for elevated UACR risk was not identified, with an increased risk only obvious at an HbA1c of 7.0% or higher. Thus, the retinopathy-derived HbA1c threshold of 6.5% also captures the risk of diabetic nephropathy in NHANES.

Independent effects of 2hPG, FPG and HbA1c on cardiovascular risk: Analysis of a nationally representative sample from China

AIMS

To evaluate the independence of the effect of 2-hour post-load plasma glucose (2hPG), fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) on cardiovascular disease (CVD) after adjusting for each other and non-glycemic factors.

METHODS

We analyzed data from a nationally representative sample of 174,329 Chinese adults from a survey conducted in 2013-2014. The associations of glycemic measures with the risk of CVD were examined and compared by using logistic regression analyses.

RESULTS

After adjusting for non-glycemic factors, the odds ratio for one standard-deviation increase of 2hPG, FPG and HbA1c was 1.08 (95% confidence interval [CI]: 1.05-1.11), 1.02 (95% CI: 0.99-1.06) and 1.05 (95% CI: 1.02-1.07), respectively. The odds ratio for 2hPG (1.10, 95% CI: 1.05-1.16) remained statistically significant after FPG and HbA1c were added to the models, whereas the odds ratios for FPG and HbA1c became statistically insignificant after 2hPG was adjusted for. The results remained consistent across various scenarios.

CONCLUSIONS

2hPG showed an effect on cardiovascular risk which was independent from FPG and HbA1c, whereas whether the effects of FPG and HbA1c were independent from 2hPG was open to question. This finding calls for more research on how to better use FPG and HbA1c in diagnosing diabetes.

Diagnosing type 2 diabetes using Hemoglobin A1c: a systematic review and meta-analysis of the diagnostic cutpoint based on microvascular complications

AIMS

Diabetic microvascular complications of retinopathy, nephropathy and neuropathy may occur at hemoglobin A1c levels (HbA1c) below the 6.5% (48 mmol/mol) diagnostic threshold. Our objective was to assess the validity of the HbA1c diagnostic cutpoint of 6.5% based upon published evidence of the prevalence of retinopathy, nephropathy and neuropathy as markers of diabetes.

METHODS

Data Sources PubMed, Embase, Cochrane, Scopus and CINAHL from 1990-March 2019, grey literature sources. Study Selection All studies reported after 1990 (to ensure standardized HbA1c values) where HbA1c levels were presented in relation to prevalence of retinopathy, nephropathy or neuropathy in subjects not known to have diabetes. Data Extraction Studies were screened independently, data abstracted, and risk of bias appraised. Data Synthesis Data were synthesized using HbA1c categories of < 6.0% (< 42 mmol/mol), 6.0-6.4% (42-47 mmol/mol) and ≥ 6.5% (≥ 48 mmol/mol). Random-effects meta-analyses were conducted for retinopathy, nephropathy and neuropathy prevalence stratified by HbA1c categories. Random-effects multivariable meta-regression was conducted to identify predictors of retinopathy prevalence and sources of between-study heterogeneity.

RESULTS

Pooled mean prevalence was: 4.0%(95% CI: 3.2-5.0%) for retinopathy, 10.5% (95% CI: 4.0-19.5%) for nephropathy, 2.5% (95% CI: 1.1-4.3%) for neuropathy. Mean prevalence when stratified for HbA1c < 6.0%, 6.0-6.4% and ≥ 6.5% was: retinopathy: 3.4% (95% CI: 1.8-5.4%), 2.3% (95% CI: 1.6-3.2%) and 7.8%(95% CI: 5.7-10.3%); nephropathy: 7.1% (95% CI: 1.7-15.9%), 9.6% (95% CI: 0.8-26.4%) and 17.1% (95% CI: 1.0-46.9%); neuropathy: 2.1% (95% CI: 0.0-6.8%), 3.4% (95% CI: 0.0-11.6%) and 2.8% (95% CI: 0.0-12.8%). Multivariable meta-regression showed HbA1c ≥ 6.5% (OR: 4.05; 95% CI: 1.92-8.57%), age > 55 (OR: 3.23; 95% CI 1.81-5.77), and African-American race (OR: 10.73; 95% CI: 4.34-26.55), to be associated with higher retinopathy prevalence. Marked heterogeneity in prevalence estimates was found across all meta-analyses (Cochran's Q-statistic p < 0.0001).

CONCLUSIONS

The prevalence of nephropathy and moderate retinopathy was increased in subjects with HbA1c values ≥ 6.5% confirming the high specificity of this value for diagnosing T2DM; however, at HbA1c < 6.5% retinopathy increased at age > 55 years and, most strikingly, in African-Americans, suggesting there may be excess microvascular complication prevalence (particularly nephropathy) in individuals below the diabetes diagnostic threshold.

A comparison in the ability to detect diabetic retinopathy between fasting plasma glucose and HbA1c levels in a longitudinal study

Aims

The relationship between HbA1c and diabetic retinopathy is expected to differ between different races. In this study, we verified which of HbA1c and fasting plasma glucose (FPG) is more effective for detecting the diabetic retinopathy longitudinally in a Japanese population.

Materials and Methods

The study subjects underwent health examinations twice (including eye test and questionnaire of lifestyle and health) in 2008-2009 (baseline) and in 2012-2013 (4-year follow-up). Both non-DM and DM patients at baseline were included as the participants. Of these participants, who had not been diagnosed with retinopathy at the baseline survey (n = 2427; 2150 men and 277 women) had eye fundus photographs taken four years later (follow-up survey). The odds ratios of incidence of retinopathy according to the eight groups of FPG and HbA1c were estimated using multiple logistic regression analysis adjusted for sex and age. Receiver operator characteristic analysis was used to evaluate each value associated with the presence or absence of retinopathy.

Results

The odds ratios (95% confidence intervals) of incidence of retinopathy by HbA1c level categories, in ascending order, were 1.0 (ref.), 5.66 (1.14-28.26), 1.69 (0.24-12.04), 3.03 (0.50-18.28), 1.04 (0.09-11.59), 4.73 (0.78-28.69), 4.12 (0.74-22.85) and 24.47 (5.61-106.75). For both FPG and HbA1c levels, the odds ratio for the development of retinopathy increased linearly with the increases in the levels FPG and HbA1c, and no clear threshold was observed. The AUC values (SE) for FPG and HbA1c were almost the same, at 0.750 (0.046) and 0.732 (0.048).

Conclusions

It was clarified that the higher the level of FPG and HbA1c was, the higher the incidence of retinopathy after 4 years was. There was no clear threshold. The detection ability of the incidence of retinopathy was almost the same between FPG and HbA1c, suggesting it is possible to detect the risk of retinopathy by HbA1c only.

Predictive Performance of Glycated Hemoglobin for Incident Diabetes Compared with Glucose Tolerance Test According to Central Obesity

BACKGROUND

To examine whether glycated hemoglobin (HbA1c) test would be a suitable screening tool for detecting high-risk subjects for diabetes compared to oral glucose tolerance test (OGTT) according to accompanied central obesity.

METHODS

In this prospective population-based cohort study, both OGTT and HbA1c tests were performed and continued every 2 years up to 12 years among individuals with non-diabetic state at baseline (aged 40 to 69 years, n=7,512). Incident diabetes was established by a doctor, HbA1c ≥6.5%, and/or fasting plasma glucose (FPG) ≥126 mg/dL, and/or 2-hour postprandial glucose (2hPG) level based on OGTT ≥200 mg/dL. Discriminative capacities of high HbA1c (≥5.7%) versus high 2hPG (≥140 mg/dL) for predicting incident diabetes were compared using Cox-proportional hazard regression and C-index.

RESULTS

During the median 11.5 years of follow-up period, 1,341 (17.6%) developed diabetes corresponding to an incidence of 22.1 per 1,000 person-years. Isolated high 2hPG was associated with higher risk for incident diabetes (hazard ratio [HR], 4.29; 95% confidence interval [CI], 3.56 to 5.17) than isolated high HbA1c (HR, 2.79; 95% CI, 2.40 to 3.26; P<0.05). In addition, high 2hPG provided better discriminatory capacity than high HbA1c (C-index 0.79 vs. 0.75, P<0.05). Meanwhile, in subjects with central obesity, the HR (3.95 [95% CI, 3.01 to 5.18] vs. 2.82 [95% CI, 2.30 to 3.46]) and discriminatory capacity of incident diabetes (C-index 0.75 vs. 0.75) between two subgroups became comparable.

CONCLUSION

Even though the overall inferior predictive capacity of HbA1c test than OGTT, HbA1c test might plays a complementary role in identifying high risk for diabetes especially in subjects with central obesity with increased sensitivity.

The Oral Glucose Tolerance Test: 100 Years Later

For over 100 years, the oral glucose tolerance test (OGTT) has been the cornerstone for detecting prediabetes and type 2 diabetes (T2DM). In recent decades, controversies have arisen identifying internationally acceptable cut points using fasting plasma glucose (FPG), 2-h post-load glucose (2-h PG), and/or HbA1c for defining intermediate hyperglycemia (prediabetes). Despite this, there has been a steadfast global consensus of the 2-h PG for defining dysglycemic states during the OGTT. This article reviews the history of the OGTT and recent advances in its application, including the glucose challenge test and mathematical modeling for determining the shape of the glucose curve. Pitfalls of the FPG, 2-h PG during the OGTT, and HbA1c are considered as well. Finally, the associations between the 30-minute and 1-hour plasma glucose (1-h PG) levels derived from the OGTT and incidence of diabetes and its complications will be reviewed. The considerable evidence base supports modifying current screening and diagnostic recommendations with the use of the 1-h PG. Measurement of the 1-h PG level could increase the likelihood of identifying high-risk individuals when the pancreatic ß-cell function is substantially more intact with the added practical advantage of potentially replacing the conventional 2-h OGTT making it more acceptable in the clinical setting.

Optimal fasting plasma glucose and haemoglobin A1c levels for screening of prediabetes and diabetes according to 2-hour plasma glucose in a high-risk population: The Korean Diabetes Prevention Study

BACKGROUND

The primary aim of this study was to assess the utility of fasting plasma glucose (FPG) and HbA1c to identify diabetes by the 2-hour plasma glucose (PG) criterion in the Korean population at high risk for diabetes.

METHODS

A total of 1646 participants with a body mass index of ≥23 kg/m2 without having a history of diabetes were recruited in this study. The cut-off values of FPG and HbA1c for detecting diabetes were identified using the Youden index using receiver operating characteristic (ROC) analysis. The gold standard for diabetes prediction was defined by the 2-hour PG level of ≥200 mg/dL.

RESULTS

The participants comprised 54.0% women, and the mean age of all participants was 55.0 ± 8.1 years. At baseline, FPG was 104.1 ± 14.2 mg/dL, the 2-hour PG value was 162.9 ± 55.3 mg/dL, and HbA1c was 5.9% ± 0.5%. Four hundred and forty-six subjects (27.1%) were diagnosed with diabetes and 976 subjects (59.3%) were determined to be at prediabetes. The area under the ROC curve (AUC) of FPG and HbA1c for diabetes were 0.776 and 0.802, while the AUC of FPG and HbA1c for prediabetes were 0.515 and 0.477. The optimal cut-off value for diagnosing diabetes of FPG and HbA1c were 104.5 mg/dL (sensitivity 75.8%, specificity 67.5%) and 5.9% (sensitivity 80.6%, specificity 63.8%), respectively.

CONCLUSIONS

FPG of 104.5 mg/dL and HbA1c value of 5.9% (41 mmol/mol) can be used as an optimal screening value for diabetes by 2-hour PG criterion in the Korean population at high risk for diabetes.

Review of methods for detecting glycemic disorders

Prediabetes (intermediate hyperglycemia) consists of two abnormalities, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) detected by a standardized 75-gram oral glucose tolerance test (OGTT). Individuals with isolated IGT or combined IFG and IGT have increased risk for developing type 2 diabetes (T2D) and cardiovascular disease (CVD). Diagnosing prediabetes early and accurately is critical in order to refer high-risk individuals for intensive lifestyle modification. However, there is currently no international consensus for diagnosing prediabetes with HbA1c or glucose measurements based upon American Diabetes Association (ADA) and the World Health Organization (WHO) criteria that identify different populations at risk for progressing to diabetes. Various caveats affecting the accuracy of interpreting the HbA1c including genetics complicate this further. This review describes established methods for detecting glucose disorders based upon glucose and HbA1c parameters as well as novel approaches including the 1-hour plasma glucose (1-h PG), glucose challenge test (GCT), shape of the glucose curve, genetics, continuous glucose monitoring (CGM), measures of insulin secretion and sensitivity, metabolomics, and ancillary tools such as fructosamine, glycated albumin (GA), 1,5- anhydroglucitol (1,5-AG). Of the approaches considered, the 1-h PG has considerable potential as a biomarker for detecting glucose disorders if confirmed by additional data including health economic analysis. Whether the 1-h OGTT is superior to genetics and omics in providing greater precision for individualized treatment requires further investigation. These methods will need to demonstrate substantially superiority to simpler tools for detecting glucose disorders to justify their cost and complexity.

Reproducibility of a prediabetes classification in a contemporary population

Aims

To assess whether meeting both fasting plasma glucose (FPG) and HbA1c criteria for prediabetes in people at high risk indicates with near certainty the presence of dysglycemia on repeat testing.

Methods

Observational study using data from Vitamin D and Type 2 Diabetes (D2d) study. HbA1c, FPG were measured at screening visit 1; FPG, HbA1c and 2 h plasma glucose (2hPG) measured at screening visit 2 (a median of 21 days later); participants classified as having normal glucose regulation (all 3 tests in normal range), prediabetes or diabetes (at least 1 of 3 tests in diabetes range). A predictive model was developed to estimate the probability of confirming dysglycemia and for detecting diabetes at screening visit 2 based on values of FPG and HbA1c at screening visit 1.

Results

Of 1271 participants who met both FPG and HbA1c criteria for prediabetes at screening visit 1, 98.6% exhibited dysglycemia (defined as prediabetes or diabetes) on repeat testing (84.5% were classified as having prediabetes, 14.1% were reclassified as having diabetes). Of those with diabetes, 62.6% were identified by 2hPG alone.

Conclusions

Combined measurement of FPG and HbA1c is a reliable and reproducible measure to identify presence of dysglycemia among people at high risk. A prediction model is provided to help clinicians decide whether an oral glucose tolerance test will provide value in detecting diabetes based on the 2hPG criterion.

Intermittent low dose carbon monoxide inhalation does not influence glucose regulation in overweight adults: a randomized controlled crossover trial

NEW FINDINGS

What is the central question of this study? Low dose carbon monoxide (CO) inhalation plays a role in regulating proteins involved in glucose metabolism; does low dose CO improve glucose and insulin responses to an oral glucose tolerance test in overweight adults? What is the main finding and its importance? Five days of intermittent CO inhalation does not alter the glucose or insulin responses to ingestion of a glucose bolus in overweight adults. Low dose CO is utilized in various physiological assessment procedures; these findings allow researchers and clinicians to utilize these procedures without concern of altering glucose metabolism.

ABSTRACT

Low dose carbon monoxide (CO) inhalation upregulates several proteins important for glucose metabolism. Such changes could be clinically significant and may be relevant to those who use CO as a research tool. We hypothesized that low dose CO inhalation would improve glucose and insulin responses to an oral glucose bolus in overweight humans. Eleven young adults (5 men, 6 women; body mass index: 25-35 kg m^-2 ) were included in this randomized, placebo-controlled, single-blinded crossover study. Following screening, participants completed two 7-day protocols with a 4-week washout. Twenty-four hours prior to and following five consecutive days of either once daily CO (men: 1.2 ml (kg body mass)^-1 ; women: 1.0 ml (kg body mass)^-1 ) or placebo (room air) inhalation, participants underwent oral glucose tolerance tests (OGTT). For key outcome variables, there were no significant main effects or interactions across condition or time point (mean ± SD), including fasting glucose (mg dl^-1 : pre-placebo: 85.2 ± 10.1; post-placebo: 82.9 ± 10.6; pre-CO: 83.6 ± 7.7; post-CO: 84.0 ± 9.0), 2 h post glucose (mg dl^-1 : pre-placebo: 100.9 ± 20.0; post-placebo: 98.7 ± 13.1; pre-CO: 94.2 ± 23.2; post-CO: 94.4 ± 14.9), or the Matsuda index (pre-placebo: 16.1 ± 11.5; post-placebo: 20.3 ± 24.7; pre-CO: 15.6 ± 15.3; post-CO: 17.5 ± 16.8). In conclusion, 5 days of low dose CO administration did not influence glucose and insulin responses to an OGTT in overweight adults. Low dose CO inhalation is utilized in a variety of physiological assessment procedures; these findings allow researchers to utilize these procedures without concern of altering glucose metabolism.

A Comparison of the Association of Fasting Plasma Glucose and HbA1c Levels with Diabetic Retinopathy in Japanese Men

INTRODUCTION

The relationship between HbA1c and diabetic retinopathy is expected to differ between different races. This study was designed to verify whether HbA1c or fasting plasma glucose (FPG) is more effective in detecting diabetic retinopathy in a Japanese population.

MATERIALS AND METHODS

The study subjects underwent health examinations between 2008 and 2009 with fasting. Of these participants, we analyzed the data for 2,921 Japanese men who had undergone an ophthalmologic examination. Retinopathy was classified into 7 categories according to a simplified diabetic retinopathy scale. The odds ratios of retinopathy according to the eight groups of FPG and HbA1c were estimated using multiple logistic regression analysis adjusted for age. Receiver operator characteristic analysis was used to evaluate each value associated with the presence or absence of retinopathy. Results and Discussion. The odds ratios (95% CI) of retinopathy for HbA1c level categories, in ascending order, were 1.0 (ref.), 0.88 (0.28-2.75), 1.27 (0.44-3.69), 1.52 (0.48-4.79), 1.89 (0.52-6.85), 2.70 (0.66-11.10), 4.10 (0.80-21.00), and 6.34 (2.37-16.97) where the odds ratios significantly increased with HbA1c ≥ 6.8%. The area under the curve (SE) for FPG and HbA1c was almost the same, at 0.668 (0.043) and 0.680 (0.043), respectively.

CONCLUSIONS

It was clarified that the higher the level of HbA1c, the higher the prevalence of retinopathy, and there was no clear threshold. The detection ability of retinopathy was almost the same, suggesting that it is possible to detect the risk of retinopathy by HbA1c only.

Pilot test of an educational intervention to improve self-management of diabetes in persons living with HIV

People living with a diagnosis of HIV (PLWH) and type 2 diabetes (T2DM) can experience a synergistic negative impact on their vascular and immune systems if their conditions are poorly controlled. The purpose of this study was to adapt a community-based diabetes self-management intervention for people living with HIV and test the feasibility of administering the intervention with PLWH+T2DM who are low-income, predominantly minority, vulnerable population. The intervention was 12 weeks long with 6 h of educational instruction followed by 6 weekly support telephone calls to reinforce training and problem solve. The study used a one-group pretest-posttest design. Participants were a convenience sample of 25 adults diagnosed with HIV + T2DM. Diabetes knowledge, HIV knowledge, and self-management skills were measured. Analyses comprised descriptive statistics and correlations. Participants completed an average of 2.7 of 6 h of instruction and an average of 3 of 6 possible telephone calls. There was a 34% increase in diabetes self-management skills from pretest to posttest, but there were no changes in knowledge about HIV or diabetes. Based on this pilot study, next steps will include a multi-modal educational intervention, with in-person, at-home, and teleconference components. Blood sample collection procedure will be coordinated with study visits to decrease participants' burden, and the updated diabetes knowledge instrument with a higher reported internal consistency will be used.

Bimodal distribution of fasting, one and two hour post load plasma glucose in Asian Indian pregnant women without pre-gestational diabetes: Gestational age related changes

•After exclusion of pre-gestational diabetes, Asian Indian pregnant women have bimodal distribution of plasma glucose.•Bimodality is observed for fasting, 1 and 2 h post glucose load plasma glucose distribution.•Cut off values for gestational diabetes diagnosis could not identified for any glucose parameter.•In women with high gestational diabetes risk factors, the bimodality is evident before 24 weeks of gestation.•By third trimester, the bimodality is significant for all glucose parameters.

Dietary Supplementation of Vine Tea Ameliorates Glucose and Lipid Metabolic Disorder via Akt Signaling Pathway in Diabetic Rats

A traditional Chinese tea with many pharmacological effects, vine tea (VT) is considered a potential dietary supplement to improve type 2 diabetes (T2D). To investigate the effect and mechanism of VT on glucose and lipid metabolic disorders in T2D rats, Wistar rats fed a normal diet served as the normal control, while rats fed a high-fat diet combined with low-dose streptozotocin (STZ)-induced T2D were divided into three groups: The model group (MOD); the positive control group (MET, metformin at 200 mg/kg/d); and the VT-treated group (VT500, allowed to freely drink 500 mg/L VT). After four weeks of intervention, biochemical metrics indicated that VT significantly ameliorated hyperglycemia, hyperlipidemia and hyperinsulinemia in T2D rats. Metabolomics research indicated that VT regulated the levels of metabolites closely related to glucose and lipid metabolism and promoted glycogen synthesis. Furthermore, VT had a significant influence on the expression of key genes involved in the Akt signaling pathway, inhibited gluconeogenesis through the Akt/Foxo1/Pck2 signaling pathway, and reduced fatty acid synthesis via the SREBP1c/Fasn signaling pathways. In conclusion, VT has great potential as a dietary supplement to ameliorate glucose and lipid metabolic disorders via the Akt signaling pathway in T2D rats.

Reconsidering the HbA1c Cutoff for Diabetes Diagnosis Based on a Large Chinese Cohort

INTRODUCTION

The HbA1c has been considered as the 'gold standard' in diabetes diagnosis and management, however, age, gender and body mass index (BMI) might have certain effects on HbA1c. We are aiming to further investigate the correlation between age and HbA1c, and whether it was affected by gender and BMI.

METHODS

A cross-sectional survey including 135,893 nondiabetic individuals who took the physical examination between 2013 and 2017 was conducted. The subjects were grouped by gender, age and BMI, and the interactive and independent effects of the 3 factors on the HbA1c were detected. The median and 95% confidence interval (CI) of HbA1c levels were calculated.

RESULTS

The HbA1c levels gradually increased along with age, both in female and male, and there is a positive association between BMI and the HbA1c. The difference on HbA1c in gender was associated with both age and BMI, the age-related increase in HbAlc was accentuated in the subgroup with higher BMI, and there was a marked accentuation of the positive association between BMI and HbA1c as age increased. In almost all the young and middle-aged (aged 20-59) subgroups, the 97.5^th percentiles of HbA1c levels were lower than 6.5%, suggesting that the single HbA1c cutoff value is probably not applicable to the young and middle-aged population.

CONCLUSIONS

We recommend that the effects of age, gender and BMI should be taken into consideration when using HbA1c for the diagnosis and management of diabetes, especially in the young and middle-aged population.

Different Analysis of β-Cell Dysfunction as Fasting Glucose Progresses in Obese and Nonobese Newly Diagnosed Type 2 Diabetic Patients

AIMS/INTRODUCTION

This study is aimed at (1) investigating the change of β-cell dysfunction as baseline fasting glucose progresses in newly diagnosed patients with T2DM and (2) finding whether body mass index (BMI) has different degrees of impact on insulin secretion as baseline fasting glucose progresses.

MATERIALS AND METHODS

661 patients with newly diagnosed T2DM were enrolled in the present study. A 75 g oral glucose tolerance test was used to calculate HOMA-β, HOMA-IR, early-phase insulin secretion index (EISI, calculated as ΔI₃₀/ΔG₃₀), and area under the insulin releasing curve (AUC_I0-180). Patients were divided into low, medium, and high FBG groups. Each group was further divided into lean, overweight, and obese subgroups according to BMI.

RESULTS

A decrease of EISI and HOMA-β and an increase of HOMA-IR were shown among different FBG groups significantly. In the medium FBG group, AUC_I0-180, EISI, HOMA-β, and HOMA-IR in obese patients were higher than those in lean and overweight patients. In the low and high FBG groups, AUC_I0-180, HOMA-β, and HOMA-IR in obese patients were higher than those in other subgroups. BMI was positively associated with high EISI in the medium FBG group but failed to yield a significant association with EISI in the low and high FBG groups.

CONCLUSIONS

During the progression of baseline FBG, β-cell dysfunction and insulin resistance worsened. As FBG increased, increased BMI had a positive influence on β-cell dysfunction in all FBG groups. The independent factors that correlated to EISI differed with the increasing of baseline FBG.

Petition to replace current OGTT criteria for diagnosing prediabetes with the 1-hour post-load plasma glucose ≥ 155 mg/dl (8.6 mmol/L)

Many individuals with prediabetes, as presently defined, will progress to diabetes (T2D) despite the considerable benefit of lifestyle modification. Therefore, it is paramount to screen individuals at increased risk with a more sensitive method capable of identifying prediabetes at an even earlier time point in the lengthy trajectory to T2D. This petition reviews findings demonstrating that the 1-hour (1-h) postload plasma glucose (PG) ≥ 155 mg/dl (8.6 mmol/L) in those with normal glucose tolerance (NGT) during an oral glucose tolerance test (OGTT) is highly predictive for detecting progression to T2D, micro- and macrovascular complications and mortality in individuals at increased risk. Furthermore, the STOP DIABETES Study documented effective interventions that reduce the future risk of T2D in those with NGT and a 1-h PG ≥ 155 mg/dl (8·6 mmol/L). The 1-h OGTT represents a valuable opportunity to extend the proven benefit of diabetes prevention to the sizeable and growing population of individuals at increased risk of progression to T2D. The substantial evidence provided in this petition strongly supports redefining current diagnostic criteria for prediabetes with the elevated 1-h PG level. The authors therefore advocate a 1-h OGTT to detect prediabetes and hence, thwart the global diabetes epidemic.

Overdiagnosis in primary care: framing the problem and finding solutions

Overdiagnosis, is defined as the diagnosis of a condition that, if unrecognized, would not cause symptoms or harm a patient during his or her lifetime, and it is increasingly acknowledged as a consequence of screening for cancer and other conditions. Because preventive care is a crucial component of primary care, which is delivered to the broad population, overdiagnosis in primary care is an important problem from a public health perspective and has far reaching implications. The scope of overdiagnosis as a result of services delivered in primary care is unclear, though overdiagnosis of indolent breast, prostate, thyroid, and lung cancers is well described and overdiagnosis of chronic kidney disease, depression, and attention-deficit/hyperactivity disorder is also recognized. However, overdiagnosis is a known consequence of all screening and can be assumed to occur in many more clinical contexts. Overdiagnosis can harm patients by leading to overtreatment (with associated potential toxicities), diagnosis related anxiety or depression, and labeling, or through financial burden. Many entrenched factors facilitate overdiagnosis, including the growing use of advanced diagnostic technology, financial incentives, a medical culture that encourages greater use of tests and treatments, limitations in the evidence that obscure the understanding of diagnostic utility, use of non-beneficial screening tests, and the broadening of disease definitions. Efforts to reduce overdiagnosis are hindered by physicians' and patients' lack of awareness of the problem and by confusion about terminology, with overdiagnosis often conflated with related concepts. Clarity of terminology would facilitate physicians' understanding of the problem and the growth in evidence regarding its prevalence and downstream consequences in primary care. It is hoped that international coordination regarding diagnostic standards for disease definitions will also help minimize overdiagnosis in the future.

Bimodal glucose distribution in Asian Indian pregnant women: Relevance in gestational diabetes mellitus diagnosis

•

Pregnant Asian Indian women have bimodality in plasma glucose distribution.

•

Bimodality is evident even in very young pregnant women of age 18–23 years.

•

Glucose cut points may suggest thresholds for gestational diabetes diagnosis.

Aims

Presence of bimodality in plasma glucose distribution (BPG) and its relevance for gestational diabetes mellitus (GDM) diagnosis were studied in Asian Indian pregnant women.

Methods

Fasting (FPG) and two hour plasma glucose (2-h PG) values of oral glucose tolerance tests performed in 36,530 pregnant women for GDM screening (2006–16 period), were analyzed for BPG. A unimodal normal and a mixture of two normal distributions were fitted to log-transformed FPG and 2-h PG data. The mixture model was compared to unimodal model for BPG using likelihood ratio test (LRT) and the comparison was further verified by bootstrapping. The cut points of the two normal distribution curves in the mixture models of FPG and 2-h PG were noted.

Results

Fasting and 2-h PG distribution was bimodal in all pregnant women. The comparison of mixture and unimodal models using LRT revealed p value <0.001 in all age groups. The cut points for FPG and 2-h PG were 5.81 mmol/L (95% CI: 5.69–5.92) and 8.41 mmol/l (95% CI: 8.09–8.75) respectively.

Conclusion

BPG is noted for both FPG and 2-hPG in Asian Indian pregnant women. The cutpoints of normal distribution curves are close to threshold values for FPG and 2-h PG proposed in NICE (National Institute for health and Care Excellence) and IADPSG (International Association of Diabetes and Pregnancy Study Group) GDM diagnostic criteria respectively. Further research on BPG in pregnant women of racial groups with high GDM prevalence, is likely to be of value in GDM diagnosis.

Increased Oral Porphyromonas gingivalis Prevalence in Cardiovascular Patients with Uncontrolled Diabetes Mellitus

The aim of this study was to determine the correlation between periodontopathic bacteria and diabetes mellitus (DM) status in cardiovascular disease (CVD) subjects.DM is associated with the progression of periodontitis. Several epidemiological studies have suggested that periodontitis may be a risk factor for CVD. However, no study has compared the periodontal condition between well-controlled and poorly-controlled DM patients with CVD.The subjects were well-controlled (n = 73) or poorly-controlled (n = 39) DM patients with CVD. Blood examinations and dental clinical measurements, including number of teeth, probing pocket depth, bleeding on probing (BOP), and clinical attachment level (CAL) were performed. Periodontopathic bacterial existence was evaluated.Worsened CAL and BOP rate were detected in the uncontrolled DM group compared to the controlled group. We found increased salivary Porphyromonas gingivalis counts in the uncontrolled DM group compared to well-controlled DM subjects.Specific periodontopathic bacterial infection may affect DM condition in CVD patients.

One-Hour Plasma Glucose Compared With Two-Hour Plasma Glucose in Relation to Diabetic Retinopathy in American Indians

OBJECTIVE

We compared the ability of 1- and 2-h plasma glucose concentrations (1h-PG and 2h-PG, respectively), derived from a 75-g oral glucose tolerance test (OGTT), to predict retinopathy. 1h-PG and 2h-PG concentrations, measured in a longitudinal study of an American Indian community in the southwestern U.S., a population at high risk for type 2 diabetes, were analyzed to assess the usefulness of the 1h-PG to identify risk of diabetic retinopathy (DR).

RESEARCH DESIGN AND METHODS

Cross-sectional (n = 2,895) and longitudinal (n = 1,703) cohorts were assessed for the prevalence and incidence of DR, respectively, in relation to deciles of 1h-PG and 2h-PG concentrations. Areas under the receiver operating characteristic (ROC) curves for 1h-PG and 2h-PG were compared with regard to predicting DR, as assessed by direct ophthalmoscopy.

RESULTS

Prevalence and incidence of DR, based on direct ophthalmoscopy, changed in a similar manner across the distributions of 1h-PG and 2h-PG concentrations. ROC analysis showed that 1h-PG and 2h-PG were of similar value in identifying prevalent and incident DR using direct ophthalmoscopy. 1h-PG cut points of 230 and 173 mg/dL were comparable to 2h-PG cut points of 200 mg/dL (type 2 diabetes) and 140 mg/dL (impaired glucose tolerance), respectively.

CONCLUSIONS

1h-PG is a useful predictor of retinopathy risk, has a predictive value similar to that of 2h-PG, and may be considered as an alternative glucose time point during an OGTT.

Optimal cutoff values of fasting plasma glucose (FPG) variability for detecting retinopathy and the threshold of FPG levels for predicting the risk of retinopathy in type 2 diabetes: A longitudinal study over 27 years

AIMS

To determine the cutoff values of fasting plasma glucose (FPG) variability for detecting retinopathy and examine the threshold of FPG levels for predicting retinopathy incidence in type 2 diabetes.

METHODS

Subjects comprised 170 patients with type 2 diabetes who had no retinopathy at their first visit, and continuously visited thereafter for 27 years. Retinopathy was evaluated by ophthalmologists at least annually.

RESULTS

114 patients developed retinopathy. 46 of them had advanced retinopathy. The optimal cutoff values of intrapersonal mean and standard deviation (SD) of FPG over 27 years and intrapersonal mean HbA1c from the initial measurement to the last visit for detecting retinopathy were 7.4 mmol/L, 1.4 mmol/L, and 7.2% (56 mmol/mol), respectively. Similarly, for advanced retinopathy, 7.7 mmol/L, 1.9 mmol/L, and 7.5% (59 mmol/mol), respectively. Hazard ratios of deciles of intrapersonal mean FPG (mmol/L) during the initial 2 years for retinopathy incidence significantly increased from eighth-decile (6.9-7.4), and were sharply elevated from ninth-decile (7.4-8.7).

CONCLUSIONS

Our study provides new cutoff values for FPG variability. Cutoff values of FPG and HbA1c were slightly higher than recommended targets of the current guideline. The threshold of FPG levels (6.9 mmol/L) is proposed to predict retinopathy incidence during the subsequent 25 years.

Hemoglobin A1c and diagnosis of diabetes

The prevalence of diabetes is increasing markedly worldwide, especially in China. Hemoglobin A1c is an indicator of mean blood glucose concentrations and plays an important role in the assessment of glucose control and cardiovascular risk. In 2010, the American Diabetes Association included HbA1c ≥6.5% into the revised criteria for the diagnosis of diabetes. However, the debate as to whether HbA1c should be used to diagnose diabetes is far from being settled and there are still unanswered questions regarding the cut-off value of HbA1c for diabetes diagnosis in different populations and ethnicities. This review briefly introduces the history of HbA1c from discovery to diabetes diagnosis, key steps towards using HbA1c to diagnose diabetes, such as standardization of HbA1c measurements and controversies regarding HbA1c cut-off points, and the performance of HbA1c compared with glucose measurements in the diagnosis of diabetes.

Validity and reliability of a novel metabolic flexibility test in children with obesity

Existing methods for diagnosing diabetes and for identifying risk of diabetes development are completed under resting conditions and based on adult data. Studying additional methods to identify metabolic risk in children is warranted. Our objective was to examine the validity and reliability of a metabolic flexibility (MetFlex) test for screening glycemia and insulin resistance (IR) in children. We hypothesized higher MetFlex during exercise would be correlated with lower fasting glucose and homeostasis model assessment of insulin resistance (HOMA-IR) and higher whole body insulin sensitivity index (WBISI) and insulin secretion-sensitivity index-2 (ISSI-2). Thirty-four children with obesity (14 boys, 20 girls) attended two visits. At visit 1, an oral glucose tolerance test (OGTT) was followed by anthropometric and aerobic fitness (V̇o_2max) assessments. Insulin and glucose during the OGTT were used to calculate HOMA-IR, WBISI, and ISSI-2. At visit 2, a ¹³C-enriched carbohydrate drink was ingested before 60 min of exercise at 45% V̇o_2max. Breath measurements were collected to calculate area under the curve exogenous carbohydrate to measure MetFlex. Pearson's r correlation showed no significant association between MetFlex during exercise with fasting glucose ( r = -0.288, P = 0.110). MetFlex was associated with log-HOMA-IR ( r = -0.597, P = 0.024), log-WBISI ( r = 0.575, P = 0.051), and log-ISSI-2 ( r = 0.605, P = 0.037) in boys but not girls. When repeated ( n = 18), MetFlex was deemed a reliable test (intraclass correlation coefficient = 0.692). MetFlex during exercise was negatively associated with IR and β-cell function in boys. Further research is required to explore clinical utility of the MetFlex test and explain the lack of association in girls. NEW & NOTEWORTHY This study is the first to investigate the validity and reliability of a novel noninvasive metabolic flexibility (MetFlex) test for identifying insulin resistance in children with obesity. MetFlex was measured during exercise using [¹³C]glucose stable isotope methodology. Findings showed that MetFlex was negatively associated with insulin resistance in boys but not in girls with obesity. Future work is required to investigate these sex differences. MetFlex test results were deemed reliable when repeated on a separate day.

Discordance in the diagnosis of diabetes: Comparison between HbA1c and fasting plasma glucose

OBJECTIVE

HbA1c has been introduced as a complementary diagnostic test for diabetes, but its impact on disease prevalence is unknown. This study evaluated the concordance between HbA1c and fasting plasma glucose (FPG) in the diagnosis of diabetes in the general population.

MATERIALS AND METHODS

The study was designed as a population based investigation, with participants being sampled from the Ho Chi Minh City, Vietnam. Blood samples were collected after overnight fasting and analyzed within 4 hours after collection. HbA1c was measured with high pressure liquid chromatography (Arkray Adams, Japan). FPG was measured by the hexokinase method (Advia Autoanalyzer; Bayer Diagnostics, Germany). Diabetes was defined as HbA1c ≥ 6.5% or FPG ≥ 7.0 mmol/L. Prediabetes was classified as HbA1c between 5.7% and 6.4%.

RESULTS

The study included 3523 individuals (2356 women) aged 30 years and above. Based on the HbA1c test, the prevalence of diabetes and prediabetes was 9.7% (95%CI, 8.7-10.7%; n = 342) and 34.6% (33.0-36.2; n = 1219), respectively. Based on the FPG test, the prevalence of diabetes and prediabetes was 6.3% (95%CI, 5.5-7.2%; n = 223) and 12.1% (11.1-13.2; n = 427). Among the 427 individuals identified by FPG as "pre-diabetes", 28.6% were classified as diabetes by HbA1c test. The weighted kappa statistic of concordance between HbA1c and FPG was 0.55, with most of the discordance being in the prediabetes group.

CONCLUSION

These data indicate that there is a significant discordance in the diagnosis of diabetes between FPG and HbA1c measurements, and the discordance could have significant impact on clinical practice. FPG appears to underestimate the burden of undiagnosed diabetes.

A crossover study of the combination therapy of metformin and exenatide or biphasic insulin aspart 30 in overweight or obese patients newly diagnosed with type 2 diabetes mellitus

The aim of the present study was to explore the effects of various combinations of exenatide, metformin (MET) and biphasic insulin aspart 30 (BIA30) on type 2 diabetes mellitus (T2DM). Two hundred overweight or obese patients newly diagnosed with T2DM were evenly randomized into two groups: A (twice daily for all: Phase I, 5 µg exenatide + 0.5 g MET for 4 weeks, then 10 µg exenatide + 0.5 g MET for 8 weeks; Phase II, 0.5 g MET for 12 weeks; Phase III, 0.3-0.4 U/kg/day BIA30 + 0.5 g MET for 12 weeks) and B (Phases I, II, III matched the phases III, II and I in group A). In groups A and B a significant decrease and increase, respectively, in glycated hemoglobin (HbAlc) and body mass index (BMI) was noted during Phase I. A 3.2±0.4-kg decrease in body weight in group A and a 2.6±0.3-kg increase in group B was observed. In Phase II, HbAlc was significantly increased in both groups (P<0.05). In Phase III, the BMI was increased in group A and reduced in group B (P<0.05). There was a 3.8±0.4-kg weight decrease in group B and 4.2±0.5-kg increase in group A (P<0.05). The combination of exenatide and MET promoted weight loss, glycemic control, β-cell function index, C peptide and adiponectin levels. These results suggested that the combination of exenatide and MET is better than the combination of BIA and MET for the therapy of overweight or obese patients newly diagnosed with T2DM.

Chitosan oligosaccharide improves the therapeutic efficacy of sitagliptin for the therapy of Chinese elderly patients with type 2 diabetes mellitus

Sitagliptin improves glycemic control in type 2 diabetes mellitus (T2DM) patients but its side effects are undesirable. Chitosan oligosaccharide (COS) is expected to improve the therapeutic result as a natural product. A total of 200 elderly T2DM patients were evenly assigned into four groups: sitagliptin group (SG), receiving sitagliptin 100 mg/day; COS group (CG), receiving COS 100 mg/day; combination therapy of sitagliptin and COS group (SCG), receiving both sitagliptin and COS 100 mg/day; and placebo group (PG), receiving placebo 100 mg/day. After 42-week therapy, biochemical indices and clinical parameters for the alterations from start points were analyzed. The related molecular mechanism was tested by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot at cell level. Lower risk of hypoglycemia was found in the SCG group when compared with SG and other groups (P<0.05). More patients from the SCG group than other groups attained hemoglobin A1c (HbA1c) reduction >2.5% (P<0.05). Weight reduction of 1.2±0.9, 2.6±0.8, 4.7±1.3, and 0.9±0.6 kg was observed in the patients from SG, CG, SCG, and PG groups, respectively (P<0.05). The combined treatment of COS and sitagliptin presented better therapeutic results by improving insulin sensitivity, lipid profile, adiponectin levels, and glucagon-like peptide 1 and reducing side effects, insulin resistance, HbA1c, body mass index, resistin, tumor necrosis factor (TNF)-α, and C-reactive protein (CRP) (P<0.05). qRT-PCR and Western blot analysis also showed that COS treatment reduced the levels of resistin, TNF-α, and CRP, and increased the level of adiponectin. The combination of COS and sitagliptin provided better glycemic control with fewer side effects and with more weight reduction in the elderly participants with T2DM.

Actinidia chinensis Planch. Improves the Indices of Antioxidant and Anti-Inflammation Status of Type 2 Diabetes Mellitus by Activating Keap1 and Nrf2 via the Upregulation of MicroRNA-424

The fruit juice of Actinidia chinensis Planch. has antioxidant and anti-inflammation properties on patients with type 2 diabetes mellitus (T2DM), but the molecular mechanism was unclear. The patients took the juice and the serum level of antioxidant miR-424, Kelch-like ECH-associated protein 1 (Keap1), erythroid-derived 2-like 2 (Nrf2), and biochemical indices were measured. The juice increased the levels of serum microRNA-424, Keap1, and Nrf2 and reduced the levels of interleukin-1 (IL-1) beta and IL-6 in T2DM patients. The levels of SOD and GSH were higher while the levels of ALT and AST were lower in the patients consuming the juice when compared to the patients without taking the juice. The Spearman rank correlation analysis showed that the serum levels of miR-424 were positively related to Keap1 and Nrf2 levels while Keap1 and Nrf2 levels were positively related to the levels of SOD and GSH and negatively related to IL-1 beta and IL-6. Thus, FJACP improves the indices of antioxidant and anti-inflammation status by activating Keap1 and Nrf2 via the upregulation of miR-424 in the patients with T2DM. This trial is registered with ChiCTR-ONC-17011087 on 04/07/2017.

HbA1c in relation to incident diabetes and diabetes-related complications in non-diabetic adults at baseline

AIMS

We compared the utility of glycated hemoglobin (HbA_1c) and oral glucose tolerance (oGTT) in non-diabetic patients for identifying incident diabetes; all-cause mortality; cardiovascular disease (CVD) mortality; CVD, coronary heart disease (CHD), and ischemic stroke events; and diabetes microvascular complications.

METHODS

Data from a New Zealand community setting were prospectively linked to hospitalization, mortality, pharmaceutical and laboratory test results data. After applying exclusion criteria (prior laboratory diagnosis or history of drug treatment for diabetes or hospitalization for diabetes or CVD event), there were 31,148 adults who had an HbA_1c and 2-h 75g oGTT. HbA_1c was measured by ion-exchange high-performance liquid chromatography, and glucose using a commercial enzymatic method. We compared glycemic measures and outcomes using multivariable Cox proportional hazards regression.

RESULTS

The median follow-up time was 4years (range 0 to 13). The mean age was 57·6years and 53·0% were male. After adjusting for other glycemic measures (fasting glucose, 2-h glucose and/or HbA_1c where relevant) in addition to age, sex, ethnicity and smoking habit, the hazard ratios for incident diabetes and diabetes complications of retinopathy and nephropathy were highest for 2-h glucose levels, followed by HbA_1c and lastly by fasting glucose. However, all-cause mortality and CHD were significantly associated with HbA_1c concentrations only, and ischemic stroke and CVD events with 2-h glucose only. Circulatory complications showed a stronger association with HbA_1c.

CONCLUSION

Apart from neuropathy, HbA_1c showed stronger associations with outcomes compared to fasting glucose and provides a convenient alternative to an oGTT.

2017 Taiwan lipid guidelines for high risk patients

In Taiwan, the prevalence of hyperlipidemia increased due to lifestyle and dietary habit changes. Low density lipoprotein cholesterol (LDL-C) and non-high density lipoprotein cholesterol (non-HDL-C) are all significant predicting factors of coronary artery disease in Taiwan. We recognized that lipid control is especially important in patients with existed atherosclerotic cardiovascular diseases (ASCVD), including coronary artery disease (CAD), ischemic stroke and peripheral arterial disease (PAD). Because the risk of ASCVD is high in patients with diabetes mellitus (DM), chronic kidney disease (CKD) and familial hypercholesterolemia (FH), lipid control is also necessary in these patients. Lifestyle modification is the first step to control lipid. Weight reduction, regular physical exercise and limitation of alcohol intake all reduce triglyceride (TG) levels. Lipid-lowering drugs include HMG-CoA reductase inhibitors (statins), cholesterol absorption inhibitors (ezetimibe), proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, nicotinic acids (niacin), fibric acids derivatives (fibrates), and long-chain omega-3 fatty acids. Statin is usually the first line therapy. Combination therapy with statin and other lipid-lowering agents may be considered in some clinical settings. For patients with acute coronary syndrome (ACS) and stable CAD, LDL-C < 70 mg/dL is the major target. A lower target of LDL-C <55 mg/dL can be considered in ACS patients with DM. After treating LDL-C to target, non-HDL-C can be considered as a secondary target for patients with TG ≥ 200 mg/dL. The suggested non-HDL-C target is < 100 mg/dL in ACS and CAD patients. For patients with ischemic stroke or transient ischemic attack presumed to be of atherosclerotic origin, statin therapy is beneficial and LDL-C < 100 mg/dL is the suggested target. For patients with symptomatic carotid stenosis or intracranial arterial stenosis, in addition to antiplatelets and blood pressure control, LDL-C should be lowered to < 100 mg/dL. Statin is necessary for DM patients with CV disease and the LDL-C target is < 70 mg/dL. For diabetic patients who are ≥ 40 years of age, or who are < 40 years of age but have additional CV risk factors, the LDL-C target should be < 100 mg/dL. After achieving LDL-C target, combination of other lipid-lowering agents with statin is reasonable to attain TG < 150 mg/dL and HDL-C >40 in men and >50 mg/dL in women in DM. LDL-C increased CV risk in patients with CKD. In adults with glomerular filtration rate (GFR) < 60 mL/min/1.73m² without chronic dialysis (CKD stage 3-5), statin therapy should be initiated if LDL-C ≥ 100 mg/dL. Ezetimibe can be added to statin to consolidate the CV protection in CKD patients. Mutations in LDL receptor, apolipoprotein B and PCSK9 genes are the common causes of FH. Diagnosis of FH usually depends on family history, clinical history of premature CAD, physical findings of xanthoma or corneal arcus and high levels of LDL-C. In addition to conventional lipid lowering therapies, adjunctive treatment with mipomersen, lomitapide, or PCSK9 inhibitors become necessary to further reduce LDL-C in patients with FH. Overall, these recommendations are to help the health care professionals in Taiwan to treat hyperlipidemia with current scientific evidences. We hope the prescription rate of lipid lowering drugs and control rate of hyperlipidemia in high risk patients could be increased by implementation of the clinical guidelines. The major purpose is to improve clinical outcomes of these high risk patients through the control of hyperlipidemia.

Diabetes diagnostic thresholds of the glycated hemoglobin A1c and fasting plasma glucose levels considering the 5-year incidence of retinopathy

AIMS

As retinopathy is used as a defining threshold of diabetes, we assessed the glycated hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) values associated with an increased risk of 5-year incidence of retinopathy.

METHODS

We studied HbA1c, FPG, and optic fundus findings of 2605 individuals without previously diagnosed diabetes annually during a 5-year period. Retinopathy was examined using non-mydriatic, 45° digital fundus photography. Baseline levels were stratified as <5.3 [34], 5.3-5.6 [34-38], 5.7-6.0 [39-42], 6.1-6.4 [43-47], and ⩾6.5% [48mmol/mol] for HbA1c and <5.0, 5.0-5.5, 5.6-6.0, 6.1-6.9, and ⩾7.0mmol/L for FPG. Cox proportional hazard models were used to analyze hazard ratios (HRs) associated with HbA1c or FPG for incident retinopathy.

RESULTS

During a total of 11845 person-years, we identified 50 (1.9%) cases of incident retinopathy. The adjusted HRs for incident retinopathy associated with a one-standard deviation increase in HbA1c and FPG were 1.2 (95% confidence intervals: 1.1-1.4) and 1.2 (1.1-1.4), respectively. These HRs were significantly higher for a HbA1c level ⩾6.5% (48mmol/mol) (3.4 [1.1-10.2]) or FPG level ⩾7.0mmol/L (3.6 [1.1-11.6]) than for a HbA1c level <5.3% (34mmol/mol) or FPG level <5.0mmol/L.

CONCLUSIONS

A HbA1c value of 6.5% (48mmol/mol) and FPG value of 7.0mmol/L might be proper as diabetes diagnostic thresholds that indicate a high risk of future retinopathy.

Reanalysis and External Validation of a Decision Tree Model for Detecting Unrecognized Diabetes in Rural Chinese Individuals

We reanalyzed previous data to develop a more simplified decision tree model as a screening tool for unrecognized diabetes, using basic information in Beijing community health records. Then, the model was validated in another rural town. Only three non-laboratory-based risk factors (age, BMI, and presence of hypertension) with fewer branches were used in the new model. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve (AUC) for detecting diabetes were calculated. The AUC values in internal and external validation groups were 0.708 and 0.629, respectively. Subjects with high risk of diabetes had significantly higher HOMA-IR, but no significant difference in HOMA-B was observed. This simple tool will help general practitioners and residents assess the risk of diabetes quickly and easily. This study also validates the strong associations of insulin resistance and early stage of diabetes, suggesting that more attention should be paid to the current model in rural Chinese adult populations.

Glucose: archetypal biomarker in diabetes diagnosis, clinical management and research

The clinical utility of diabetes biomarkers can be considered in terms of diagnosis, management and prediction of long-term vascular complications. Glucose satisfies all of these requirements. Thresholds of hyperglycemia diagnostic of diabetes reflect inflections that confer a risk of developing long-term microvascular complications. Degrees of hyperglycemia (impaired fasting glucose, impaired glucose tolerance) that lie below the diagnostic threshold for diabetes identify individuals at risk of progression to diabetes and/or development of atherothrombotic cardiovascular disease. Self-measured glucose levels usefully complement hemoglobin A1c levels to guide daily management decisions. Continuous glucose monitoring provides detailed real-time data that is of value in clinical decision making, assessing response to new diabetes drugs and the development of closed-loop artificial pancreas technology.

Evidence for current diagnostic criteria of diabetes mellitus

Diabetes mellitus is a non-communicable metabolic derangement afflicting several millions of individuals globally. It is associated with several micro and macrovascular complications and is also a leading cause of mortality. The unresolved issue is that of definition of the diagnostic threshold for diabetes. The World Health Organization and the American Diabetes Association (ADA) have laid down several diagnostic criteria for diagnosing diabetes and prediabetes based on the accumulating body of evidence.This review has attempted to analyse the scientific evidence supporting the justification of these differing criteria. The evidence for diagnosing diabetes is strong, and there is a concordance between the two professional bodies. The controversy arises when describing the normal lower limit of fasting plasma glucose (FPG) with little evidence favouring the reduction of the FPG by the ADA. Several studies have also shown the development of complications specific for diabetes in patients with prediabetes as defined by the current criteria though there is a significant overlap of such prevalence in individuals with normoglycemia. Large multinational longitudinal prospective studies involving subjects without diabetes and retinopathy at baseline will ideally help identify the threshold of glycemic measurements for future development of diabetes and its complications.

Effects of the WHO 1985 criteria and the proposed new diagnostic criteria on the prevalence of diabetes in an elderly population

Population data suggest that a fasting blood glucose level of ≥6.1 mmol/l corresponds best to a two-hour blood glucose level of ≥11.1 mmol/l, which is associated with an increased risk of developing microvascular complications. The proposed new criteria, and the WHO 1985 criteria for diabetes, were applied in an elderly population, which underwent a two-hour oral glucose tolerance test. The prevalence of diabetes was higher when the proposed new criteria were used than when the old criteria were used. In calculating the prevalence of diabetes, the fasting blood glucose ≥6.1 mmol/l corresponded better to the combination of fasting and/or two-hour values than did fasting blood glucose ≥6.7 mmol/l. The prevalence obtained by using either of these fasting values alone or in combination with two-hour values corresponded poorly to that obtained by using mere two-hour blood glucose values.