Oral Glucose Tolerance Test Criteria Research Articles

How Can We Adopt the Glucose Tolerance Test to Facilitate Predicting Pregnancy Outcome in Gestational Diabetes Mellitus?

BackgroundWe investigated how 100-g oral glucose tolerance test (OGTT) results can be used to predict adverse pregnancy outcomes in gestational diabetes mellitus (GDM) patients.MethodsWe analyzed 1,059 pregnant women who completed the 100-g OGTT between 24 and 28 weeks of gestation. We compared the risk of adverse pregnancy outcomes according to OGTT patterns by latent profile analysis (LPA), numbers to meet the OGTT criteria, and area under the curve (AUC) of the OGTT graph. Adverse pregnancy outcomes were defined as a composite of preterm birth, macrosomia, large for gestational age, low APGAR score at 1 minute, and pregnancy-induced hypertension.ResultsOverall, 257 participants were diagnosed with GDM, with a median age of 34 years. An LPA led to three different clusters of OGTT patterns; however, there were no significant associations between the clusters and adverse pregnancy outcomes after adjusting for confounders. Notwithstanding, the risk of adverse pregnancy outcome increased with an increase in number to meet the OGTT criteria (P for trend=0.011); odds ratios in a full adjustment model were 1.27 (95% confidence interval [CI], 0.72 to 2.23), 2.16 (95% CI, 1.21 to 3.85), and 2.32 (95% CI, 0.66 to 8.15) in those meeting the 2, 3, and 4 criteria, respectively. The AUCs of the OGTT curves also distinguished the patients at risk of adverse pregnancy outcomes; the larger the AUC, the higher the risk (P for trend=0.007).ConclusionThe total number of abnormal values and calculated AUCs for the 100-g OGTT may facilitate tailored management of patients with GDM by predicting adverse pregnancy outcomes.

The impact of ferritin on the disassociation of HbA1c and mean plasma glucose.

To explore the impact of ferritin level on the disassociation of glycated hemoglobin A1c (HbA1c) and mean plasma glucose (MPG). We used a 2012-2013 cross-sectional survey conducted in Pinggu district, Beijing including 3095 Chinese participants aged 25-75 years. We categorized their glycemic status by interviewing for diagnosed diabetes and by measuring HbA1c, fasting plasma glucose (FPG), and 2-hours post-load plasma glucose (2-hours PPG). We fitted a multivariable regression model to explore the impact of ferritin on the association of HbA1c or glycated albumin (GA) and mean plasma glucose. A total of 5.65% of participants were diagnosed as diabetes using HbA1c criteria, and 9.79% using oral glucose tolerance test criteria. Compared with males, females had significantly lower hemoglobin levels (159.82 ± 11.56 vs 135.93 ± 12.62) and lower ferritin levels (113.00 [68.55, 185.50] vs 33.40 [12.40, 70.13]). Linear regression analysis performed in different groups classified by different diagnose criterion indicated that the correlation between MPG and HbA1c differs in different tertiles of ferritin (lowest vs middle vs highest: R2 = 0.507 vs 0.645 vs 0.687 in female; R2 = 0.415 vs 0.715 vs 0.615 in male), and the association between MPG and HbA1c diminished in the lowest tertile of ferritin. Ferritin level might affect the association between glucose and HbA1c, which should be taken into account when using HbA1c as a diagnosis criterion for diabetes and prediabetes.

Plasma glycated CD59 (gCD59), a novel biomarker for the diagnosis, management and follow up of women with Gestational Diabetes (GDM) \u2013 protocol for prospective cohort study

BackgroundThe prevalence of Gestational Diabetes (GDM) is rising and with it the number of mothers and children at risk of adverse outcomes. As treatment has been shown to reduce adverse events, it is imperative that we identify all at-risk pregnant women. In Ireland, the national standard of care is selective screening with a 2-hour 75 g oral glucose tolerance test (OGTT). Aiming for universal screening is of utmost importance but this is difficult given the length, the unfeasibility and impracticability of the OGTT. We aim to assess if the novel biomarker glycated CD59 (gCD59) is a suitable contender for the OGTT in identifying women with GDM.MethodsIn this prospective cohort study, the study participants will be consecutive pregnant women at Galway University Hospital, Galway, Ireland. Samples for the plasma gCD59 biomarker will be taken together with routine bloods at the first antenatal visit, at weeks 24–28 at the time of routine 75 g OGTT, in trimester 3- and 12-weeks post-partum for women with GDM while having their routine post-partum 75 g OGTT. The constructed database will contain baseline information on each study participant, baseline laboratory data, follow-up laboratory data and pregnancy related outcomes. We aim to recruit a total of 2,000 participants over the project period and with a national GDM prevalence of 12–13%, we will have 240–260 subjects who meet OGTT criteria for GDM. Following regional prevalence, we expect to have 34–37 women who will develop either diabetes or pre-diabetes in the early post-partum period. The sensitivity and specificity of plasma gCD59 to predict the results of the OGTT will be assessed using nonparametric estimates of the receiver operating characteristic (ROC) curves and respective area under the ROC curve (AUROC).DiscussionA body of clinical and experimental evidence supports a link between the complement system, complement regulatory proteins, and the pathogenesis of diabetes complications.Building on this research, our study plans to look at the plasma gCD59 capacity to classify pregnant women with normal or abnormal glucose tolerance but also to assess if plasma gCD59 can be used as an early predictor for GDM, for adverse pregnancy outcomes and/or post-partum glucose intolerance.

Glycated hemoglobin (HbA1c) as diagnostic criteria for diabetes: the optimal cut-off points values for the Pakistani population; a study from second National Diabetes Survey of Pakistan (NDSP) 2016–2017

AimGlycated hemoglobin (HbA1c) cut-off values as diagnostic tool in diabetes and prediabetes with its concordance to oral glucose tolerance test (OGTT) in Pakistani population.MethodologyData for this substudy was obtained from...

Risk of type 2 diabetes mellitus among women with gestational diabetes mellitus in semi-urban area, Thiruvallur district, Tamil Nadu: a case control study

Background: Gestational diabetes mellitus (GDM) is one of the risk factors associated with type 2 diabetes mellitus. Hence early detection by screening and management of GDM is very essential to reduce the burden of type 2 diabetes. Objectives was to evaluate the strength of association of GDM and type 2 diabetes among women aged 30 to 35 years in Thiruvallur District, to find the association of other risk factors with type 2 diabetes.Methods: A study was conducted among 160 women with 44 cases and 116 controls aged 30-35 years attending NCD clinics in Thiruvallur District between March and September 2016. The cases and controls were matched for age and time period between last delivery and the time of screening as 5 years or more. GDM exposure was ascertained if their venous blood glucose levels during their antenatal and postpartum period exceeded the oral glucose tolerance test criteria recommended by national guidelines.Results: In the study it was found that women with history of GDM are 4.65 times higher at risk of developing type 2 diabetes. There was significant association (p=0.000) between type 2 diabetes and risk factors like family history of diabetes, co-morbidities like hypertension, hypothyroidism.Conclusions: Gestational diabetes is a predictor of type 2 diabetes, as the women are registered in the pregnancy and infant cohort monitoring and evaluation system, it has the potential to identify women at risk of type 2 diabetes and intervene at the earliest.

Cholecystectomy is an independent factor of enhanced insulin release and impaired insulin sensitivity

AimsCholecystectomy is a risk factor for insulin resistance and diabetes, but the association between cholecystectomy and insulin release/sensitivity remains obscure. We investigated the association between cholecystectomy and the factors related to glycemia and glucose tolerance. MethodsA cross-sectional study was conducted in 2011 with 10,027 participants aged ≥40 in Nanjing, China. After applying exclusion criteria, 8,030 participants were divided into three groups: 1, without gallbladder disease (n = 6783); 2, with gallbladder disease but without cholecystectomy (n = 857); and 3, with cholecystectomy (n = 390). ResultsVarious indexes of blood glucose and insulin level after the oral glucose tolerance test (OGTT) were assessed. The association between gallbladder disease or cholecystectomy and diabetes was evaluated with logistic regression models. Group 3 had a higher prevalence of newly diagnosed diabetes by OGTT criteria compared with groups 2 and 1, respectively (20.5% vs. 12.4% vs. 10.6%, P < 0.001). The adjusted odds ratio and 95% confidence interval of diabetes associated with cholecystectomy were 1.546 (1.168, 2.046) (P = 0.002). Pattern 2, which was characterized by a lasting late insulin response, was more frequent in group 3 compared with groups 2 and 1, respectively (61.0% vs. 54.3% vs.48.3%, P < 0.001). After adjusting for confounding factors, a higher total insulin release and lower Matsuda insulin sensitivity index (P < 0.001) were found in group 3 compared with the other two groups. ConclusionsCholecystectomized subjects demonstrated a higher prevalence of diabetes characterized by lower peripheral insulin sensitivity and higher total insulin release.

Impact of mismatches in HbA1c vs glucose values on the diagnostic classification of diabetes and prediabetes.

To determine whether HbA1c mismatches (HbA1c levels that are higher or lower than expected for the average glucose levels in different individuals) could lead to errors if diagnostic classification is based only on HbA1c levels. In a cross-sectional study, 3106 participants without known diabetes underwent a 75-g oral glucose tolerance test (fasting glucose and 2-h glucose) and a 50-g glucose challenge test (1-h glucose) on separate days. They were classified by oral glucose tolerance test results as having: normal glucose metabolism; prediabetes; or diabetes. Predicted HbA1c was determined from the linear regression modelling the relationship between observed HbA1c and average glucose (mean of fasting glucose and 2-h glucose from the oral glucose tolerance test, and 1-h glucose from the glucose challenge test) within oral glucose tolerance test groups. The haemoglobin glycation index was calculated as [observed - predicted HbA1c ], and divided into low, intermediate and high haemoglobin glycation index mismatch tertiles. Those participants with higher mismatches were more likely to be black, to be men, to be older, and to have higher BMI (all P<0.001). Using oral glucose tolerance test criteria, the distribution of normal glucose metabolism, prediabetes and diabetes was similar across mismatch tertiles; however, using HbA1c criteria, the participants with low mismatches were classified as 97% normal glucose metabolism, 3% prediabetes and 0% diabetes, i.e. mostly normal, while those with high mismatches were classified as 13% normal glucose metabolism, 77% prediabetes and 10% diabetes, i.e. mostly abnormal (P<0.001). Measuring only HbA1c could lead to under-diagnosis in people with low mismatches and over-diagnosis in those with high mismatches. Additional oral glucose tolerance tests and/or fasting glucose testing to complement HbA1c in diagnostic classification should be performed in most individuals.

Two- vs one-hour glucose tolerance testing: Predicting prediabetes in adolescent girls with obesity.

During an oral glucose tolerance test (OGTT), morphological features of the glucose curve (monophasic curve, glucose peak >30 minutes and 1-hour glucose ≥ 155 mg/dL) maybe associated with higher prediabetes risk, but their reproducibility and predictive ability in adolescents with obesity are unknown. Nondiabetic adolescent girls with obesity underwent a multiple-sample OGTT at baseline (n = 93), 6 weeks (n = 83), and 1 year (n = 72). Short-term reproducibility (baseline to 6 weeks) and the predictive ability for prediabetes (baseline to 1 year) for each feature were compared with standard fasting and 2-hour OGTT diagnostic criteria. There was fair/moderate short-term reproducibility (κ < 0.5) for all morphological features. At 1 year, compared with standard OGTT criteria, the areas under the receiver operating curve (ROC-AUCs) for glucose peak > 30 minutes, 1 hour ≥155 mg/dL or a combination of the two criteria were comparable (all P > 0.05), but the monophasic curve had the lowest ROC-AUC (P < 0.001). In adolescent girls with obesity, glucose peak > 30 minutes and/or glucose ≥155 mg/dL had similar reproducibility and 1-year predictive ability for prediabetes compared with standard OGTT criteria. The shortened 1-hour OGTT may provide diagnostic equivalence for prediabetes risk with the additional advantage of a less time-consuming risk assessment.

Vitamin D Status among Bangladeshi Adult Muslim Females Having Diabetes and Using Hijab

Background: This study was done to evaluate vitamin D level and status among Bangladeshi muslim women and to see association between vitamin D level and residence status, sunlight exposure, glycemic status, using hijab with exposed face and hands.Methods: This cross-section observational study was conducted during January 2015 to July 2017 among 353 Bangladeshi non-pregnant muslim female subjects aged e” 18 years who attended an urban endocrine clinic with complaints of myalgia, fatigability, muscle cramp etc. Subjects who were on vitamin D supplement/ treatment, suffering from mal-absorption syndrome, hepatic impairment, renal impairments, severe co-morbid conditions were excluded. Diabetic subjects were selected as per clinical history, HbA1c%, OGTT (oral glucose tolerance test) criteria or who already were receiving treatment for diabetes. Data were collected by face-toface interview and medical documents review and vitamin D level was tested with standard laboratory procedure. Subjects were enquired about using hijab with exposed face and hands with duration of years. Vitamin D status was defined as “deficient” with level of serum 25 (OH) vit D d”20 ng/ml, “insufficient” with level from 20.01 to 29.9 ng/ml and “sufficient” with level from 30 to 100 ng/ml. Data were analyzed with IBM SPSS for Windows version 20. The significance was tested by using un-paired T test and Chi-square test.Results: A total of 353 Bangladeshi muslim female were studied. Among them 332 (94.1%) were urban dwellers. Mean age was 40.66 ±13.80 years, mean vitamin D level was 17.27±7.47 ng/ml, while 71.67% subjects were vitamin D deficient and 22.66% subjects were insufficient. Residence status (urban and rural) showed no significant association with vitamin D level and status [p 0.074 and p 0.28 respectively]. Vitamin D insufficient subjects were more aged than deficient subjects [p 0.01]. Vitamin D level was not significantly different in regard to difference in sunlight exposure [p 0.70]. Diabetic (46.2%) and non-diabetic (53.8%) subjects had similar residence status [p 0.824]. Diabetic subjects were more aged than non-diabetic subjects [p 0.001] and vitamin D level was not significantly different among them [p 0.126 and p 0.28 respectively]. Among studied subjects 32.9% (n=116), mostly urban dwellers, never used hijab and they had mean vitamin D level as 17.04±7.77 ng/ml, while 30.3% (n=107) subjects used hijab more than 15 years with exposed face and hands and they had mean vitamin D level as 18.52±8.07 ng/ml. Difference of vitamin D levels and vitamin D were not significant among hijab users and non-users [p 0.16 and p 0.13 respectively].Conclusion: The study revealed that most of the studied Bangladeshi muslim female urban dwellers had vitamin D deficiency and insufficiency which was not significantly influenced by glycemic status, residence status, level of sunlight exposure and using hijab. Large scale population based study is needed to elucidate findings of the current study.Birdem Med J 2018; 8(3): 203-209

Prognosis of Intracerebral Hemorrhage with Newly Diagnosed Diabetes Mellitus According to Hemoglobin A1c Criteria

Hemoglobin A1c (HbA1c) has been recommended for diagnosing diabetes mellitus (DM). We aimed to assess the prevalence of newly diagnosed diabetes mellitus (NDDM) in patients with intracerebral hemorrhage (ICH) using HbA1c criteria and to investigate the long-term prognosis of patients with ICH with NDDM. Data of patients with ICH without a DM history were derived from the Abnormal Glucose Regulation in Patients with Acute Stroke across China. NDDM was defined as a fasting plasma glucose (FPG) level of 7.0 mmol/L or higher, a 2-hour oral glucose tolerance test (OGTT) result of 11.1 mmol/L or higher, or an HbA1c level of 6.5% or higher. The prevalence of NDDM with different screening methods was assessed. The association between NDDM and 1-year prognosis (mortality, stroke recurrence, and poor functional outcome [modified Rankin scale score of 3-6]) was estimated. There were 357 patients with ICH included in the analysis, and 131 (36.7%) were diagnosed as NDDM using the new criteria. NDDM was present in 31 (8.7%), 98 (27.5%), and 68 (19.0%) patients with ICH, based on FPG, 2-hour OGTT, and HbA1c criteria, respectively. NDDM was independently associated with 1-year poor functional outcome (odds ratio 1.93; 95% confidence interval, 1.10-3.38, P = .02). Nevertheless, NDDM showed no significant association with 1-year death and stroke recurrence (P > .05 for both). More than one third of patients with ICH without a history of DM were diagnosed NDDM using the new criteria. NDDM by the new criteria was an independent risk factor of poor functional outcome, but not of death and stroke recurrence at 1 year after ICH onset.

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

AimsDue to the diversity of the Chinese population, it requires considerable research to evaluate HbA1c diagnostic threshold for diagnosis of hyperglycemia. MethodsWe 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. ResultsThe 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. ConclusionsThe 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.

Utility and Limitations of Glycated Hemoglobin (HbA1c) in Patients with Liver Cirrhosis as Compared with Oral Glucose Tolerance Test for Diagnosis of Diabetes.

IntroductionTo study the utility of glycated hemoglobin (HbA1c) in the diagnosis of diabetes in patients with cirrhosis as compared to the gold standard oral glucose tolerance test (OGTT) and to see the effect of anemia and severity of cirrhosis on its performance.MethodsIndividuals (n = 100) with an established diagnosis of liver cirrhosis were recruited. The OGTT was performed as described by the World Health Organization (WHO). The severity of cirrhosis was calculated using the Child–Turcotte–Pugh (CTP) score. The severity of anemia was defined according to WHO criteria. The utility of HbA1c was compared against the OGTT results. Test sensitivity and specificity were used to describe the diagnostic accuracy of HbA1c.ResultsA total of 100 subjects aged 46.9 ± 9.1 years (mean ± standard deviation) participated in the study, of whom 65% were recruited from out patient department of our hospital. The overall sensitivity and specificity of a HbA1c level of ≥ 6.5% for the diagnosis of diabetes in patients with cirrhosis was 77.1% (95% CI 59.9, 89.6) and 90.8% (95% CI 81.0, 96.5), respectively. The positive and negative predictive values were 81.8% (95% CI 67.3, 90.8) and 88.1% (95% CI 80.0, 93.2), respectively. The area under the curve was 0.85 (95% CI 0.75–0.94). The sensitivity of HbA1c for diagnosing diabetes in outpatients was 87.0% (95% CI 66.4, 97.2) and was better than that for diagnosing diabetes in hospitalized patients (58.3%; 95% CI 27.7, 84.8). The sensitivity of HbA1c for diagnosing diabetes was poor in patients with moderate to severe anemia. The difference in sensitivity and specificity was not statistically different for CTP classes A, B and C. The prevalence of diabetes as defined by American Diabetes Association OGTT criteria was 35% (95% CI 25.7–45.2%).ConclusionsTaking OGTT as the gold standard, the sensitivity of HbA1c for diagnosing diabetes is good when used in outpatients with cirrhosis. However, the sensitivity of HbA1c decreases when it is used for hospitalized patients, suggesting that it is not a good test for diagnosis of diabetes in such cases. It also performs poorly if the patient has moderate to severe anemia.

Patterns of gestational diabetes diagnosis inside and outside of clinical guidelines

BackgroundHospital discharge codes are often used to determine the incidence of gestational diabetes mellitus (GDM) at state and national levels. Previous studies demonstrate substantial variability in the accuracy of GDM reporting, and rarely report how the GDM was diagnosed. Our aim was to identify deliveries coded as gestational diabetes, and then to determine how the diagnosis was assigned and whether the diagnosis followed established guidelines.MethodsWe identified which deliveries were coded at discharge as complicated by GDM at the Brigham and Women’s Hospital in Boston, MA for the year 2010. We reviewed medical records to determine whether the codes were appropriately assigned.ResultsOf 7883 deliveries, coding for GDM was assigned with 98% accuracy. We identified 362 cases assigned GDM delivery codes, of which 210 (58%) had oral glucose tolerance test (OGTT) results available meeting established criteria. We determined that 126 cases (34%) received a GDM delivery code due to a clinician diagnosis documented in the medical record, without an OGTT result meeting established guidelines for GDM diagnosis. We identified only 15 cases (4%) that were coding errors.ConclusionsThirty four percent of women assigned GDM delivery codes at discharge had a medical record diagnosis of GDM but did not meet OGTT criteria for GDM by established guidelines. Although many of these patients may have met guidelines if guideline-based testing had been conducted, our findings suggest that clinician diagnosis outside of published guidelines may be common. There are many ramifications of this approach to diagnosis, including affecting population-level statistics of GDM prevalence and the potential impact on some women who may be diagnosed with GDM erroneously.

Performance of the Finnish Diabetes Risk Score and a Simplified Finnish Diabetes Risk Score in a Community-Based, Cross-Sectional Programme for Screening of Undiagnosed Type 2 Diabetes Mellitus and Dysglycaemia in Madrid, Spain: The SPREDIA-2 Study

AimTo evaluate the performance of the Finnish Diabetes Risk Score (FINDRISC) and a simplified FINDRISC score (MADRISC) in screening for undiagnosed type 2 diabetes mellitus (UT2DM) and dysglycaemia.MethodsA population-based, cross-sectional, descriptive study was carried out with participants with UT2DM, ranged between 45–74 years and lived in two districts in the north of metropolitan Madrid (Spain). The FINDRISC and MADRISC scores were evaluated using the area under the receiver operating characteristic curve method (ROC-AUC). Four different gold standards were used for UT2DM and any dysglycaemia, as follows: fasting plasma glucose (FPG), oral glucose tolerance test (OGTT), HbA1c, and OGTT or HbA1c. Dysglycaemia and UT2DM were defined according to American Diabetes Association criteria.ResultsThe study population comprised 1,426 participants (832 females and 594 males) with a mean age of 62 years (SD = 6.1). When HbA1c or OGTT criteria were used, the prevalence of UT2DM was 7.4% (10.4% in men and 5.2% in women; p<0.01) and the FINDRISC ROC-AUC for UT2DM was 0.72 (95% CI, 0.69–0.74). The optimal cut-off point was ≥13 (sensitivity = 63.8%, specificity = 65.1%). The ROC-AUC of MADRISC was 0.76 (95% CI, 0.72–0.81) with ≥13 as the optimal cut-off point (sensitivity = 84.8%, specificity = 54.6%). FINDRISC score ≥12 for detecting any dysglycaemia offered the best cut-off point when HbA1c alone or OGTT and HbA1c were the criteria used.ConclusionsFINDRISC proved to be a useful instrument in screening for dysglycaemia and UT2DM. In the screening of UT2DM, the simplified MADRISC performed as well as FINDRISC.

The 1-hour post-load glucose level is more effective than HbA1c for screening dysglycemia.

To assess the performance of HbA1c and the 1-h plasma glucose (PG≥155mg/dl; 8.6mmol/l) in identifying dysglycemia based on the oral glucose tolerance test (OGTT) from a real-world clinical care setting. This was a diagnostic test accuracy study. For this analysis, we tested the HbA1c diagnostic criteria advocated by the American Diabetes Association (ADA 5.7-6.4%) and International Expert Committee (IEC 6.0-6.4%) against conventional OGTT criteria. We also tested the utility of 1-h PG≥mg/dl; 8.6mmol/l. Prediabetes was defined according to ADA-OGTT guidelines. Spearman correlation tests were used to determine the relationships between HbA1c, 1-h PG with fasting, 2-h PG and indices of insulin sensitivity and β-cell function. The levels of agreement between diagnostic methods were ascertained using Cohen's kappa coefficient (Κ). Receiver operating characteristic (ROC) curve was used to analyze the performance of the HbA1c and 1-h PG test in identifying prediabetes considering OGTT as reference diagnostic criteria. The diagnostic properties of different HbA1c thresholds were contrasted by determining sensitivity, specificity and likelihood ratios (LR). Of the 212 high-risk individuals, 70 (33%) were identified with prediabetes, and 1-h PG showed a stronger association with 2-h PG, insulin sensitivity index, and β-cell function than HbA1c (P<0.05). Furthermore, the level of agreement between 1-h PG≥155mg/dl (8.6mmol/l) and the OGTT (Κ[95% CI]: 0.40[0.28-0.53]) diagnostic test was stronger than that of ADA-HbA1c criteria 0.1[0.03-0.16] and IEC criteria (0.17[0.04-0.30]). The ROC (AUC[95% CI]) for HbA1c and 1-h PG were 0.65[0.57-0.73] and 0.79[0.72-0.85], respectively. Importantly, 1-h PG≥155mg/dl (8.6mmol/l) showed good sensitivity (74.3% [62.4-84.0]) and specificity 69.7% [61.5-77.1]) with a LR of 2.45. The ability of 1-h PG to discriminate prediabetes was better than that of HbA1c (∆AUC: -0.14; Z value: 2.5683; P=0.01022). In a real-world clinical practice setting, the 1-h PG≥155mg/dl (8.6mmol/l) is superior for detecting high-risk individuals compared with HbA1c. Furthermore, HbA1c is a less precise correlate of insulin sensitivity and β-cell function than the 1-h PG and correlates poorly with the 2-h PG during the OGTT.

Metabolic Profile of Persons with Newly Diagnosed Diabetes Using either Glycoslated Haemoglobin or Oral Glucose Tolerance Test in Primary Prevention Trials in Asian Indians

Background: To compare cardio metabolic characteristics of Asian Indians with incident type 2 diabetes diagnosed by Oral Glucose Tolerance Test (OGTT) or by Glycosylated Haemoglobin (HbA1c). Research Design and Methods: Data from two Indian Diabetes Prevention Studies in persons with Impaired Glucose Tolerance (IGT) was used. In 314 persons, diabetes was diagnosed by OGTT and another 67 persons had only HbA1c values ≥ 6.5% (≥48 mmol/mol). Cardiometabolic characteristics were compared in 3 sub-groups-1: Persons with positive OGTT only (HbA1c<6.5% (<48 mmol/mol) (n=125), 2: Persons with positive HbA1c but negative OGTT (n=67), 3: Those with both HbA1c and OGTT positive (n=189). Results: Diagnostic sensitivity of HbA1c was 67.2% when compared with OGTT criteria. Prevalence of obesity, abdominal obesity, hypertension, insulin resistance and lipid abnormalities were similar in all groups. Persons in groups-1 and 2 had similar metabolic characteristics, but for higher plasma glucose in the former group and higher HbA1c in the latter group. Prevalence of abnormalities was similar in both groups. Group with both the tests positive, had higher levels of insulin resistance. Conclusion: Metabolic characteristics of incident diabetic cases identified either by OGTT or by HbA1c were similar, except for a higher prevalence of insulin resistance among those who had both tests positive.

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.

An Early Pregnancy HbA1c ≥5.9% (41 mmol/mol) Is Optimal for Detecting Diabetes and Identifies Women at Increased Risk of Adverse Pregnancy Outcomes

Unrecognized diabetes in parturients can cause poor obstetric outcomes. Several professional associations recommend screening for diabetes in pregnancy at the first antenatal visit, although the most appropriate test and threshold remain unclear. Measurement of hemoglobin A1c (HbA1c) can be added to the routine early pregnancy tests, with a level of 6.5% or greater (48 mmol/mol) recommended as the diagnostic cutoff for diabetes. However, the optimal threshold in pregnancy is likely lower. This prospective cohort study was performed to determine the optimal early pregnancy HbA1c threshold to detect diabetes and whether this threshold identifies women at increased risk of adverse pregnancy outcomes. The association of the HbA1c levels was compared with diagnoses of preexisting diabetes or gestational diabetes mellitus (GDM) as measured by the standard oral glucose tolerance test (OGTT) performed at less than 20 weeks’ gestation. Diabetes was defined as fasting ≥126 mg/dL (7.0 mmol/L) or 2 hours ≥200 mg/dL (11.1 mmol/L) and GDM as fasting ≥92 mg/dL (5.1 mmol/L), 1 hour ≥180 mg/dL (10.0 mmol/L), or 2 hours ≥153 mg/dL (8.5 mmol/L). Women were referred for management of GDM only when fasting levels were ≥99 mg/dL (5.5 mmol/L) or 2 hours ≥162 mg/dL (9.0 mmol/L). HbA1c testing was performed for 16,122 women at a median of 47 days’ (interquartile range, 38–62 days’) gestation. The mean ± SD HbA1c level was 5.3% ± 0.3% (34 ± 3.3 mmol/mol); 33 (0.2%) women had HbA1c of 6.5% or greater (48 mmol/mol). The OGTTs were performed at less than 20 weeks in 974 of 4201 women at a median of 99 days (interquartile range, 84–113 days). Fifteen women met the OGTT criteria for diabetes, with a median HbA1c of 6.5% (48 mmol/mol; range, 5.9%–8.9%; 41–74 mmol/mol). The OGTT criteria for GDM were met by 170 women at less than 20 weeks, with a median HbA1c of 5.8% (40 mmol/mol; range, 4.8%–7.3%; 29–56 mmol/mol). The optimal HbA1c screening threshold for detecting diabetes was 5.9% or greater (41 mmol/mol) and was met by 2.9% of the total cohort. Sensitivity was 100% (95% confidence interval [CI], 91.8%–100%), specificity 97.4% (95% CI, 95.5%–99.2%), positive predictive value 18.8% (95% CI 15.7%–22.4%), and negative predictive value 100% (95% CI, 100%–100%). For early GDM, this HbA1c threshold was highly specific at 98.4% (95% CI, 97.0–99.9), but less sensitive at 18.8% (95% CI, 6.6%–31.1%). In total, 128 women (74.0%) with early HbA1c of 5.9% or greater who had an OGTT met GDM criteria at some point in the pregnancy; 18 (10.4%) of these women met diabetes criteria. Seventy-three of 78 patients had a postnatal OGTT; 34 (46.6%) were abnormal, 10 (13.7%) had diabetes, 24 (32.9%) had impaired glucose tolerance, and 8 (11.0%) had impaired fasting glucose (100–109 mg/dL; 5.6–6.0 mmol/L). Of the 29 women with HbA1c of 6.5% or greater at less than 20 weeks, 25 (86.2%) had a postnatal OGTT, 20 (80%) had diabetes, and 5 (20%) had impaired glucose tolerance. Compared with women with HbA1c of less than 5.9%, those with HbA1c of 5.9% or greater had more than 2-fold increased relative risk (RR) of preeclampsia, shoulder dystocia, and major congenital anomaly; more than a 3-fold increased RR of perinatal death; and more than a 1.5-fold increased RR of delivery at less than 37 weeks. Four perinatal deaths occurred for women with HbA1c of 5.9% to 6.4% who received routine pregnancy care. Hemoglobin A1c of 5.9% or greater identified all women with diabetes in those who had an OGTT at less than 20 weeks’ gestation. A threshold of 6.5% or greater would have missed almost 50% of these parturients and is thus too high for screening purposes. Future studies are needed to confirm these results and to assess the impact of early detection and treatment on maternal and fetal outcomes and the cost-effectiveness of HbA1c compared with OGTT.

The discordance between HbA1c and glucose tolerance testing for the postpartum exclusion of diabetes following gestational diabetes

AimsTo assess the concordance between the HbA1c and the oral glucose tolerance test (OGTT) for the diagnosis of diabetes and prediabetes following gestational diabetes (GDM) in an ethnically diverse population. MethodsWomen with GDM underwent a concurrent OGTT and HbA1c test 6–12 weeks postpartum. ResultsThere were 114 women with GDM who had a 75g 2-h OGTT and HbA1c at 9.0±3.2 weeks postpartum. Five subjects had diabetes using OGTT criteria, and 4 by HbA1c criteria. No subjects had diabetes on both criteria. The overall concordance between the OGTT and HbA1c for the diagnosis of diabetes, prediabetes, or normal glucose tolerance was only 54% (κ coefficient 0.058, p=0.41). Gravidity, the 2-h glucose level on the OGTT during pregnancy, and the 3rd trimester HbA1c predicted discordance between the postpartum OGTT and HbA1c. ConclusionsThere is poor concordance between the OGTT and HbA1c for the diagnosis of diabetes and prediabetes following GDM. This reflects that the two tests measure different aspects of dysglycemia. In the post-GDM population, the HbA1c misses cases of diabetes as identified by the OGTT. We recommend that the OGTT be retained for postpartum diabetes testing following GDM.

Role of HbA1c in post-partum screening of women with gestational diabetes mellitus

AimTo compare the performance of HbA1c with established glucose criteria during an oral glucose tolerance test (OGTT) and to assess HbA1c as a screening test for undiagnosed diabetes and pre-diabetes after gestational diabetes mellitus (GDM). MethodsGlucose homeostasis was re-evaluated 1–5 years after delivery in 140 women with previous GDM, by means of OGTT and simultaneous HbA1c measurement. Glucose tolerance was defined according to World Health Organisation criteria. HbA1c ≥6.5% (≥48 mmol/mol) was used for diabetes diagnosis and HbA1c ≥5.7% (≥39 mmol/mol) to define abnormal glucose homeostasis. ResultsHbA1c had low sensitivity (14.3%) and high specificity (99.1%) in diabetes diagnosis. Sensitivity and specificity of HbA1c to detect abnormal glucose tolerance were 29.5% and 95.2%, respectively. The consistency in classifying abnormal glucose tolerance between HbA1c and OGTT criteria was 59% (κ = 0.227) and the area under the receiver operating characteristic curve was 0.708. The combined use of HbA1c and fasting glucose criteria showed similar performance to that of fasting glucose criteria alone. The latter identified 63% of the women with pre-diabetes or diabetes in the study cohort. However, by lowering the cut-point of HbA1c to ≥5.0% (≥31 mmol/mol), an additional proportion (27%) with isolated post-glucose load hyperglycaemia was identified. ConclusionProposed thresholds of HbA1c had low diagnostic sensitivity. Combined with a fasting glucose test, the performance was no better than with using a fasting glucose test alone. Combining a fasting glucose test with a lower HbA1c cut-point may be an alternative approach for selection of women for an OGTT.