HbA1c Cut-off Point Research Articles

Selection of clinical diagnosic cut point of HbA1C in Chongming rural areas of Shanghai

Objective To investigate the optimal HbA1C threshold to be used for the diagnosis of diabetes mellitus in Chongming rural area, and further to evaluate the optimal HbA1C cutoff values in different age stratifications and body mass index classifications. Methods Data from 9, 981 individuals aged greater than 40 years who participated in a population-based cross-sectional survey in Shanghai, China, were analyzed. A 2 h 75 g oral glucose tolerance test(OGTT)value was used to diagnose diabetes. The performance of HbA1C was evaluated against the results of the OGTTs by using receiver operating characteristic(ROC)curve analysis. Results At the optimal HbA1C cutoff point of 6.15% for newly diagnosed diabetes, sensitivity was 69.73%, and specificity was 89.71%. The optimal HbA1C cutoff points for diabetes were 6.05% in subject with age less than 60 years(sensitivity was 72.88%, and specificity was 90.25%), and 6.25% in subjects with age≥60 years(sensitivity was 70.89%, and specificity was 92.34%). The optimal HbA1C cutoff points for diabetes were 6.05% in normal-weight(with sensitivity 70.94%, and specificity 89.93%), 6.25% in overweight(with sensitivity 70.21%, and specificity 90.32%), and 6.35% in obese population(with sensitivity 72.33%, and specificity 92.75%). Conclusion An HbA1C threshold of 6.15% was highly specific for detecting undiagnosed diabetes. The HbA1C diagnosis cutoff point can be affected by age and overweight/obesity status. (Chin J Endocrinol Metab, 2018, 34: 223-227) Key words: Diabetes mellitus; HbA1C; Obesity; Age

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.

HbA1c Cutoff for Prediabetes and Diabetes Based on Oral Glucose Tolerance Test in Obese Children and Adolescents.

BackgroundOral glucose tolerance test (OGTT) is a traditional diagnostic tool for diabetes. Hemoglobin A1c (HbA1c) is an alternative method used in adults; however, its application in youths has been controversial. We evaluated the diagnostic performance of HbA1c and determined optimal cutoff points for detecting prediabetes and diabetes in youth.MethodsThis retrospective study included 389 obese children (217 boys, 55.8%) who had undergone simultaneous OGTT and HbA1c testing at six hospitals, Korea, between 2010 and 2016. Subjects were diagnosed with diabetes (fasting glucose ≥ 7.0 mmol/L; 2-hour glucose ≥ 11.1 mmol/L) or prediabetes (fasting glucose 5.6–6.9 mmol/L; 2-hour glucose 7.8–11.0 mmol/L). The diagnostic performance of HbA1c for prediabetes and diabetes was determined using the area under the receiver operating characteristic curve (AUC).ResultsAt diagnosis, 197 (50.6%) subjects had normoglycemia, 121 (31.1%) had prediabetes, and 71 (18.3%) had diabetes. The kappa coefficient for agreement between OGTT and HbA1c was 0.464. The optimal HbA1c cutoff points were 5.8% (AUC, 0.795; a sensitivity of 64.1% and a specificity of 83.8%) for prediabetes and 6.2% (AUC, 0.972; a sensitivity of 91.5% and a specificity of 93.7%) for diabetes. When HbA1c (≥ 6.2%) and 2-hour glucose level were used to diagnose diabetes, 100% were detected.ConclusionPediatric criteria for HbA1c remain unclear, therefore, we recommend the combination of fasting and 2-hour glucose levels, in addition to HbA1c, in the diagnosis of childhood prediabetes and diabetes.

Impaired β-cell function and decreased insulin sensitivity in subjects with normal oral glucose tolerance but isolated high glycosylated hemoglobin.

The pathophysiology is distinct in various state of glucose metabolism abnormalities. As the defect of individuals with normal oral glucose tolerance (NGT) but isolated high glycosylated hemoglobin (HbA1c), i.e. iHH, was ambiguous, we aimed to investigate the insulin sensitivity and β-cell function of iHH. According to the ADA criteria of HbA1c cut-off point (5.7%), 3,517 subjects with NGT screened from a total of 7,855 middle-aged and elderly Chinese without known diabetes were divided into two groups, 1,877 subjects with HbA1c < 5.7% and 1,640 with HbA1c ≥ 5.7% (i.e. iHH). A variety of indexes from blood glucose and insulin levels of oral glucose tolerance were calculated to evaluate insulin sensitivity and β-cell function. Compared with subjects with HbA1c < 5.7%, individuals with iHH had increased homeostasis model assessment of insulin resistance (HOMA-IR), early-phase and total insulin release indexes (insulin release index 30 min and 120 min, i.e. INRS30 and INSR120), and decreased Matsuda insulin sensitivity index (Matsuda ISI) and early-phase disposition index (DI30). After adjustment for confounding factors, the significant difference of HOMA-IR and INSR30 between the two groups vanished, however, Matsuda ISI and DI30 remained significantly lower and INSR120 was still higher in iHH group compared with HbA1c < 5.7%. In conculsion, subjects with NGT may not be perfectly healthy in glycometabolism, those with iHH have impaired early-phase β-cell function and decreased insulin sensitivity.

Application of HbA1C for diagnosing diabetes in Harbin

Objective To evaluate the sensitivity and specificity of different HbA1C cutoff points for diabetes diagnosis in high risk outpatients in Harbin. Methods A total of 2 122 high risk outpatients(male 1 032 and female 1 090)for diabetes screening in the Fourth affiliated Hospital of Harbin Medical University from April 2013 to February 2015 were included in this study, with the average age of(49.26±13.00)year. Oral glucose tolerance tests(OGTT)were conducted and HbA1C levels were examined in these patients. The sensitivity and specificity of different HbA1C cutoff points were calculated and a receiver operator characteristic(ROC)curve was then built. Results The average level of HbA1C in these subjects was(6.45±1.72)%. The prevalence of diabetes was 41.85%. The area under ROC curve(AUC)was 0.89 with the optimal cutoff point of HbA1C 6.0% and 0.68 for the highest Yonden index. The sensitivity and specificity of HbA1C 6.0% were 84.01% and 83.67% respectively. The sensitivity and specificity of HbA1C 6.5% were 62.84% and 95.92%, respectively. The AUC of HbA1C≥6.5% was 0.732. Conclusion HbA1C works well as the diagnostic standard for diabetes in high risk outpatients of Harbin city. The cutoff point of HbA1C 6.0% is suitable for screening diabetes in high risk population, and HbA1C 6.5% is appropriate for diabetes diagnosis, with high sensitivity and specificity. (Chin J Endocrinol Metab, 2017, 33: 562-566) Key words: HbA1C; Diabetes; Diagnosing; Cutoff point

Associations of mid-pregnancy HbA1c with gestational diabetes and risk of adverse pregnancy outcomes in high-risk Taiwanese women.

BackgroundThe objective of this study was to investigate the associations among the mid-pregnancy glycated hemoglobin A1c (HbA1c) level, gestational diabetes (GDM), and risk of adverse pregnancy outcomes in women without overt diabetes and with positive 50-g, 1-h glucose challenge test (GCT) results (140 mg/dL or greater).MethodsThis prospective study enrolled 1,989 pregnant Taiwanese women. A two-step approach, including a 50-g, 1-h GCT and 100-g, 3-h oral glucose tolerance test (OGTT), was employed for the diagnosis of GDM at weeks 23–32. The mid-pregnancy HbA1c level was measured at the time the OGTT was performed. A receiver operating characteristic (ROC) curve was used to determine the relationship between the mid-pregnancy HbA1c level and GDM. Multiple logistic regression models were implemented to assess the relationships between the mid-pregnancy HbA1c level and adverse pregnancy outcomes.ResultsAn ROC curve demonstrated that the optimal mid-pregnancy HbA1c cut-off point to predict GDM, as diagnosed by the Carpenter-Coustan criteria using a two-step approach, was 5.7%. The area under the ROC curve of the mid-pregnancy HbA1c level for GDM was 0.70. Compared with the levels of 4.5–4.9%, higher mid-pregnancy HbA1c levels (5.0–5.4, 5.5–5.9, 6.0–6.4, 6.5–6.9, and >7.0%) were significantly associated with increased risks of gestational hypertension or preeclampsia, preterm delivery, admission to the neonatal intensive care unit, low birth weight, and macrosomia (the odds ratio [OR] ranges were 1.20–9.98, 1.31–5.16, 0.88–3.15, 0.89–4.10, and 2.22–27.86, respectively).ConclusionsThe mid-pregnancy HbA1c level was associated with various adverse pregnancy outcomes in high-risk Taiwanese women. However, it lacked adequate sensitivity and specificity to replace the two-step approach in the diagnosis of GDM. The current study comprised a single-center prospective study; thus, additional, randomized control design studies are required.

Hemoglobin A1c and risk of left atrial thrombus and spontaneous echo contrast in non-valvular atrial fibrillation patients

ObjectivesTo evaluate the relationship between hemoglobin A1c (HbA1c) and risk of left atrial thrombus/spontaneous echo contrast (LAT/SEC) in non-valvular atrial fibrillation (AF) patients.MethodsIn this retrospective study, 1158 consecutive non-valvular AF patients undergoing transesophageal echocardiography prior to radiofrequency catheter ablation or electric cardioversion were enrolled. Baseline characteristics were collected and analyzed.ResultsThere were 87 (7.5%) patients with LAT/SEC. The HbA1c levels in the patients with LAT/SEC were significantly higher than that in patients without LAT/SEC (6.13 ± 0.41 vs. 5.89 ± 0.45 μmol/L, P < 0.001). The optimal cut-off point for HbA1c predicting LAT/SEC was 6.1% determined by receiver-operating characteristic curve. The area under the curve is 0.788 (95% confidence interval: 0.764–0.812). HbA1c ≥6.1% was an independent risk factor for LAT/SEC (odds ratio, 1.74; 95% confidence interval, 1.01–2.98; P = 0.045).ConclusionsElevated HbA1c indicated a significantly increased risk for LAT/SEC in non-valvular AF patients. HbA1c might have significance in predicting the risk for prothrombotic state in non-valvular AF patients.

Diagnostic accuracy of glycated hemoglobin for post-transplantation diabetes mellitus after kidney transplantation: systematic review and meta-analysis

Early detection of post-transplantation diabetes mellitus (PTDM) allows prompt clinical and pharmacological interventions, reducing the chance of adverse outcomes. We conducted a systematic review and meta-analysis to determine the overall diagnostic accuracy of glycated hemoglobin (HbA1c) for the diagnosis of renal PTDM. We searched MEDLINE, Embase and SCOPUS up to June 2016. Studies that included adults without previous diabetes were selected if they reported an oral glucose tolerance test as a reference test, HbA1c levels measured by standardized methods and data necessary for drawing 2 × 2 tables. A bivariate model was used to calculate the pooled estimates. Based on 2057 kidney recipients from six studies, an HbA1c cut-off point of 6.5% in early months after transplant resulted in sensitivity of 0.48 [95% confidence interval (95% CI) 0.31-0.65], specificity of 0.96 (95% CI 0.95-0.97), positive likelihood ratio (PLR) of 12.0 (95% CI 7.4-19.5) and negative likelihood ratio (NLR) of 0.54 (95% CI 0.38-0.77). Based on 1888 kidney recipients from four studies, an HbA1c cut-off point of 6.2% early after transplant resulted in sensitivity of 0.76 (95% CI 0.49-0.91), specificity of 0.89 (95% CI 0.86-0.92), PLR of 7.18 (95% CI 5.29-9.75) and NLR of 0.27 (95% CI 0.11-0.65). HbA1c cut-off points of 6.5% and 6.2% presented high specificity but low/moderate sensitivity to diagnose PTDM.

The clinical value of HbA1c in combination with FPG in the early screening of the elderly with type 2 diabetes

Objective: To investigate the FPG associated with HbA1c diagnosis of T2DM, to clear the best point of tangency HbA1c diagnosis of T2DM. Methods: Using simple random sampling method, from this group of T2DM field epidemiological investigation data in the database we randomly selected 300 cases of T2DM patients, 300 cases of healthy people. The sensitivity and specificity of FPG, HbA1c and HbA1c/FPG combination were calculated by diagnostic screening test; Using ROC curve evaluation FPG, HbA1c and HbA1c in combination with FPG diagnosis value of T2DM. Results: The cutoff point of FPG for diagnosing T2DM was 6.19 mmol/L, the sensitivity and specificity were respectively: 83.00%, 93.67%, area under the curve (AUC) was 0.928; the cutoff point of HbA1c for diagnosing T2DM was 6.40%, the sensitivity and specificity were respectively: 87.00%, 90.33%, area under the curve (AUC) is 0.935;Combined use of HbA1c and FPG in the diagnosis of T2DM, simultaneous detection of HbA1c and FPG, when HbA1c≥ 6.40% or FPG≥6.19 mmol/L diagnosed with T2DM, the sensitivity and specificity were respectively: 97.79%, 84.61%, area under the curve (AUC) is 0.960. Conclusions: The cutoff point of HbA1c for diagnosing T2DM was 6.40% , Combined HbA1c and FPG in the T2DM diagnosis, which can greatly improve the sensitivity, the combined application is more conducive to the early screening of T2DM.

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

BackgroundThe purpose of the present study was to find the optimal threshold of glycated hemoglobin (HbA1c) for diagnosis of diabetes mellitus in Chinese individuals.MethodsA 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.ResultsHbA1c 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.ConclusionsHbA1c can be used to diagnose diabetes in a Chinese population, and the optimal HbA1c cutoff point for diagnosis is 6.5%.

Use of HbA1c to diagnose type 2 diabetes mellitus among high risk Sri Lankan adults

AimEven though, glycosylated hemoglobin (HbA1c) was found to be effective in predicting diabetes especially in Caucasians there is limited evidence of its diagnostic utility in high risk Sri Lankan adults. This study aimed to determine the optimal HbA1c cut-off points for detecting diabetes in a high risk population in Sri Lanka. Materials and methodsThis community based study consisted of 254 previously healthy adults with history of diabetes in one or more first-degree relatives. Fasting plasma glucose (FPG) , glucose tolerance test (GTT) and HbA1c were measured in all and GTT was used as a reference to diagnose diabetes. Receiver operating characteristic curve was created to find the optimum HbA1c cut-off value to predict diabetes. ResultsPrevalence of diabetes was 12.2% (n=31) with FPG and 16.1% (n=41) with GTT. Prevalence rose to 27.6% (P<0.01) when HbA1c with cut-off of ≥6.5% was used as the diagnostic test. The ROC curves showed the HbA1c threshold of 6.3% provided the optimum balance between sensitivity (80.5%) and specificity (79%). In compared to GTT, FPG had only a modest sensitivity (65%) in diagnosing diabetes in this high risk population. ConclusionOur study showed that optimum HbA1C cut-off for detecting diabetes was 6.3% and it had better sensitivity, but lower specificity than FPG. This study further showed that the prevalence of diabetes would become double if HbA1c is used over FPG to screen this high risk population.

Diagnostic performance of glycated hemoglobin for diabetic retinopathy in non-diabetic older overweight/obese African-Americans

ObjectivesAlthough clinicians do not routinely screen for diabetic retinopathy in non-diabetic patients, previous studies have shown that diabetic retinopathy can occur in patients with prediabetes. However, due to the limitations of glycated hemoglobin (HbA1c) in overweight/obese subjects, African-Americans and older adults, little is known about the correlation between HbA1c and diabetic retinopathy in non-diabetic older overweight/obese African-Americans. The aims of this study were to determine the association between HbA1c and diabetic retinopathy, and the optimal diagnostic threshold of HbA1c that predicts diabetic retinopathy in non-diabetic older overweight/obese African-Americans. MethodsThe 2005–2012 data from the U.S. National Health and Nutrition Examination Surveys (NHANES) were utilized for this study. Prevalence odds ratios from logistic regression analyses were used to estimate risks of diabetic retinopathy across HbA1c categories, adjusting for age, sex, and hypertension. Receiver operating characteristic curve was used to determine diagnostic cutoff point of HbA1c for prevalent diabetic retinopathy. ResultsThere were gradients of increasing prevalence and odds of diabetic retinopathy with increasing HbA1c in non-diabetic overweight/obese African-Americans 50years of age and older. HbA1c cut-off point of 5.2% (AUC=.726, 95% CI=0.696–0.756) was found to maximize sensitivity [93.5%; 95% CI: 83.2–95.7] for diabetic retinopathy, though specificity [22.1%; 95% CI 19.9–32.8] was low. ConclusionCurrent criteria for diagnosis of prediabetes are effective in identifying many older overweight/obese African Americans with diabetic retinopathy. Based on our analysis, a lower HbA1c of 5.2% could serve as a more sensitive cutoff point for defining prediabetes in this population subgroup.

Glycosylated Hemoglobin Threshold for Predicting Diabetes and Prediabetes from the Fifth Korea National Health and Nutrition Examination Survey.

We aimed to estimate the threshold level of glycosylated hemoglobin (HbA1c) for the fasting plasma glucose of 100 and 126 mg/dL in the Korean adult population, using the 2011 Korea National Health and Nutrition Examination Survey. A total of 4,481 participants over 19 years of age without diabetic medications and conditions to influence the interpretation of HbA1c levels, such as anemia, renal insufficiency, liver cirrhosis, and cancers, were analyzed. A point-wise area under the receiver operating characteristic curve was used to estimate the optimal HbA1c cutoff value. A HbA1c threshold of 6.35% was optimal for predicting diabetes with a sensitivity of 86.9% and a specificity of 99.1%. Furthermore, the threshold of HbA1c was 5.65% for prediabetes, with a sensitivity of 69.3% and a specificity of 71%. Further prospective studies are needed to evaluate the HbA1c cutoff point for diagnosing prediabetes and diabetes in the Korean population.

A study on assessment of HbA1c level as a diagnostic criterion of type 2 diabetes mellitus

Aims and Objectives: We compared performance of HbA1c in diagnosis of type 2 diabetes mellitus with that of fasting plasma glucose and tried to determine cut off point of HbA1c for optimum sensitivity and specificity in a population of eastern India both from urban and rural background.Materials and Methods: The analysis was conducted in persons aged between 40 and 80 years, visiting our institution, who are newly diagnosed as diabetic and non-diabetic attending hospital for some other reason, who underwent FPG and HbA1c testing, in the time period January 2013 to August 2014.Results: From 100 individuals (mean age 54.6 years) HbA1c ? 6.5% produced sensitivity of 90% and specificity of 72%, positive predictive value 76.27% and negative predictive value 87.80% when compared to FPG ? 126 mg% as standard. By ROC curve, optimum cut off point for HbA1c was found to be 7.05% for diagnosis of diabetes.Conclusion: Using a cut off value of HbA1c of 7% may optimise detection of diabetes mellitus and ensure proper patient care.Asian Journal of Medical Sciences Vol.7(1) 2015 49-52

HbA1c Test as a Tool in the Diagnosis of Gestational Diabetes Mellitus.

AimsGestational diabetes mellitus (GDM) is a prevalent and potentially serious condition which may put both mothers and neonates at risk. The current recommendation for diagnosis is the oral glucose tolerance test (OGTT). This study aimed to determine the usefulness of HbA1c test as a diagnostic tool for GDM as compared to the traditional criteria based on the OGTT.MethodsThis was a diagnostic test accuracy study. We performed OGTT and HbA1c test in women attending prenatal visits at a tertiary hospital. GDM was defined according to WHO1999 or ADA/WHO 2013 criteria. ROC curve was used to evaluate the diagnostic performance of HbA1c. Sensitivity, specificity and likelihood ratios for different HbA1c cut-off points were calculated.ResultsOf the 262 women in the third trimester of gestation enrolled in the study, 86 (33%) were diagnosed with GDM. Only five of these women presented HbA1c ≥48 mmol/mol (6.5%). This cut-off point presented 100% specificity but very low sensitivity (7%). Based on ROC curve, and considering OGTT as the reference criterion, HbA1c ≥40 mmol/mol (5.8%) showed adequate specificity in diagnosing GDM (94.9%) but low sensitivity (26.4%). Unlike, HbA1c values of 31 mmol/mol (5.0%) presented adequate sensitivity (89.7%) but low specificity (32.6%) to detect GDM. For women with HbA1c ≥40 mmol/mol (5.8%), the positive and negative likelihood ratios were 5.14 (95%CI 2.49–10.63) and 0.78 (0.68–0.88), respectively. The post-test probability of GDM was about 40%, representing a 4.0-fold increase in the mean pre-test probability. This cut-off point could eliminate the need for the unpleasant and laborious OGTT tests in almost one third of cases, as 38% of patients with GDM may be diagnosable by HbA1c test alone.ConclusionsOur results show that combined HbA1c and OGTT measurements may be useful in diagnosing GDM.

Comparison of HbA1c and FPG as a screening tool for diagnosis of pre-diabetes and diabetes in Indian population

The aim of this study is to compare hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) tests as a mass screening tool for pre-diabetes and diabetes as defined by standard oral glucose tolerance test (OGTT). The study was community-based cross-sectional and carried out in urban field practice area of the Department of Community Medicine at Rohtak. A day before the study, subjects were advised to observe overnight fasting (at least 8 h) and were called at the nearest health center in the morning. Initial evaluation included detailed history and clinical examination to exclude any systemic diseases. FPG and 2-h plasma glucose after 75 g OGTT was used to diagnose pre-diabetes and diabetes in 1008 participant. Fasting plasma glucose and 2-h post glucose load were estimated by glucose oxidase method. HbA1c was measured using Cone lab 30i autoanlyser based on latex agglutination inhibition assay (EIA). The American Diabetic Association (ADA) criteria were used to categorize the subjects into pre-diabetes and diabetes (American Diabetes Association. Diabetes Care; 33 Suppl 1:S62–9, 2010). Performance of HbA1c and FPG was evaluated against the results of OGTT by receiver operating characteristics (ROC) curve analysis. The prevalence of pre-diabetes and newly diagnosed diabetes was found 20.6 and 12.5 %, respectively. For pre-diabetes, the area under the ROC curve was 0.831 for HbA1c and 0.807 for FPG (p value 0.205), whereas for diabetes, these values were 0.957 for HbA1c and 0.942 for FPG (p value 0.11). At the optimal HbA1c cutoff points of 5.4 % for pre-diabetes and of 6.2 % for newly diagnosed diabetes, sensitivities and specificities were 79.02, 79.31 and 94.24, 90.52 %, respectively. Similarly, FPG optimal cutoff points of ≥97 mg/dl for pre-diabetes and ≥119 mg/dl for diabetes were found to have maximum sensitivities (specificities) of 93.13 (63.32) and 93.53 (89.64), respectively. It is observed that at optimal cutoff of FPG ≥97 mg/dl and HbA1c ≥5.4 % for pre-diabetes and ≥119 mg/dl and 6.2 % for newly diagnosed diabetes, more true-positive cases are identified as compared to currently recommended ADA criteria when both were compared with results of 75 g OGTT. As a screening tool for newly diagnosed pre-diabetes and diabetes, the HbA1c measurement did not perform inferior than FPG. In this study population, FPG and HbA1c values lower than the currently recommended values of ADA were found to be better predictor of pre-diabetes and diabetes.

Increased hemoglobin A1c threshold for prediabetes remarkably improving the agreement between A1c and oral glucose tolerance test criteria in obese population.

It is unclear why the prevalence of diabetes and prediabetes, especially prediabetes, between diagnosed by oral glucose tolerance test (OGTT) and hemoglobin A1c (HbA1c) criteria, is substantially discordant. We aimed to evaluate the effects of obesity on the agreement between HbA1c and OGTT for diagnosing diabetes and prediabetes and identify the optimal HbA1c cutoff values in different body mass index (BMI) classifications. In a population-based, cross-sectional study in Harbin, China, 4325 individuals aged 20-74 years without a prior diagnosed diabetes were involved in this study. measure The performance and optimal cutoff points of HbA1c were assessed by receiver-operating characteristic curve. The contribution of BMI to HbA1c was analyzed by structural equational model. The agreement between HbA1c criteria and OGTT decreased with BMI gain (κ = 0.359, 0.312, and 0.275 in a normal weight, overweight, and obese population, respectively). The structural equational model results showed that BMI was significantly associated with HbA1c in normal glucose tolerance and prediabetes subjects but not in diabetes subjects. At a specificity of 80% for prediabetes and 97.5% for diabetes, the optimal HbA1c cutoff points for prediabetes and diabetes were 5.6% and 6.4% in normal-weight, 5.7% and 6.5% in overweight, and 6.0% and 6.5% in an obese population. When the new HbA1c cutoff values were used, the agreement in obese subjects increased almost to the level in normal-weight subjects. The poor agreement between HbA1c and OGTT criteria in an obese population can be significantly improved through increasing the HbA1c threshold for prediabetes.

Association between Glycosylated Haemoglobin Level and Contrast-Induced Acute Kidney Injury in Patients with Type 2 Diabetes Mellitus

Background: There are several reports suggesting that admission hyperglycaemia increases the risk of contrast-induced acute kidney injury (CI-AKI). However, it is not clear whether there has been an association between long-standing poor glycaemic control and the incidence of CI-AKI. The purpose of this study was to examine the impact of poor glycaemic control or elevated glycosylated haemoglobin (HbA1c) on the incidence of CI-AKI in patients with type 2 diabetes mellitus (T2DM). Methods: The present study prospectively enrolled 133 patients with T2DM undergoing elective coronary angiography (CAG) and/or intervention. All patients had an estimated glomerular filtration rate (eGFR) of ≥60 ml/min/1.73 m². Patients were divided into two groups: those with an optimal HbA1c (<7%) and those with an elevated HbA1c (≥7%). All had similar baseline characteristics and were hydrated appropriately. The outcome was assessed by the incidence of CI-AKI. Results: CI-AKI occurred in 2 of 41 patients (4.9%) with optimal HbA1c levels and 5 of 92 patients (5.4%) with elevated HbA1c levels (p = 0.89). The cutoff point of HbA1c was set at 6.5%, but no statistically significant difference between the two groups was observed [1 of 24 patients (4.1%) vs. 6 of 109 patients (5.5%), p = 0.79]. However, despite a high variability in the incidence of CI-AKI, there was no statistically significant difference between the two groups when varying CI-AKI definitions were considered. Conclusion: An elevated HbA1c level is not associated with a higher incidence of CI-AKI compared to optimal HbA1c levels in patients with T2DM (patients with an eGFR of ≥60 ml/min/1.73 m²) undergoing CAG and/or intervention.

Impact of HbA1c criterion on the definition of glycemic component of the metabolic syndrome: the China health and nutrition survey 2009.

BackgroundIn 2009, a unified definition of metabolic syndrome (MetS) was proposed, of which, the glycemic component is defined on the basis of fasting plasma glucose (FPG) level. Recently, the American Diabetes Association (ADA) recommended the use of glycated hemoglobin (HbA1c) as an alternative to FPG to define prediabetes. Hence, we aim to compare the performance of HbA1c and FPG in the definition of glycemic component of the MetS among Chinese adults.MethodsWe conducted a cross-sectional analysis of 7641 Chinese participants aged ≥18 years using data from the China Health and Nutrition Survey 2009. MetS was defined according to the consensus criteria in 2009. We compared the use of HbA1c versus FPG in the definition of the glycemic component of MetS. Increased HbA1c value was defined following the criterion of HbA1c cut-off point of ≥5.7% recommended by the ADA.ResultsOverall, 1136 (14.9%) had MetS according to FPG ≥ 5.6 mmol/l, and 1640 (21.5%) had MetS according to HbA1c ≥ 5.7%. Compared with individuals with FPG-based diagnosis of MetS, individuals with HbA1c-based diagnosis of MetS were older, had higher levels of LDL-C, magnesium, and transferrin, and lower levels of uric acid. Of those found to have MetS according to either FPG or HbA1c (n = 2008), overlap between HbA1c- and FPG-based diagnosis of MetS was limited (n = 768, 38.2%). The overlap index regarding MetS diagnosed by FPG or HbA1c persisted low in each evaluated subgroup (≤ 50.0%).ConclusionsWe note limited overlap and poor agreement between FPG- and HbA1c-based diagnosis of MetS. Screening MetS through introduction of HbA1c in addition to FPG could contribute to identification of more people with MetS.

Evaluation of performance of A1c and FPG tests for screening newly diagnosed diabetes defined by an OGTT among tuberculosis patients—A study from India

AimThe methods used for diagnosis of diabetes have limitations particularly in situations associated with stress hyperglycemia. Aim of this study was to evaluate the performance of A1c and fasting plasma glucose (FPG) tests for screening newly diagnosed diabetes (NDD) defined by OGTT among tuberculosis (TB) cases in India. MethodsA total of 983 subjects aged ≥18 years with TB were selected from 7 TB units – 4 urban, 2 rural and 1 semi-urban areas of Tamil Nadu, India, during August 2010–March 2011. Screening for diabetes was carried out by 2-h 75g OGTT. Classification of glucose intolerance status was based on WHO criteria. HbA1c was measured by high performance liquid chromatography using Bio-Rad turbo machine. HbA1c≥47.5mmol/mol was used for diagnosis of diabetes. FPG was estimated by glucose-oxidase method. Known cases of subjects with diabetes were excluded and final analysis was done using data of 779 individuals. The performance of A1c and FPG tests was evaluated against the results of OGTT using receiver operating characteristic curve analysis. ResultsPrevalence of NDD was 10.8%. The areas under the curve (AUC) were 0.754 [95% confidence interval (CI) 0.68–0.83] (p<0.001) for A1c and 0.662 (95% CI 0.58–0.74) for FPG (p<0.001) in NDD subjects. The HbA1c cut-off point of ≥47.5mmol/mol gave a sensitivity of 59.1% and specificity of 91.7%, and the respective values were 34.8% and 97.5% for FPG in subjects with NDD. ConclusionHbA1c performed better than FPG as a screening tool for newly diagnosed diabetes among subjects with TB.