Glycated haemoglobin A1c for diagnosing diabetes in Chinese population: cross sectional epidemiological survey

Influence of High-Altitude Residential History on Optimal HbA1c Cutoff for Detecting Abnormal Glucose Metabolism

Aims: To explore the influence of recent high-altitude residential history on the optimal cutoff of glycosylated hemoglobin (HbA1c) for detecting abnormal glucose metabolism. Methods: The study included 505 self-reported healthy Han participants of age 18-65 years, recruited in Chengdu and categorized based on recent (within 3 months) high-altitude (>2,500 m) residential history. The 1999 WHO criteria was used as the gold standard for defining prediabetes and diabetes. HbA1c test performance was assessed using receiver operating characteristic curve, with the optimal cutoff determined by Maximum Youden index. Propensity score matching with 0.02 calipers and nearest neighbor method was used to balance confounding factors between groups. Results: Of the participants, 238 (47.13%) were populations with recent high-altitude residential history (HA group), and 267 (52.87%) were low-altitude dwellers (LA group). The HA group had slightly higher HbA1c levels (p > 0.05) and higher erythrocyte and hemoglobin levels (p < 0.05), compared to the LA group. Weak correlations between prediabetes and HbA1c levels were observed in the HA group (rs = 0.21, p < 0.05) and the LA group (rs = 0.07, p = 0.25). The optimal cutoff for the detection of diabetes was 6.5% (area under the curve [AUC] 0.94) in the HA group and 5.9% (AUC 0.97) in the LA group, which remained unchanged after adjustment for confounders. Conclusions: The optimal cutoff of HbA1c for the detection of diabetes in populations with recent history of living at high altitude was higher than that in general populations living at low altitude, and the diagnostic value of HbA1c for prediabetes was also inadequate.

Optimal Glycated Hemoglobin Cutoff for Diagnosis of Diabetes and Prediabetes in Chinese Breast Cancer Women

Purpose

Glycated hemoglobin (HbA1c) is widely used in diabetes management and now recommended for diagnosis and risk assessment. Our research focused on investigating the optimal cutoff points of HbA1c for diagnosis of diabetes and prediabetes in Chinese breast cancer women, aiming to enhance early detection and tailor treatment strategies.

Patients and Methods

This study involved 309 breast cancer women without diabetes history in China. Patients were categorized into groups of newly diagnosed diabetes, prediabetes, and normal glucose tolerance using oral glucose tolerance test (OGTT) according to the 2010 ADA criteria. HbA1c data were collected from all patients. Receiver operating characteristic (ROC) curve analysis was used to assess the effectiveness of the HbA1c screening.

Results

Among the 309 breast cancer women without diabetes history, 96 (31.0%) were identified with diabetes and 130 (42.1%) had prediabetes according to OGTT, and the incidence of normal glucose tolerance was only 26.9% (83). ROC curve analysis, using OGTT as a reference, revealed that the area under the curve of 0.903 (P<0.001, 95% CI, 0.867-0.938) for HbA1c alone, indicating high accuracy. The optimal HbA1c cutoff for identifying diabetes was determined to be 6.0%, with a sensitivity of 78.1% and specificity of 86.4%. For prediabetes, the ROC curve for HbA1c alone showed that the area under the ROC curve of 0.703 (P<0.001, 95% CI, 0.632-0.774), with an optimal cutoff of 5.5% (sensitivity of 76.9% and specificity of 51.8%).

Conclusion

The prevalence of undiagnosed diabetes is very high in breast cancer women without diabetes history in China. The optimal cutoff points of HbA1c for identifying diabetes and prediabetes are 6.0% and 5.5% in Chinese breast cancer women, respectively.

Comparing glycemic traits in defining diabetes among rural Chinese older adults

BACKGROUND

We sought to identify the optimal cut-off of glycated hemoglobin (HbA1c) for defining diabetes and to assess the agreements of fasting plasma glucose (FPG), fasting serum glucose (FSG), and HbA1c in defining diabetes among rural older adults in China.

METHODS

This population-based cross-sectional study included 3547 participants (age ≥61 years, 57.8% women) from the Multidomain Interventions to Delay Dementia and Disability in Rural China from 2018-2019; of these, 3122 had no previously diagnosed diabetes. We identified the optimal cut-off of HbA1c against FPG ≥7.0 mmol/L for defining diabetes by using receiver operating characteristic curve and Youden index. The agreements of FPG, FSG, and HbA1c in defining diabetes were assessed using kappa statistics.

RESULTS

Among participants without previously diagnosed diabetes (n = 3122), the optimal HbA1c cut-off for defining diabetes was 6.5% (48 mmol/mol), with the sensitivity of 88.9%, specificity of 93.7%, and Youden index of 0.825. The correlation coefficients were 0.845 between FPG and FSG, 0.574 between FPG and HbA1c, and 0.529 between FSG and HbA1c in the total sample (n = 3547). The kappa statistic for defining diabetes was 0.962 between FSG and FPG, and 0.812 between HbA1c and FPG.

CONCLUSIONS

The optimal cut-off of HbA1c for diagnosing diabetes against FPG >7.0 mmol/L is ≥6.5% in Chinese rural-dwelling older adults. The agreement in defining diabetes using FPG, FSG, and HbA1c is nearly perfect. These results have relevant implications for diabetes research and clinical practice among older adults in China.

CLINICAL TRIAL REGISTRATION

The protocol of MIND-China was registered in the Chinese Clinical Trial Registry (ChiCTR, www.chictr.org.cn; registration no.: ChiCTR1800017758).

The clinical significance of serum HbA1c to diagnose diabetes mellitus during acute pancreatitis

AIMS

To investigate the prevalence of diabetes mellitus (DM) in acute pancreatitis (AP) patients and to explore the extent to which inflammatory stress affects plasma glucose (PG) levels in AP patients.

METHODS

A retrospective analysis of 2163 AP patients was performed. The PG differences among AP patients under differing pancreatic necrosis conditions and inflammation severity were compared. Receiver operating characteristic curves were used to assess whether fasting PG in the inflammatory stage of AP might be used for DM screening.

RESULTS

The overall DM prevalence was 19.97% in AP patients, 32.41% of whom had newly diagnosed DM (based on HbA1c levels in patients who self-reported no DM). The DM prevalence was 46.93% in hyperlipidemic AP patients, 44.14% of whom had newly diagnosed DM. In patients with and without pancreatic necrosis, the optimal PG thresholds for the screening of newly diagnosed DM were 10.40 mmol/L and 8.21 mmol/L, respectively, with an AUC of 0.959 ± 0.034 (P < 0.001) and 0.972 ± 0.006 (P < 0.001), respectively.

CONCLUSIONS

For hospitalized AP patients and fasting PG levels exceeding 10 mmol/L (with necrosis) or 8 mmol/L (without necrosis) (P < 0.001), HbA1c testing is recommended to investigate the presence of comorbid undiagnosed DM.

Evaluating the predictive value of diabetes mellitus diagnosed according to the Chinese guidelines (2020 edition) for cardiovascular events

OBJECTIVE

Chinese diabetes society has published the new diagnostic criteria for diabetes in China (2020 edition). We aimed to investigate the predictive value of new diabetes-diagnosed criteria for cardiovascular diseases (CVD).

METHODS

A total of 5884 individuals from the China Health and Retirement Longitudinal Study in 2011 and 2018 were enrolled. Baseline characteristics and outcome data were compared. The association between diabetes diagnosed by two criteria and future CVD was identified by Kaplan-Meier curves, Cox regression analyses, and receiver-operating characteristic analyses. Delong's test was conducted to compare the predictive value for future CVD between diabetes diagnosed by the 2020 edition and diabetes diagnosed by the previous version.

RESULTS

After multivariate adjustment, both diabetes diagnosed by the 2020 edition and diabetes diagnosed by the previous edition is associated with CVD (HR 1.607, 95% CI 1.221-2.115, P < 0.001; HR 1.244, 95% CI 1.060-1.460, P = 0.007, respectively). The Kaplan-Meier analysis indicated that diabetes patients have more cardiovascular risk (log-rank P<0.001). Moreover, diabetes diagnosed in the 2020 edition illustrated an area under the curve (AUC) of 0.673 for predicting CVD, while diabetes diagnosed in the previous edition showed an AUC of 0.638 (DeLong's test P<0.01).

CONCLUSION

Diabetes diagnosis criteria (2020 edition) in China had better performance in predicting cardiovascular diseases than the previous edition.

[Effectiveness of different screening strategies for type 2 diabete on preventing cardiovascular diseases in a community-based Chinese population using a decision-analytic Markov model]

OBJECTIVE

To evaluate the effectiveness of different screening strategies for type 2 diabetes to prevent cardiovascular disease in a community-based Chinese population from economically developed areas based on the Chinese electronic health records research in Yinzhou (CHERRY) study.

METHODS

A Markov model was used to simulate different systematic diabetes screening strategies, including: (1) screening among Chinese adults aged 40-70 years recommended by the 2020 Chinese Guideline for the prevention and Treatment of Type 2 Diabetes (Strategy 1); (2) screening among Chinese adults aged 35 to 70 years recommended by the 2022 American Diabetes Association Standard of Medical Care in Diabetes (Strategy 2); and (3) screening among Chinese adults aged 35-70 years with overweight or obesity recommended by the 2021 United States Preventive Services Task Force Recommendation Statement on Screening for Prediabetes and Type 2 Diabetes (Strategy 3). According to the guidelines, individuals who were screened positively (fasting plasma glucose ≥ 7.0 mmol/L) would be introduced to intensive glycemic targets management (glycated hemoglobin < 7.0%).The Markov model simulated different screening scenarios for ten years (cycles) with parameters mainly from the CHERRY study or published literature. Number of cardiovascular disease events or deaths could be prevented and number needed to screen (NNS) were calculated to compare the effectiveness of the different strategies. One-way sensitivity analysis on the sensitivity of screening methods and probabilistic sensitivity analysis on uncertainties of diabetes incidence, the sensitivity of screening methods, and intensive glycemic management effects were conducted.

RESULTS

Totally 289 245 Chinese adults aged 35-70 years without cardiovascular diseases or diagnosed diabetes at baseline were enrolled. In terms of the number of cardiovascular disease events could be prevented, Strategy 1 for systematic diabetes screening among the adults aged 35-70 years was 222 (95%UI: 180-264), Strategy 2 for systematic diabetes screening among the adults aged 40-70 years was 227 (95%UI: 185-271), and Strategy 3 for systematic diabetes screening among the adults aged 35-70 years with obesity or overweight (body mass index ≥ 24 kg/m²) was 131 (95%UI: 98-164), compared with opportunistic screening. NNS per cardiovascular disease event for the strategies 1, 2 and 3 were 1 184 (95%UI: 994-1 456), 1 274 (95%UI: 1 067-1 564) and 814 (95%UI: 649-1 091), respectively. Compared with Strategy 1, NNS per cardiovascular disease event for Strategy 2 increased by 90 (95%UI: -197-381) with similar effectiveness of cardiovascular prevention; however, NNS per cardiovascular disease event for Strategy 3 was reduced by 460 (95%UI: 185-724) in contrast to the Strategy 2, suggesting that the Strategy 3 was more efficient. The results were consistent in multiple sensitivity analyses.

CONCLUSION

Systematic screening for diabetes based on the latest guidelines in economically developed areas of China can reduce cardiovascular events and deaths. However, merely lowering the starting age of screening from 40 to 35 years seems ineffective for preventing cardiovascular disease, while screening strategy for Chinese adults aged 35-70 years with overweight or obesity is recommended to improve efficiency.

Characteristics of participants who take up screening tests for diabetes and lipid disorders: a systematic review

OBJECTIVES

To perform a systematic review on the characteristics of participants who attended screening programmes with blood glucose tests, lipid profiles or a combination of them, respectively.

DESIGN

Systematic review following the Meta-analysis Of Observational Studies in Epidemiology checklist.

DATA SOURCES

PubMed and Medline databases for English literature from 1 January 2000 to 1 April 2020.

ELIGIBILITY CRITERIA

Original observational studies that reported baseline characteristics of apparently healthy adult participants screening for diabetes and lipid disorders were included in this review.

DATA EXTRACTION

We examined their sociodemographic characteristics, including age, gender, body mass index (BMI) and lifestyle habits. The quality of the included articles was evaluated by the Appraisal of Cross-sectional Studies.

RESULTS

A total of 33 articles involving 38 studies in 22 countries were included and analysed in this systematic review. Overall, there was a higher participation rate among subjects who were female in all screening modalities (female vs male: 46.6%-63.9% vs 36.1%-53.4% for diabetes screening; 48.8%-58.4% vs 41.6%-51.2% for lipid screening; and 36.4%-76.8% vs 23.2%-63.6% for screening offering both). Compared with the BMI standard from the WHO, participants in lipid screening had lower BMI (male: 23.8 kg/m2 vs 24.2 kg/m2, p<0.01; female: 22.3 kg/m2 vs 23.6 kg/m2, p<0.01). Furthermore, it is less likely for individuals of lower socioeconomic status to participate in diabetes or lipid screening in developed areas.

CONCLUSIONS

We identified that individuals from lower socioeconomic groups were less likely to take up programmes for diabetes and/or lipid screening in developed areas. These populations are also likely to be at higher risk of non-communicable diseases. Future studies should investigate the barriers and facilitators of screening among non-participants, where targeted interventions to enhance their screening uptake are warranted.

Effectiveness and Acceptability of a Nutrition Intervention Targeting Chinese Adult Immigrants With Type 2 Diabetes in Canada: A Study Using Mixed Methods Analysis

OBJECTIVES

Although culturally tailored diabetes treatment is recommended, there is a lack of relevant dietary resources for the Chinese population in Canada. In this study we assessed the feasibility and efficacy of a culturally tailored menu plan combined with nutrition education on clinical outcomes, diet quality and qualitative outcomes among Chinese immigrants with type 2 diabetes.

METHODS

Participants were 17 Chinese immigrants living with type 2 diabetes in Edmonton, Alberta, Canada. The design was a 12-week, single-arm intervention that included weekly nutrition education supported by a culturally tailored menu plan with mixed methods evaluation. Diet quality, clinical and other outcomes were assessed pre- and postintervention. One-on-one interviews were conducted postintervention to identify program feasibility and obstacles to adherence.

RESULTS

Waist circumference (mean ± standard deviation: -2.0±2.5 cm; p=0.004), total cholesterol (-21.4±28.2 mg/dL; p=0.007) and low-density lipoprotein cholesterol (-18.4±24.6 mg/dL; p=0.007) were decreased when compared with baseline. No significant change was detected in glycated hemoglobin. Postintervention, the Healthy Eating Index (p=0.01) and diabetes knowledge score (p=0.009) also increased. Participants reported that the program was culturally acceptable, easily understood and feasible to implement. Participants indicated the program helped them to improve their diabetes knowledge, adhere to the dietary guidelines, choose low glycemic index food and read food labels when shopping.

CONCLUSIONS

A flexible, culturally tailored menu plan was a feasible and effective tool for improving diabetes knowledge, diet quality and metabolic outcomes among Chinese immigrants with type 2 diabetes.

The relationship between sex hormones and glycated hemoglobin in a non-diabetic middle-aged and elderly population

BACKGROUND

Sex hormones are strongly linked to the occurrence and development of diabetes, and influence glycated hemoglobin (HbA_1c) levels in diabetic population; but, the relationship between sex hormones and HbA_1c in non-diabetic population remains unknown. This study aimed to explore the extent of influence of sex hormones on HbA_1c levels in non-diabetic population.

METHODS

A total of 1409 non-diabetic subjects, including 601 men and 808 postmenopausal women were recruited from Shanghai community. HbA_1c was detected using high performance liquid chromatography, and hemoglobin level was determined by sodium lauryl sulfate colorimetry. Serum estradiol (E₂), total testosterone (TT), and sex hormone binding globulin (SHBG) were measured by chemiluminescent microparticle immunoassays.

RESULTS

The level of HbA_1c was 5.6 (5.4-5.9) % in all subjects, with 5.6 (5.4-5.8) % in men and 5.7 (5.5-5.9) % in postmenopausal women. After adjusting for age, body mass index (BMI), and hemoglobin, E₂ was positively correlated with HbA_1c in men (r = 0.122, P = .003), and SHBG was inversely correlated with HbA_1c (r = - 0.125, P < .001) in women. Other hormones were not correlated with HbA_1c (all P > .05). Multivariate linear regression analysis showed that, except for traditional factors, such as age, hemoglobin, and BMI, E₂ was another determinant of HbA_1c (standardized β = 0.137, P = .003) in men; besides, in women, SHBG was another determinant of HbA_1c (standardized β = - 0.178, P < .001), except for age and systolic blood pressure.

CONCLUSION

After controlling for confounding factors, two sex hormones, as E₂ and SHBG could influence HbA_1c levels in non-diabetic population.

HbA1c combined with glycated albumin or 1,5-anhydroglucitol improves the efficiency of diabetes screening in a Chinese population

AIMS

This study aimed to evaluate the ability of HbA_1c combined with glycated albumin (GA) or 1,5-anhydroglucitol (1,5-AG) to detect diabetes in residents of Jiangsu, China.

METHODS

The oral glucose tolerance test (OGTT) was performed on 2184 people in Jiangsu. HbA_1c , GA, 1,5-AG and other serum biochemical parameters were measured. Receiver operating characteristic curves were plotted to determine the optimal thresholds of HbA_1c , GA and 1,5-AG according to the Youden index.

RESULTS

(1) The optimal thresholds of HbA_1c , GA and 1,5-AG for the screening of diabetes were ≥45 mmol/mol (6.3%), ≥13.0% and ≤23.0 μg/ml, respectively. (2) The sensitivities of HbA_1c combined with GA and 1,5-AG were both 85%, higher than that of HbA_1c (70%, p < 0.001).

CONCLUSIONS

This study is suitable for cases where plasma glucose is unavailable. Among the residents of Jiangsu, HbA_1c combined with GA or 1,5-AG can improve the sensitivity of diabetes screening, reduce the miss rate and save the use of OGTT. GA and 1,5-AG are superior in individuals with mild glucose metabolism disorder. GA enhances the detection of diabetes in the nonobese, and 1,5-AG enhances the detection in those with hyperuricaemia.

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.

Portable and Intelligent Urine Glucose Analyzer Based on a CdTe QDs@GOx Aerogel Circular Array Sensor

Diabetes is a public health problem characterized by hyperglycemia, high mortality, and morbidity. A simple, rapid, and sensitive glucose detection method for diabetes screening and health self-management of patients with diabetes is of great significance. Therefore, an attractive urine glucose (UG) analyzer with advantages of fastness, sensitivity, and portability was developed. A cadmium telluride quantum dots (CdTe QDs)@glucose oxidase (GOx) aerogel circular array sensor can emit visible red fluorescence when excited by a 365 nm ultraviolet light source inside the analyzer. When urine samples containing glucose were dropped onto the sensor, glucose was oxidized by GOx to produce hydrogen peroxide (H₂O₂), which quenched the red fluorescence of CdTe QDs. The fluorescence images of the sensor were obtained using a CCD camera, and the linear relationship between the glucose concentration and the gray value of the fluorescence image was established. The analyzer shows good sensitivity (LOD, 0.12 mM) with a wide linear range of 0.12-26 mM. Based on the linear relation, the software of the analyzer was written in the C++ language, which can automatically give the gray value of the image and the corresponding glucose concentration. The UG analyzer was used for the detection of a large number clinical samples and compared with a variety of UG test papers, which all showed good detection performance. The novel analyzer we proposed has an important significance in the screening of diabetes and the self-management of diabetic patients.

Metabolite Triplet in Serum Improves the Diagnostic Accuracy of Prediabetes and Diabetes Screening

Large-scale population screenings are not feasible by applying laborious oral glucose tolerance tests, but using fasting blood glucose (FPG) and glycated hemoglobin (HbA_1c), a considerable number of diagnoses are missed. A novel marker is urgently needed to improve the diagnostic accuracy of broad-scale diabetes screening in easy-to-collect blood samples. In this study, by applying a novel knowledge-based, multistage discovery and validation strategy, we scaled down from 108 diabetes-associated metabolites to a diagnostic metabolite triplet (Met-T), namely hexose, 2-hydroxybutyric/2-hydroxyisobutyric acid, and phenylalanine. Met-T showed in two independent cohorts, each comprising healthy controls, prediabetic, and diabetic individuals, distinctly higher diagnostic sensitivities for diabetes screening than FPG alone (>79.6 vs <68%). Missed diagnoses decreased from >32% using fasting plasma glucose down to <20.4%. Combining Met-T and fasting plasma glucose further improved the diagnostic accuracy. Additionally, a positive association of Met-T with future diabetes risk was found (odds ratio: 1.41; p = 1.03 × 10^-6). The results reveal that missed prediabetes and diabetes diagnoses can be markedly reduced by applying Met-T alone or in combination with FPG and it opens perspectives for higher diagnostic accuracy in broad-scale diabetes-screening approaches using easy to collect sample materials.

Diagnostic accuracy of ADA 2020 criteria for undiagnosed diabetes in a Peruvian population

AIMS

To assess the prevalence of undiagnosed diabetes (UDD) and the diagnostic accuracy of the American Diabetes Association (ADA) criteria to detect UDD cases in a Peruvian population.

METHODS

Population-based cross-sectional study. UDD was defined using fasting plasma glucose (FPG), 2-hour post-prandial plasma glucose (2 h-PPG), and glycated hemoglobin (HbA1c) traditional cut-offs. Diagnostic accuracy was estimated using areas under the receiver-operating characteristic (ROC) curve, compared with the combination of oral glucose tolerance test (FPG plus 2 h-PPG) plus HbA1c as gold standard.

RESULTS

1609 subjects were evaluated; mean age 48.2 (SD: 10.6) years, 50.3% were women. A total of 179 (11.3%) subjects were classified as having diabetes, 41.3% of them had UDD. Area under the curve for FPG, 2 h-PPG and HbA1c was 86.5% (95% CI: 81.4-91.6%); 87.2% (95% CI: 82.2-92.2%) and 80.4% (95% CI: 74.8-86.0%), respectively. FPG sensitivity was 73.0%, whereas this value was 74.3% for 2 h-PPG and 60.8% for HbA1c. Of 74 UDD cases, 45 were positive for HbA1c, 54 for FPG and 55 for 2 h-PPG.

CONCLUSIONS

41.3% of people with diabetes do not know their diagnosis. Diagnostic accuracy of FPG and 2 h-PPG was higher than HbA1c. The most sensitive combination of two tests to detect UDD cases was FPG plus 2 h-PPG.

Detection of diabetes and prediabetes using glycosylated hemoglobin in Chinese adults living in Shanghai: A prospective analysis

BACKGROUND

This study aimed to evaluate the discriminative abilities of glycosylated hemoglobin (HbA1c) and to examine the optimal HbA1c cutoff values for diabetes and prediabetes in Chinese adults.

METHODS

Data of a population-based cohort of Chinese adults aged ≥40 years living in Jiading District in Shanghai were used. At baseline, 9389 and 7241 participants were included to identify the optimal HbA1c cutoff values for diabetes and prediabetes, respectively using the 1999 World Health Organization criteria as reference. In addition, the follow-up data on incident diabetes of 4538 participants were used to determine the HbA1c cutoff value for prediabetes using the development of diabetes as reference. The discriminative abilities of HbA1c were evaluated using receiver operating characteristic (ROC) curves, and the optimal cutoff values were determined by Youden's index.

RESULTS

The areas under the ROC curves were 0.849 for diabetes, 0.614 for prediabetes using baseline data, and 0.648 for prediabetes using follow-up data. An HbA1c cutoff value of 6.0% had the largest Youden's index to diagnose diabetes with a sensitivity of 70.2% and a specificity of 87.4%. An HbA1c cutoff value of 5.6% was indicated for prediabetes using both baseline and follow-up data. However, the sensitivity and specificity were both low (55.4% and 61.1% using an oral glucose tolerance test as reference, 64.6% and 57.1% using incident diabetes as reference).

CONCLUSIONS

An HbA1c value ≥6.0% could be used to detect diabetes in Chinese adults aged ≥40 years. However, although an HbA1c value of 5.6% to 5.9% was indicated in this study, the overall discrimination of HbA1c for prediabetes was poor.

Erythrocytosis and Performance of HbA1c in Detecting Diabetes on an Oxygen-Deficient Plateau: A Population-based Study

CONTEXT

The hemoglobin A1c (HbA1c) test is a standard test for diabetes screening and diagnosis.

OBJECTIVE

To evaluate A1c performance for diabetes screening in high-altitude polycythemia compared to a population with a high proportion of people living in an oxygen-deficient environment.

DESIGN

A population-based epidemiological survey was conducted.

SETTING

The cities Lhasa and Shigatse were selected. Volunteers were recruited through educational advertisements about diabetes.

PARTICIPANTS

A total of 1401 Tibetan adults without known diabetes.

INTERVENTIONS

Oral glucose tolerance test (OGTT), HbA1c, and complete blood cell count were performed. Hemoglobin A1c was evaluated using high-performance liquid chromatography, and serum glucose level, using the hexokinase method.

MAIN OUTCOME MEASURES

World Health Organization criteria were used to define diabetes and prediabetes. Hemoglobin A1c test performance was evaluated using receiver operating characteristic analysis.

RESULTS

The participants' mean age was 44.3 ± 15.0 years; 33.3% of the participants were men and 38.6% lived in urban areas. The prediabetes and diabetes prevalence rates were 7.5% and 3.6%, respectively. The optimal HbA1c cutoff for detecting diabetes was 46 mmol/mol (6.4%), with a sensitivity and specificity of 60.8% and 93.6%, respectively. The cutoff for detecting diabetes was 6.7% (50 mmol/mol) in subjects with high-altitude polycythemia (HAPC). The relationship between red blood cell (RBC) counts and HbA1c was significant (P < 0.001), while there was no correlation between hemoglobin (Hb) and HbA1c (P = 0.085). Multiple linear regression analysis showed that after adjusting for age and fasting serum glucose or 2-hour OGTT (OGTT2h) serum glucose, RBC count and not Hb level was an independent risk factor for HbA1c (β = 0.140, P < 0.001).

CONCLUSIONS

The optimal HbA1c cutoff for detecting diabetes was 46 mmol/mol (6.4%) in Tibet. Red blood cell count was an independent risk factor for elevated HbA1c, and HAPC may affect the predictive ability of HbA1c.

A formula based on autonomic test using EZSCAN and anthropometric data for diagnosis of DM in China

Clinical diagnosis of diabetes mellitus (DM) is time-consuming and invasive. This study aimed to investigate the efficacy and accuracy of EZSCAN in detecting impaired glucose tolerance (IGT) and diabetes mellitus (DM) in Chinese population, and explore a diagnosis formula based on an autonomic test using EZSCAN measurement and anthropometric data. Eligible subjects (n = 1547) had the following data collected: those of anthropometric and EZSCAN measurements and biochemical tests including FPG, OGTT, HbA1c, and serum lipid tests. The support vector machine (SVM) algorithm method was used to derive a diagnostic formula. In this study, 452 and 263 subjects were diagnosed with T2DM and IGT, respectively, while 832 had normal glucose tolerance (NGT). The sensitivity rates for the formula were 77.2% for T2DM and 80.4% for IGT. The diagnostic formula was found to correlate strongly with EZSCAN values. The diagnostic formula based on autonomic test and anthropometric data appears to be a convenient and accurate routine screening option in the Chinese population.

Prevalence of Diabetes and Prediabetes in Adults from a Third-Tier City in Eastern China: A Cross-Sectional Study

INTRODUCTION

The aims of this study were to investigate the prevalence of adult diabetes and prediabetes in Bengbu (eastern China) in 2017, and to identify measures that can be taken to reduce the prevalence of diabetes and prediabetes in this region.

METHODS

A stratified cluster random sampling method was used in the study. Two sampling sites were randomly selected from each of the four districts of Bengbu City, and all permanent residents (resident for ≥ 5 years) at all eight sampling sites aged 18 years or above were cluster sampled, which led to the sampling of 3388 adults. After screening, a total of 3144 respondents were enrolled in the study. The t test was utilized to compare the mean parameter values of the males and the females, and variance analysis was employed to compare the mean values of the nondiabetic, prediabetic, and diabetic groups. The chi-squared test was used to compare rates. Logistic regression was used for multivariate analysis, and the statistical significance level α was set to 0.05.

RESULTS

The mean ages of the male and female groups were 51.1 ± 15.7 and 49.4 ± 15.1 years, respectively (p < 0.05). The diabetes prevalence in adults was 11.5% (8.4% after standardization), while the prevalence of prediabetes in adults was 32.0% (27.6% after standardization). The prevalence of diabetes and that of prediabetes gradually increased with age (both p < 0.05). Older age, hypertension, overweight status, obesity, central obesity, current smoker status, low serum high-density lipoprotein level, and high serum low-density lipoprotein level were all significantly associated with a higher risk of diabetes (p < 0.05).

CONCLUSION

The prevalence of diabetes and that of prediabetes in adults in Bengbu City remain high. Intervention aimed at reducing the occurrence of diabetic complications and preventing prediabetes from further development is urgently required.

Efficacy of urinary glucose for diabetes screening: a reconsideration

AIMS

Previous studies indicated that urinary glucose (UG) had a limited efficacy in diabetes screening. This study was designed to have a re-evaluation of its efficacy, taking into consideration the collection method of urine and the measurement approach for UG among Chinese adults.

METHODS

This cross-sectional study enrolled a total of 7689 participants without known diabetes, who were fasted and asked to empty bladders before a 75 g glucose loading. Urine was collected 2 h post glucose loading, and UG was measured using quantitative and qualitative approaches. The efficacy of UG in detecting diabetes was assessed by the receiver operating characteristic (ROC) curve.

RESULTS

The area under the ROC curve was 0.89 for quantitative UG and 0.87 for qualitative UG. Quantitative UG was positively correlated with fasting plasma glucose (FPG) and 2 h plasma glucose (2 h PG) (r = 0.55 and 0.56, respectively, both P < 0.001). Quantitative UG displayed a sensitivity of 82.9% and a specificity of 84.7% in detecting diabetes at the corresponding optimal cutoff of 130 mg. Qualitative UG exhibited a sensitivity of 80.2% and a specificity of 85.6% at the optimal cutoff of glycosuria + 1. In addition, the sensitivity of both quantitative and qualitative UG was significantly higher than that of HbA1c (≥ 6.5%) (P < 0.001) and had a comparable sensitivity to 2 h PG (≥ 11.1 mmol/L) (P = 0.493).

CONCLUSIONS

UG, either quantitatively or qualitatively measured at 2 h post glucose loading, was effective in diabetes screening. This indicates that UG is a feasible approach for diabetes screening.

Identification of Newly Diagnosed Diabetes and Prediabetes Using Fasting Plasma Glucose and Urinary Glucose in a Chinese Population: A Multicenter Cross-Sectional Study

Background

Although fasting plasma glucose (FPG) has been highly recommended as the sole test for diabetes screening, the efficacy of FPG alone for diabetes screening is potentially limited due to its low sensitivity. The aim of this study was to improve the efficacy of FPG for diabetes screening using urinary glucose (UG).

Methods

This study was initiated on November 12, 2015, and ended on June 28, 2016. A representative sample of individuals aged between 18 and 65 years, with no history of diabetes, from 6 cities in Jiangsu Province participated in this study. A 75-g oral glucose tolerance test was used to diagnose diabetes. All urine samples were collected within 2 h of oral glucose loading to measure UG. Partial correlation analyses were used to evaluate the associations between UG and other glycemic variables, including FPG, 2-h plasma glucose (2h-PG), and glycated hemoglobin A1c, after adjustment for age. The performance of UG was evaluated using a receiver operating characteristic (ROC) curve analysis.

Results

Of the 7485 individuals included, 8% were newly diagnosed with diabetes and 48.7% had prediabetes. The areas under the ROC curves for UG were 0.75 for estimation of 2h-PG ≥7.8 mmol/L and 0.90 for 2h-PG ≥11.1 mmol/L, respectively. The sensitivity and specificity of UG were 52.3% and 87.8%, respectively, for 2h-PG ≥7.8 mmol/L (cutoff point ≥130 mg), and 83.5% and 87.5%, respectively, for 2h-PG ≥11.1 mmol/L (cutoff point ≥178.5 mg). The combination of FPG and UG demonstrated a significantly higher sensitivity than that of FPG alone for the identification of diabetes ([483/597] 80.9% vs. [335/597] 56.1%, χ² = 85.0, P < 0.001) and glucose abnormalities ([2643/4242] 62.3% vs. [2365/4242] 55.8%, χ² = 37.7, P < 0.001).

Conclusions

The combination of UG and FPG substantially improves the efficacy of using FPG alone for diabetes screening; this combination might be a practical screening tool and is worth being recommended in the future.

Optimal hemoglobin A1C cutoff value for diabetes mellitus and pre-diabetes in Pudong New Area, Shanghai, China

AIMS

Due to the diversity of the Chinese population, it requires considerable research to evaluate HbA1c diagnostic threshold for diagnosis of hyperglycemia.

METHODS

We included 7909 subjects aged ≥15 without known diabetes from the baseline of Pudong community cohort in 2013. Participants took oral glucose tolerance test (OGTT) and HbA1c assay. Receiver operating characteristic curve determined the HbA1c threshold in the diagnosis of hyperglycemia.

RESULTS

The optimal HbA1C threshold for diagnosing newly diagnosed diabetes (NDD) and pre-diabetes in this population was 6.0% (AUC=0.798, 95%CI: 0.779-0.818) and 5.6% (AUC=0.655, 95%CI: 0.638-0.671). When compared with elderly age group (≥70 years), HbA1c for detecting NDD performed better in youth (15-39 years: P=0.003, 40-49 years: P<0.001). There were 13.81% and 13.34% of participants would be newly detected as NDD and pre-diabetes via HbA1c criteria; meanwhile 3.20% and 15.52% diagnosed as NDD and pre-diabetes by OGTT criteria would be missed diagnosis.

CONCLUSIONS

The optimal HbA1c thresholds for NDD and pre-diabetes were lower than ADA criteria. It is necessary to carefully consider whether choose HbA1c as a diagnostic criterion or combine two diagnostic standards. Age-specific diagnostic thresholds should be considered when HbA1c was recommended as diagnostic standard.

Sex and age discrepancy of HbA1c and fetal hemoglobin determined by HPLC in a large Chinese Han population

BACKGROUND

It is accepted that HbA1c is an effective indicator to evaluate glycemic control. Fetal hemoglobin (HbF) is seldom measured because traditional detection is inconvenient. In this regard, there may be an advantage in using HPLC autoanalysis of HbA1c as a surrogate method for HbF detection. The aim of the present study was to explore the distribution of HbA1c and HbF in a large Chinese Han population.

METHODS

In all, 70 553 blood samples were collected between January 2012 and June 2016. Study subjects were inpatients undergoing routine medical care and were divided into four groups based on age: Group A, 20-39 years; Group B, 40-59 years; Group C, 60-79 years; and Group D, ≥80 years. Blood HbA1c and HbF concentrations were measured by HPLC using a Tosho Bioscience (Tokyo, Japan) G8 analyzer.

RESULTS

There was a positive association between HbA1c and age, and a negative association between HbF and age. The concentration range of HbF was narrow and HbF concentrations were significantly higher in females than males, regardless of age (median 0.7% vs 0.6%, respectively; P < 0.0001). There was a low degree of correlation between HbF and HbA1c (r = 0.181, P < 0.0001). Although median HbA1c levels were higher in male than female subjects aged 20-59 years (5.5% vs 5.4%, respectively, in Group A; 5.9% vs 5.8%, respectively in Group B), in the 60-79 years group, HbA1c levels were lower in males than females (6.1% vs 6.2%, respectively; P < 0.0001).

CONCLUSIONS

The data suggest that sex and age should be considered in clinical interpretation of HbA1c.

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.

Causal Association of Overall Obesity and Abdominal Obesity with Type 2 Diabetes: A Mendelian Randomization Analysis

OBJECTIVE

This study aimed to compare the causal effect of overall obesity and abdominal obesity on type 2 diabetes among Chinese Han individuals.

METHODS

The causal relationship of BMI and waist-to-hip ratio (WHR) with the risk of glucose deterioration and glycemic traits was compared using two different genetic instruments based on 30 BMI loci and 6 WHR loci with Mendelian randomization (MR) in three prospective cohorts (n = 6,476).

RESULTS

Each 1-SD genetically instrumented higher WHR was associated with a 65.7% higher risk of glucose deterioration (95% CI = 1.069-2.569, P = 0.024), whereas no significant association of BMI with glucose deterioration was observed. Furthermore, a causal relationship was found only between BMI and homeostatic model assessment β-cell function (HOMA-B) (β = 0.143, P = 0.001), and there was a nominal association with Stumvoll second-phase insulin secretion traits (β = 0.074, P = 0.022). The significance level did not persist in sensitivity analyses, except in the causal estimate of WHR on the Gutt index in MR-Egger (β = -0.379, P = 0.022) and the causal estimate of BMI on homeostatic model assessment β-cell function in weighted median MR (β = 0.128, P = 0.017).

CONCLUSIONS

The data from this study support the potential causal relationship between abdominal obesity and hyperglycemia, which may be driven by aggravated insulin resistance, in contrast with the potential causal relationship between overall obesity and insulin secretion.

Diastolic dysfunction predicts the risk of contrast-induced nephropathy and outcome post-emergency percutaneous coronary intervention in AMI patients with preserved ejection fraction

Patients with acute myocardial infarction (AMI) and reduced left ventricular ejection fraction (LVEF) are at high risk of contrast-induced nephropathy (CIN). However, the risk factors of CIN in AMI patients with preserved LVEF remain largely unknown now. The present study explored the relationship between LV diastolic function and CIN in this patient cohort. The present prospective cohort study enrolled 379 AMI patients with preserved LVEF (≥ 50%) who underwent emergency percutaneous coronary interventions (PCI). Transthoracic echocardiography was performed before PCI using a portable echocardiography system. Diastolic function was graded as normal, indeterminate and diastolic dysfunction according to the current recommendation of the American Society of Echocardiography and the European Association of Cardiovascular Imaging. A total of 88 patients (23.2%) developed CIN. Multivariate logistic regression analysis showed that both diastolic dysfunction (DD) and the mitral E velocity to mitral annular tissue Doppler E' velocity ratio (E/E') were independent predictors of CIN (P < 0.001). Other independent risk factors of CIN included increased Mehran score, ST-segment-elevation myocardial infarction, higher HbA1c and left anterior descending lesion, as well as the use of diuretics. Multivariate Cox regression analysis found that CIN, DD, higher N-terminal pro-B-type natriuretic peptide and HbA1c were independent predictors of MACE 2 years after AMI. Diastolic dysfunction determined before emergency PCI is linked with increased risk of CIN in AMI patients with preserved LVEF. CIN and diastolic dysfunction are independent predictors of MACE at 2 years in this patient cohort.

Verification of a novel point-of-care HbA1c device in real world clinical practice by comparison to three high performance liquid chromatography instruments

Introduction

A real world clinical study was designed and conducted to evaluate the performance of a novel point-of-care device for determination of glycated haemoglobin A_1c (HbA_1c), A1C EZ 2.0, in daily clinical practice.

Materials and methods

Five hundred and fourteen subjects were included in this study, and divided into three groups. HbA_1c was measured by A1C EZ 2.0 and three different high performance liquid chromatography (HPLC) devices: Bio-Rad Variant II Turbo, Tosoh HLC-723 G8 and Premier Hb9210 separately. Precision of A1C EZ 2.0 was also evaluated.

Results

Results obtained from A1C EZ 2.0 and all HPLC devices are correlated. Passing-Bablok regression analysis shows the equation of A1C EZ 2.0 results against the mean of HPLC devices with corresponding 95% confidence intervals (95% CI) for the intercept and slope is y = 0.10 (- 0.17 to 0.10) + 1.00 (1.00 to 1.04) x. Bland-Altman difference plot shows that the mean relative difference between A1C EZ 2.0 and Variant II Turbo, G8, Hb9210 and all HPLC results is 2.5%, 0.6%, 0.4% and 1.1%, respectively. In addition, 121 pairs of results determined by using both venous and capillary blood prove that the difference of two kinds of blood sample causes no notable variation when measured by A1C EZ 2.0. Precision study gives 2.3% and 1.9% of total coefficient of variation for normal and abnormal HbA_1c sample in A1C EZ 2.0.

Conclusions

HbA_1c values measured by A1C EZ 2.0 were in good accordance with the results obtained with the reference HPLC devices.

Diabetes in China: Epidemiology and Genetic Risk Factors and Their Clinical Utility in Personalized Medication

The incidence of type 2 diabetes (T2D) has rapidly increased over recent decades, and T2D has become a leading public health challenge in China. Compared with European descents, Chinese patients with T2D are diagnosed at a relatively young age and low BMI. A better understanding of the factors contributing to the diabetes epidemic is crucial for determining future prevention and intervention programs. In addition to environmental factors, genetic factors contribute substantially to the development of T2D. To date, more than 100 susceptibility loci for T2D have been identified. Individually, most T2D genetic variants have a small effect size (10-20% increased risk for T2D per risk allele); however, a genetic risk score that combines multiple T2D loci could be used to predict the risk of T2D and to identify individuals who are at a high risk. Furthermore, individualized antidiabetes treatment should be a top priority to prevent complications and mortality. In this article, we review the epidemiological trends and recent progress in the understanding of T2D genetic etiology and further discuss personalized medicine involved in the treatment of T2D.

Analysis of Changes in Retinal Thickness in Type 2 Diabetes without Diabetic Retinopathy

OBJECTIVE

To examine the changes in retinal thickness of patients with diabetes without DR.

DESIGNS

A randomization, crossover, retrospective practice.

PARTICIPANTS

43 diabetic patients and 43 ethnic-, age-, and sex-matched controls.

METHODS

Full retinal thicknesses of ten areas were assessed using spectral domain optical coherence tomography. Confounding variables, such as age, gender, and glycated haemoglobin (HbA1c) level, were assessed by regression analysis.

MAIN OUTCOME MEASURES

Mean retinal thickness of ten areas.

RESULTS

The mean thickness of the fovea was 215.8 ± 18.9 μm in the diabetes group and 222.0 ± 18.6 μm in the control group (p = 0.04). The mean thickness of the temporal parafovea was 319.9 ± 16.7 μm in the diabetes group and 326.0 ± 14.4 μm in the control group (p = 0.01). The mean thickness of the temporal perifovea was 276.4 ± 27.9 μm in the diabetes group and 284.8 ± 17.4 μm in the control group (p = 0.02). There were no significant differences in retinal thickness between groups in other areas (p > 0.05). Regression analysis revealed that decreased retinal thickness of the temporal perifovea was associated with a higher HbA1c level (>8.7%) (p = 0.04).

CONCLUSION AND RELEVANCE

Subtle structural changes in the retina may occur in diabetes without DR. Decreased retinal thickness appeared to begin in the fovea and temporal areas. A high HbA1c level was the main factor influencing retinal thickness.

Effect of age on the diagnostic efficiency of HbA1c for diabetes in a Chinese middle-aged and elderly population: The Shanghai Changfeng Study

Background and aims

Glycated hemoglobin A1c (HbA1c) ≥6.5% (or 48mmol/mol) has been recommended as a new diagnostic criterion for diabetes; however, limited literature is available regarding the effect of age on the HbA1c for diagnosing diabetes and the causes for this age effect remain unknown. In this study, we investigated whether and why age affects the diagnostic efficiency of HbA1c for diabetes in a community-based Chinese population.

Methods

In total, 4325 participants without previously known diabetes were enrolled in this study. Participants were stratified by age. Receiver operating characteristic curve (ROC) was plotted for each age group and the area under the curve (AUC) represented the diagnostic efficiency of HbA1c for diabetes defined by the plasma glucose criteria. The area under the ROC curve in each one-year age group was defined as AUCage. Multiple regression analyses were performed to identify factors inducing the association between age and AUCage based on the changes in the β and P values of age.

Results

The current threshold of HbA1c (≥6.5% or 48mmol/mol) showed low sensitivity (35.6%) and high specificity (98.9%) in diagnosing diabetes. ROC curve analyses showed that the diagnostic efficiency of HbA1c in the ≥75 years age group was significantly lower than that in the 45–54 years age group (AUC: 0.755 vs. 0.878; P<0.001). Pearson correlation analysis showed that the AUCage of HbA1c was negatively correlated with age (r = -0.557, P = 0.001). When adjusting the red blood cell (RBC) count in the multiple regression model, the negative association between age and AUCage disappeared, with the regression coefficient of age reversed to 0.001 and the P value increased to 0.856.

Conclusions

The diagnostic efficiency of HbA1c for diabetes decreased with aging, and this age effect was induced by the decreasing RBC count with age. HbA1c is unsuitable for diagnosing diabetes in elderly individuals because of their physiologically decreased RBC count.

Serum 1,5-anhydroglucitol level as a screening tool for diabetes mellitus in a community-based population at high risk of diabetes

AIMS

Early diagnosis of diabetes yields significant clinical benefits; however, currently available diagnostic tools for community-based population are limited. This study aimed to assess the value of serum 1,5-anhydroglucitol (1,5-AG) for the diagnosis and screening of diabetes mellitus in a community-based population at high risk of diabetes.

METHODS

In this diagnostic test, 1170 participants underwent a 75-g oral glucose tolerance test. Venous blood samples were collected for fasting blood glucose (FBG), 2-h postprandial blood glucose (PBG), and glycosylated hemoglobin A1c (HbA1c) measurements. Serum 1,5-AG levels were detected by the GlycoMark assay, and a receiver operating characteristic (ROC) curve was generated to assess their diagnostic value for diabetes.

RESULTS

A total of 298 adults were diagnosed with diabetes, indicating a prevalence of 25.47%. Partial Pearson correlation analysis adjusted for age and body mass index showed that serum 1,5-AG level was negatively correlated with FBG, PBG, and HbA1c (all P < 0.01). Areas under the curves (AUCs) for serum 1,5-AG, FBG, PBG, and HbA1c in identifying diabetes were 0.920, 0.874, 0.933, and 0.887, respectively. According to the ROC curve, the optimal cutoff value of serum 1,5-AG for diagnosing diabetes was 11.18 μg/ml, which yielded a sensitivity of 92.6% and a specificity of 82.3%, respectively. Comparisons between 1,5-AG and HbA1c showed that both the AUC and sensitivity of 1,5-AG were higher than those of HbA1c (both P < 0.01).

CONCLUSIONS

Serum 1,5-AG is a simple and effective marker with high sensitivity and specificity for identifying diabetes in populations at high risk of diabetes.

Long-term weight-change slope, weight fluctuation and risk of type 2 diabetes mellitus in middle-aged Japanese men and women: findings of Aichi Workers' Cohort Study

OBJECTIVE

This study aims to investigate the association of long-term weight-change slopes, weight fluctuation and the risk of type 2 diabetes mellitus (T2DM) in middle-aged Japanese men and women.

METHODS

A total of 4234 participants of Aichi Workers' Cohort Study who were aged 35-66 years and free of diabetes in 2002 were followed through 2014. Past body weights at the ages of 20, 25, 30, 40 years, and 5 years before baseline as well as measured body weight at baseline were regressed on the ages. Slope and root-mean-square-error of the regression line were obtained and used to represent the weight changes and the weight fluctuation, respectively. The associations of the weight-change slopes and the weight fluctuation with incident T2DM were estimated by Cox proportional hazards models.

RESULTS

During the median follow-up of 12.2 years, 400 incident cases of T2DM were documented. After adjustment for baseline overweight and other lifestyle covariates, the weight-change slopes were significantly associated with higher incidence of T2DM (hazard ratio (HR): 1.80, 95% confident interval (CI): 1.17-2.77 for men; and HR: 2.78, 95% CI: 1.07-7.23 for women), while the weight fluctuation was not (HR: 1.08, 95% CI: 1.00-1.18 for men and HR: 1.02, 95% CI: 0.84-1.25 for women).

CONCLUSIONS

Regardless of the presence of overweight, the long-term weight-change slopes were significantly associated with the increased risk of T2DM; however, the weight fluctuation was not associated with the risk of T2DM in middle-aged Japanese men and women.

Evaluation of a new hemoglobin A1c analyzer for point-of-care testing

BACKGROUND

There has been an increasing desire for the use of point-of-care testing (POCT) by both primary care clinicians and patients. This study aimed to evaluate the performance of a new POCT analyzer for hemoglobin A1c (HbA1c) testing.

METHODS

We assessed the accuracy, precision, and linearity of the POCT HbA1c analyzer (A1C EZ 2.0) with the Tosoh G8 Analyzer as comparative instrument, following the Clinical and Laboratory Standards Institute (CLSI) protocols. We evaluated sensitivity and specificity of the A1C EZ 2.0 in the clinical diagnosis of diabetes among 842 subjects from 79 communities in Beijing, China.

RESULTS

Using regression analysis, the slope of the A1C EZ 2.0 vs the Tosoh G8 Analyzer was 0.9938, with an intercept of 0.0964 and a concordance correlation coefficient of 0.978. For precision, the reproducibility of CV (CV_T ) were 3.7% and 2.7% at a lower (36 mmol/mol (5.4%)) and higher (107 mmol/mol (11.9%)) level of HbA1c respectively. The area under the receiver operating characteristic (ROC) curve for clinical diagnosis of diabetes was 0.911 with the HbA1c cut-off value of 44 mmol/mol (6.14%). At the HbA1c level of 48 mmol/mol (6.5%), the sensitivity and specificity were76.1% and 86.6%.

CONCLUSION

The A1C EZ 2.0 has a high accuracy and precision, with a wide range of linearity, compared to a comparative laboratory instrument. It met analytical quality specifications and could be suitable for the clinical management of diabetes mellitus.

Performance of Fasting Plasma Glucose and Postprandial Urine Glucose in Screening for Diabetes in Chinese High-risk Population

Background:

The conventional approaches to diabetes screening are potentially limited by poor compliance and laboratory demand. This study aimed to evaluate the performance of fasting plasma glucose (FPG) and postprandial urine glucose (PUG) in screening for diabetes in Chinese high-risk population.

Methods:

Nine hundred and nine subjects with high-risk factors of diabetes underwent oral glucose tolerance test after an overnight fast. FPG, hemoglobin A1c, 2-h plasma glucose (2 h-PG), and 2 h-PUG were evaluated. Diabetes and prediabetes were defined by the American Diabetes Association criteria. The area under the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy of 2 h-PUG, and the optimal cut-off determined to provide the largest Youden index. Spearman correlation was used for relationship analysis.

Results:

Among 909 subjects, 33.4% (304/909) of subjects had prediabetes, and 17.2% (156/909) had diabetes. The 2 h-PUG was positively related to FPG and 2 h-PG (r = 0.428 and 0.551, respectively, both P < 0.001). For estimation of 2 h-PG ≥ 7.8 mmol/L and 2 h-PG ≥ 11.1 mmol/L using 2 h-PUG, the area under the ROC curve were 0.772 (95% confidence interval [CI ]: 0.738–0.806) and 0.885 (95% CI: 0.850–0.921), respectively. The corresponding optimal cut-offs for 2 h-PUG were 5.6 mmol/L and 7.5 mmol/L, respectively. Compared with FPG alone, FPG combined with 2 h-PUG had a higher sensitivity for detecting glucose abnormalities (84.1% vs. 73.7%, P < 0.001) and diabetes (82.7% vs. 48.1%, P < 0.001).

Conclusion:

FPG combined with 2 h-PUG substantially improves the sensitivity in detecting prediabetes and diabetes relative to FPG alone, and may represent an efficient layperson-oriented diabetes screening method.

Cutoff Point of HbA1c for Diagnosis of Diabetes Mellitus in Chinese Individuals

Background

The purpose of the present study was to find the optimal threshold of glycated hemoglobin (HbA1c) for diagnosis of diabetes mellitus in Chinese individuals.

Methods

A total of 8 391 subjects (including 2 133 men and 6 258 women) aged 40–90 years with gradable retinal photographs were recruited. The relationship between HbA1c and diabetic retinopathy (DR) was examined. Receiver operating characteristic (ROC) curves were used to find the optimal threshold of HbA1c in screening DR and diagnosing diabetes.

Results

HbA1c values in patients with DR were significantly higher than in those with no DR. The ROC curve for HbA1c had an area under the curve of 0.881 (95%CI 0.857–0.905; P = 0.000). HbA1c at a cutoff of 6.5% had a high sensitivity (80.6%) and specificity (86.9%) for detecting DR.

Conclusions

HbA1c can be used to diagnose diabetes in a Chinese population, and the optimal HbA1c cutoff point for diagnosis is 6.5%.

Ideal glycated hemoglobin cut-off points for screening diabetes and prediabetes in a Chinese population

AIMS/INTRODUCTION

The aims of the present study were to evaluate the diagnostic value of fasting plasma glucose, 2-h postload plasma glucose and glycosylated hemoglobin (HbA1c) measurements in the screening of diabetes and prediabetes, and to determine the cut-off point of HbA1c in the diagnosis of diabetes and prediabetes in a Chinese population.

MATERIALS AND METHODS

A total of 7,611 individuals aged 40 years or older, who did not have a prior history of diabetes, were randomly selected in the Changchun area. For each participant, a questionnaire was completed, and a physical examination and an oral glucose tolerance test were carried out. The values of fasting plasma glucose, 2-h postload plasma glucose and HbA1c were compared by area under the receiver operating characteristic curves. The Youden index was used to identify the optimal cut-off point of HbA1c in the diagnosis of diabetes and prediabetes.

RESULTS

The prevalence of newly diagnosed diabetes and prediabetes was 12.71% and 29.39%, respectively. In participants with newly diagnosed diabetes, the area under the receiver operating characteristic curve was 0.8368 for fasting plasma glucose, 0.9330 for 2-h postload plasma glucose and 0.8064 for HbA1c; whereas for prediabetes, these values were 0.8022, 0.9288 and 0.6895, respectively. In addition, an HbA1c threshold of 6.3% showed the highest Youden index (0.4799) for detecting diabetes; furthermore, an HbA1c threshold of 5.8% showed the highest Youden index (0.2866) for detecting prediabetes.

CONCLUSIONS

HbA1c ≥6.3% (45 mmol/mol) and between 5.8% and 6.2% (40-44 mmol/mol) were the optimal cut-off values for the diagnosis of diabetes and prediabetes, respectively, in a Chinese population.

Plasma glucose and hemoglobin A1c for the detection of diabetes in Chinese adults

BACKGROUND

The aim of the present study was to evaluate the performance of plasma glucose (PG) and HbA1c for the detection of diabetes in the general population in China.

METHODS

A cross-sectional analysis was conducted in a nationally representative sample of 98,658 Chinese adults aged ≥18 years. Fasting plasma glucose and HbA1c levels were measured in all participants after at least a 10-h overnight fast. An oral glucose tolerance test (OGTT) was conducted among participants without a self-reported history of diagnosed diabetes.

RESULTS

An HbA1c ≥6.5% could identify 4.57% of Chinese adults as having newly detected diabetes, followed by fasting PG (FPG) and 2-h PG at 4.52% and 3.50%, respectively. Approximately 1.95% of the total population was detected by HbA1c but not by FPG or 2-h PG. However, FPG plus HbA1c could identify most (85.2%) diabetic individuals identified by any of the three tests (i.e., FPG, 2-h PG, and HbA1c). Levels of most cardiovascular risk factors, such as body mass index, waist circumference, and cholesterol, were higher in diabetes detected by HbA1c alone than in diabetes identified by the OGTT.

CONCLUSIONS

Although HbA1c ≥6.5% has been recommended by the American Diabetes Association as one of the diagnostic tests for diabetes, caution should be used to avoid potential overdiagnosis when interpreting diabetes identified by elevated HbA1c alone.

Rapid Elevation in CMPF May Act As a Tipping Point in Diabetes Development

Prediabetes, a state of mild glucose intolerance, can persist for years before a sudden decline in beta cell function and rapid deterioration to overt diabetes. The mechanism underlying this tipping point of beta cell dysfunction remains unknown. Here, the furan fatty acid metabolite CMPF was evaluated in a prospective cohort. Those who developed overt diabetes had a significant increase in CMPF over time, whereas prediabetics maintained chronically elevated levels, even up to 5 years before diagnosis. To evaluate the effect of increasing CMPF on diabetes progression, we used obese, insulin-resistant models of prediabetes. CMPF accelerated diabetes development by inducing metabolic remodeling, resulting in preferential utilization of fatty acids over glucose. This was associated with diminished glucose-stimulated insulin secretion, increased ROS formation, and accumulation of proinsulin, all characteristics of human diabetes. Thus, an increase in CMPF may represent the tipping point in diabetes development by accelerating beta cell dysfunction.

Standardising HbA1c-based diabetes diagnosis: opportunities and challenges

Globally, the incidence of diabetes mellitus is rising at an alarming rate and has become a health crisis that threatens the economies of all nations. Therefore, diagnosing diabetes has become an important issue in the management of diabetes. Glycated hemoglobin (HbA1c) is now recommended as a means to diagnose diabetes, but its use still has limitations. In this article, the biology, measurement, standardization, and opportunities and challenges of the use of HbA1c to diagnose diabetes are reviewed. More specifically, its use in China and the Asian region is discussed in detail.

Comparison of the Current Diagnostic Criterion of HbA1c with Fasting and 2-Hour Plasma Glucose Concentration

To determine the effectiveness of hemoglobin A1c (HbA1c) ≥ 6.5% in diagnosing diabetes compared to fasting plasma glucose (FPG) ≥ 126 mg/dL and 2-hour plasma glucose (2hPG) ≥ 200 mg/dL in a previously undiagnosed diabetic cohort, we included 5,764 adult subjects without established diabetes for whom HbA1c, FPG, 2hPG, and BMI measurements were collected. Compared to the FPG criterion, the sensitivity of HbA1c ≥ 6.5% was only 43.3% (106 subjects). Compared to the 2hPG criterion, the sensitivity of HbA1c ≥ 6.5% was only 28.1% (110 subjects). Patients who were diabetic using 2hPG criterion but had HbA1c < 6.5% were more likely to be older (64 ± 15 versus 60 ± 15 years old, P = 0.01, mean ± STD), female (53.2% versus 38.2%, P = 0.008), leaner (29.7 ± 6.1 versus 33.0 ± 6.6 kg/m(2), P = 0.000005), and less likely to be current smokers (18.1% versus 29.1%, P = 0.02) as compared to those with HbA1c ≥ 6.5%. The diagnostic agreement in the clinical setting revealed the current HbA1c ≥ 6.5% is less likely to detect diabetes than those defined by FPG and 2hPG. HbA1c ≥ 6.5% detects less than 50% of diabetic patients defined by FPG and less than 30% of diabetic patients defined by 2hPG. When the diagnosis of diabetes is in doubt by HbA1c, FPG and/or 2hPG should be obtained.

Can HbA1c replace OGTT for the diagnosis of diabetes mellitus among Chinese patients with impaired fasting glucose?

BACKGROUND

HbA1c ≥ 6.5% has been recommended as a diagnostic criterion for the detection of diabetes mellitus (DM) since 2010 because of its convenience, stability and significant correlation with diabetic complications. Nevertheless, the accuracy of HbA1c compared to glucose-based diagnostic criteria varies among subjects of different ethnicity and risk profile.

OBJECTIVES

This study aimed to evaluate the accuracy of HbA1c for diagnosing DM compared to the diagnosis by oral glucose tolerance test (OGTT) and the optimal HbA1c level to diagnose DM in primary care Chinese patients with impaired fasting glucose (IFG).

METHODS

A cross-sectional study was carried out in three public primary care clinics in Hong Kong. About 1128 Chinese adults with IFG (i.e. FG level between 5.6 and 6.9 mmol/l in the past 18 months) were recruited to receive paired OGTT and HbA1c tests. Sensitivities and specificities of HbA1c at different threshold levels for predicting DM compared to the diagnosis by OGTT were evaluated. A receiver operating characteristic (ROC) curve was used to determine the optimal cut-off level.

RESULTS

Among the 1128 subjects (mean age 64.2±8.9 year, 48.8% male), 229 (20.3%) were diagnosed to have DM by OGTT. The sensitivity and specificity of HbA1c ≥6.5% were 33.2% and 93.5%, respectively, for predicting DM diagnosed by OGTT. The area under the ROC curve was 0.770, indicating HbA1c had fair discriminatory power. The optimal cut-off threshold of HbA1c was 6.3% for discriminating DM from non-DM, with sensitivity and specificity of 56.3% and 85.5%, respectively. HbA1c ≥ 5.6% has the highest sensitivity and negative predictive value of 96.1% and 94.5%, respectively.

CONCLUSIONS

HbA1c ≥ 6.5% is highly specific in identifying people with DM, but it may miss the majority (66.8%) of the DM cases. An HbA1c threshold of <5.6% is more appropriate to be used for the exclusion of DM. OGTT should be performed for the confirmation of DM among Chinese patients with IFG who have an HbA1c between 5.6% and 6.4%.