Should glycated haemoglobin (HbA1c) be used to detect people with type 2 diabetes mellitus and impaired glucose regulation?

Emerging biosensor probes for glycated hemoglobin (HbA1c) detection

Glycated hemoglobin (HbA1c), originating from the non-enzymatic glycosylation of βVal1 residues in hemoglobin (Hb), is an essential biomarker indicating average blood glucose levels over a period of 2 to 3 months without external environmental disturbances, thereby serving as the gold standard in the management of diabetes instead of blood glucose testing. The emergence of HbA1c biosensors presents affordable, readily available options for glycemic monitoring, offering significant benefits to small-scale laboratories and clinics. Utilizing nanomaterials coupled with high-specificity probes as integral components for recognition, labeling, and signal transduction, these sensors demonstrate exceptional sensitivity and selectivity in HbA1c detection. This review mainly focuses on the emerging probes and strategies integral to HbA1c sensor development. We discussed the advantages and limitations of various probes in sensor construction as well as recent advances in diverse sensing strategies for HbA1c measurement and their potential clinical applications, highlighting the critical gaps in current technologies and future needs in this evolving field.

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

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

Is There a Relationship between Optic Nerve and Chiasm Measurements with HbA1c Levels in Diabetic Patients?

Objectives  We investigated the optic nerve (ON) and chiasm (OC) in magnetic resonance (MR) in diabetic patients by comparing them with hemoglobin A1c (HbA1c) levels. Methods  In this retrospective study, cranial MRIs of 42 adults (19 males and 23 females) with diabetes mellitus (DM) (group1) and 40 healthy controls (19 males and 21 females) (group 2) were included. In both groups, bilateral ON widths and OC area, width, and height were measured. In the DM group, HbA1c values were also obtained at the time of MRI or within the same month. Results  In the DM group, the mean of the HbA1c values was 8.31 ± 2.51%. There were no significant differences between ON diameter; and OC area, width and height of the DM and control groups ( p  > 0.05). In each of the DM and control groups, ON diameter was not different between the right and left sides ( p  > 0.05). In DM groups, correlation tests showed that there were positive correlations between right and left ON diameters, OC area and OC width, and OC height ( p  < 0.05). In males, ON diameters were higher than those in females bilaterally ( p  < 0.05). In patients with higher HbA1c values, OC width was smaller ( p  < 0.05). Conclusion  A significant correlation of OC width and HbA1c levels suggests that uncontrolled DM causes ON atrophy. Our study represents a thorough assessment of OC measures using standard brain MRI to evaluate optic degeneration in DM patients and shows that the OC width measurement is suitable and reliable. This simple method can be obtained from clinically available scans.

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.

Ferrocene-Labelled Electroactive Aptamer-Based Sensors (Aptasensors) for Glycated Haemoglobin

Glycated haemoglobin (HbA1c) is a diagnostic biomarker for type 2 diabetes. Traditional analytical methods for haemoglobin (Hb) detection rely on chromatography, which requires significant instrumentation and is labour-intensive; consequently, miniaturized devices that can rapidly sense HbA1c are urgently required. With this research, we report on an aptamer-based sensor (aptasensor) for the rapid and selective electrochemical detection of HbA1c. Aptamers that specifically bind HbA1c and Hb were modified with a sulfhydryl and ferrocene group at the 3' and 5'-end, respectively. The modified aptamers were coated through sulfhydryl-gold self-assembly onto screen printed electrodes, producing aptasensors with built in electroactivity. When haemoglobin was added to the electrodes, the current intensity of the ferrocene in the sensor system was reduced in a concentration-dependent manner as determined by differential pulse voltammetry. In addition, electrochemical impedance spectroscopy confirmed selective binding of the analytes to the aptamer-coated electrode. This research offers new insight into the development of portable electrochemical sensors for the detection of HbA1c.

Which Hyperglycemic Model of Zebrafish (Danio rerio) Suites My Type 2 Diabetes Mellitus Research? A Scoring System for Available Methods

Despite extensive studies on type 2 diabetes mellitus (T2DM), there is no definitive cure, drug, or prevention. Therefore, for developing new therapeutics, proper study models of T2DM is necessary to conduct further preclinical researches. Diabetes has been induced in animals using chemical, genetic, hormonal, antibody, viral, and surgical methods or a combination of them. Beside different approaches of diabetes induction, different animal species have been suggested. Although more than 85% of articles have proposed rat (genus Rattus) as the proper model for diabetes induction, zebrafish (Danio rerio) models of diabetes are being used more frequently in diabetes related studies. In this systematic review, we compare different aspects of available methods of inducing hyperglycemia referred as T2DM in zebrafish by utilizing a scoring system. Evaluating 26 approved models of T2DM in zebrafish, this scoring system may help researchers to compare different T2DM zebrafish models and select the best one regarding their own research theme. Eventually, glyoxalase1 (glo1-/-) knockout model of hyperglycemia achieved the highest score. In addition to assessment of hyperglycemic induction methods in zebrafish, eight most commonly proposed diabetic induction approval methods are suggested to help researchers confirm their subsequent proposed models.

One-hour plasma glucose concentration can identify elderly Chinese male subjects at high risk for future type 2 diabetes mellitus: A 20-year retrospective and prospective study

AIM

There have been few reports regarding the association between 1 h-PG concentration and type 2 diabetes mellitus (T2DM) in the elderly. This study was performed to assess the efficacy of 1 h-PG and 2 h-PG values in predicting future risk of T2DM in elderly.

METHODS

The study population consisted of 928 male volunteers ≥ 55 years old without diabetes who were involved in a retrospective-prospective cohort study over 20 years with a baseline fasting plasma glucose (FPG) and OGTT that included measurement of 1 h-PG and 2 h-PG. The predictive capabilities of FPG and 1 h-PG, 2 h-PG values obtained during OGTT alone and added to a clinical prediction model consisting of traditional diabetes risk factors were assessed.

RESULTS

Overall, 577 of all the 928 study participants (62%) developed T2DM over the 20-year follow-up. 1 h-PG and 2 h-PG values predicted T2DM and remained independent predictors of T2DM after adjusting for various traditional risk factors [HR = 1.269 (95% CI = 1.214-1.327), P < 0.001; HR = 1.269 (95% CI = 1.179-1.366), P < 0.001, respectively]. C-statistics for 1-h PG (C-statistics 0.794 [95% CI 0.765-0.823]) was significantly greater than that for 2-h PG (C-statistic 0.747 [95% CI 0.716-0.779]) in models adjusting for various traditional risk factors. 1 h-PG had the greatest area under the ROC curve (AUC, 0.766), which was greater than that of 2 h-PG (0.719).

CONCLUSIONS

1 h-PG is useful as a predictor of future development of T2DM independently of traditional risk factors in an elderly Chinese male population.

Glycemic Measures and Risk of Mortality in Older Chinese: The Guangzhou Biobank Cohort Study

CONTEXT

China has the largest number of people with type 2 diabetes mellitus (T2DM) in the world. Data from previous studies have suggested that up to one-fifth of individuals with diabetes would be missed without an oral glucose tolerance test (OGTT). To date, there is little information on the mortality risk of these individuals.

OBJECTIVE

We estimated the association of different indicators of hyperglycemia with mortality in the general Chinese population.

DESIGN

Prospective cohort study.

SETTING

China.

PARTICIPANTS

A total of 17 939 participants aged 50+ years.

EXPOSURES

Previously diagnosed diabetes and newly detected diabetes defined by fasting glucose (≥7.0 mmol/L), 2-hour postload glucose (≥11.1 mmol/L), or hemoglobin A1c (HbA1c, ≥6.5%).

MAIN OUTCOMES MEASURES

Deaths from all-cause, cardiovascular disease, and cancer were identified by record linkage with death registration.

RESULTS

During 7.8 (SD, 1.5) years' follow-up, 1439 deaths were recorded. Of 3706 participants with T2DM, 2126 (57%) had known T2DM, 118 (3%) were identified by isolated elevated fasting glucose, 1022 (28%) had isolated elevated postload glucose, and 440 (12%) had both elevated fasting and postload glucose. Compared with normoglycemia, the hazard ratio (95% confidence interval) of all-cause mortality was 1.71 (1.46-2.00), 0.96 (0.47-1.93), 1.43 (1.15-1.78), and 1.82 (1.35-2.45) for the 4 groups, respectively. T2DM defined by elevated HbA1c was not significantly associated with all-cause mortality (hazard ratio, 1.17; 95% confidence interval, 0.81-1.69).

CONCLUSION

Individuals with isolated higher 2-h postload glucose had a higher risk of mortality by 43% than those with normoglycemia. Underuse of OGTT leads to substantial underdetection of individuals with a higher mortality risk and lost opportunities for early intervention.

Marked differences in prediabetes- and diabetes-associated comorbidities between men and women-Epidemiological results from a general population-based cohort aged 6-80 years-The LEAD (Lung, hEart, sociAl, boDy) study

BACKGROUND

Based on biological and behavioural diversity sex and gender may affect comorbidities associated with prediabetes and diabetes. Besides evaluating the prevalence of prediabetes and diabetes (using fasting plasma glucose and HbA1_c levels), the primary aim of the study is to investigate sex and gender differences in the prevalence of comorbidities in subjects with prediabetes and diabetes and to identify possible risk factors associated with prediabetes and diabetes.

DESIGN

This observational, population-based cohort study included 11.014 subjects aged 6-80 years. Examinations included blood samples, ankle-brachial index, ECG, dual-energy X-ray absorptiometry scan and an interviewer-administered questionnaire.

RESULTS

Across all ages, prevalence of prediabetes was 20.2% (male 23.6%; female 17.1%), and 5.4% for diabetes (male 7.3%; female 3.7%). The prevalence of prediabetes ranged from 4.4% (6-<10 years) up to 40.4% (70+ years) in men and from 4.8% up to 42.3% in women. Comorbidity profile was markedly different between male and female, particularly in those with prediabetes: women more often suffered from arrhythmia, noncoronary artery disease, osteoporosis, increased systemic inflammatory biomarkers and depression, while men with prediabetes more often showed angina pectoris, myocardial infarction and media sclerosis.

CONCLUSIONS

The unexpected 4.6% prevalence of prediabetes in children aged 6-10 underscores the need for population-based studies across all ages and the onset of prevention of diabetes at a young age. Marked differences have been found in comorbidities as men with prediabetes and diabetes more often suffer from cardiovascular disease, while women more often show arrhythmia, noncoronary artery disease, increased systemic inflammatory biomarkers and depression.

Associations of growth from birth to puberty with glycemic indicators at ~17.5 years: Evidence from Hong Kong's "Children of 1997" birth cohort

BACKGROUND

From an evolutionary biology perspective, where growth and reproduction trade-off against longevity, we assessed the associations of growth from birth to puberty by phase with later glycemic indicators and any differences by sex.

METHODS

In the population-representative Hong Kong Chinese "Children of 1997" birth cohort (n = 8327), the relation of initial size (weight-for-age z score (WAZ) at birth, length/height-for-age z score (LAZ) at 3 months or body-mass-index-for-age z score (BAZ) at 3 months based on the World Health Organization growth standards/references) and growth at different phases (WAZ gains from 0 to 2 and 2 to 8 years, LAZ or BAZ gains from 3 months to 3 years, 3 to 8 years and 8 to 14 years) with fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) at ~17.5 years, was assessed using adjusted partial least squares regression. Additional analyses further considered growth in late and early infancy.

RESULTS

This study included 3276 of the cohort participants. Higher WAZ gain from 2 to 8 years, LAZ and BAZ gains from 3 to 8 years were consistently associated with higher FPG, adjusted for maternal and infant characteristics, family history of diabetes and household income. Also, higher BAZ gain from 3 to 8 years was associated with higher HbA1c. These associations did not differ by sex.

CONCLUSIONS

Our findings suggest different mechanisms could underlie the pathogenesis of glucose intolerance. Factors that drive specific growth at different phases need to be evaluated to better inform child growth management for long-term health outcomes.

Gestational diabetes mellitus increases the detection rate and the number of oral bacteria in pregnant women

In the present study, we aimed to investigate the association between gestational diabetes mellitus (GDM) and the oral microbial imbalance in the second trimester of pregnancy.Three hundred thirtyone women in the second trimester of pregnancy who underwent prenatal examinations at the Third Affiliated Hospital of Soochow University from February 2018 to August 2018 were included in this study. Personal parameters including the age, education level, and body mass index (BMI) at 28 weeks of gestation were recorded. Gestational diabetes mellitus (GDM) was diagnosed according to the Standards of Medical Care in Diabetes-2011 recommended by American Diabetes Association (ADA). After the significant difference of each parameter was erased by a propensity-score matched (PSM) analysis at a 1:1 ratio, the oral health conditions and the oral flora in pregnant women with GDM were compared with those in nondiabetic pregnant women.Our data demonstrated that 65 of the 331 pregnant women (19.6%) were diagnosed with GDM. Results from the matched data including 59 matched pairs of pregnant women showed that the gingival index (GI), plaque index (PI), tooth mobility degree (TMD), probing depth (PD), and bleeding on probing (BOP) of pregnant women with GDM were higher or more severe than those of nondiabetic pregnant women (P < .05). The detection rate of tuberculosis bacilli, Black-pigmented bacteria, and Capnocytophaga in pregnant women with GDM was higher than those in nondiabetic pregnant women (P = .000, P = .026, and P = .030, respectively). In addition, pregnant women with GDM had fewer oral streptococci (P = .000) and lactobacilli (P = .000) and more oral anaerobic bacteria (P = .000), tuberculosis bacilli (P = .000), Black-pigmented bacteria (P = .007), Capnocytophaga (P = .000), and actinomycetes (P = .000).The detection rate and the number of oral bacteria in pregnant women with GDM were higher than those in nondiabetic pregnant women in the second trimester of pregnancy.

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

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

Haemoglobin A1c as a screening tool for type 2 diabetes and prediabetes in populations of Swedish and Middle-East ancestry

AIMS

To explore and compare sensitivity and specificity for HbA1c ≥48mmol/mol as a predictor for type 2 diabetes mellitus (T2DM) in two populations with different ethnicity and to examine the predictive value of two levels of HbA1c (≥42mmol/mol, ≥39mmol/mol) for prediabetes in these populations.

METHODS

Four cohorts were examined with an oral glucose tolerance test. (1) The MEDIM Study (n=1991 individuals of Swedish and Iraqi ancestry); (2) The Skaraborg Project (n=1327 individuals of Swedish ancestry); (3) The 4-D study (n=424 individuals of Swedish, Iraqi and Turkish ancestry); (4) The Flemingsberg study (n=212 participants of Turkish ancestry).

RESULTS

HbA1c ≥48mmol/mol had a sensitivity for T2DM of 31% and 25% respectively in individuals of Middle-East and Swedish ancestry. The positive and negative predictive value was high in both populations (70.3, 96.4 and 96.2, 97.6 respectively). Using HbA1c ≥42mmol/mol and ≥39mmol/mol as a predictor for prediabetes gave a sensitivity of 17% and 36% in individuals of Middle-East and 15% and 34% in individuals of Swedish ancestry.

CONCLUSIONS

Even if HbA1c ≥48mmol/mol is a valuable diagnostic tool, it is a blunt and insensitive tool for screening and would exclude most people with T2DM, independent of ancestry and age. HbA1c is an inefficient way to detect individuals with prediabetes.

Differentially expressed haptoglobin as a potential biomarker for type 2 diabetic mellitus in Hispanic population

Glycosylated hemoglobin (HbA1c) measurement is currently a primary tool for diagnosis of type 2 diabetes mellitus (T2DM), especially for the assessment of chronic hyperglycemia. However, many studies reported the limitation of using HbA1c for T2DM diagnosis/prognosis, such as poor sensitivities, difficult standardization, and variable cut points across ethnic groups. Therefore, the aim of this study was to discover novel biomarkers associated with elevated HbA1c levels as complementary T2DM diagnostic tools. Two-dimensional difference gel electrophoresis combined with mass spectrometry were applied for protein profile analyses of two pooled serum samples collected from Hispanic T2DM subjects (n = 74) with HbA1c ≥7 and HbA1c< 7, respectively. Isoforms of haptoglobin (Hp) α1/α2 chains were significantly altered in pooled serum samples from T2DM subjects with HbA1c ≥7 compared to those with HbA1c< 7. Hp genotypes of 262 Hispanic subjects, including 109 T2DM and 153 nondiabetic controls, were further determined by PCRs and western blotting analysis. Meanwhile, a new droplet digital PCR method for Hp genotyping was also established. The distribution of Hp2 allele was higher in T2DM subjects compared to nondiabetic controls and the HbA1c levels of T2DM subjects carrying at least one Hp2 allele tended to be higher than T2DM subjects with Hp 1-1. In summary, our results indicate that differentially expressed serum Hp protein isoforms could be associated with HbA1c levels and subjects with Hp2 allele have a higher risk for the occurrence of T2DM in Hispanic population. © 2016 BioFactors, 43(3):424-433, 2017.

Glycemic markers and relation with arterial stiffness in Caucasian subjects of the MARK study

Background

Effect of prediabetes and normal glucose on arterial stiffness remains controversial. The primary aim of this study was to investigate the relationship of fasting plasma glucose (FPG), postprandial glucose (PG) and glycosylated haemoglobin (HbA1c) with brachial-ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI) in Caucasian adults. The secondary aim was to analyse this relationship by glycaemic status.

Methods

Cross-sectional study. Setting: Primary care. Participants: 2,233 subjects, 35–74 years. Measures: FPG (mg/dL) and HbA1c (%) of all subjects were measured using standard automated enzymatic methods. PG (mg/dL) was self-measured at home two hours after meals (breakfast, lunch and dinner) for one day using an Accu-chek ^® glucometer. CAVI was measured using a VaSera VS-1500^® device (Fukuda Denshi), and baPWV was calculated using a validated equation.

Results

CAVI and baPWV values were significantly higher in subjects with diabetes mellitus than in glucose normal and prediabetes groups (p<0.001). FPG, PG and HbA1c were positively associated with CAVI and baPWV. The β regression coefficient for: HbA1c was 0.112 (CI 95% 0.068 to 0.155) with CAVI, 0.266 (CI 95% 0.172 to 0.359) with baPWV; for PG was 0.006 (CI 95% 0.004 to 0.009 and for FPG was 0.005 (CI 95% 0.002 to 0.008) with baPWV; and for PG was 0.002 (CI 95% 0.001 to 0.003) and 0.003 (CI 95% 0.002 to 0.004) with CAVI (p<0.01 in all cases). When analysing by hyperglycaemic status, FPG, PG and HbA1c were positively associated with CAVI and baPWV in subjects with type 2 diabetes mellitus.

Conclusion

FPG, PG and HbA1c show a positive association with CAVI and baPWV, in Caucasian adults with intermediate cardiovascular risk factors. When analysing by hyperglycaemic status, the association is only maintained in subjects with type 2 diabetes mellitus.

Trial registration

Clinical Trials.gov Identifier: NCT01428934. Registered 2 September 2011. Retrospectively registered. Last updated September 8, 2016.

The Importance and Utility of Hemoglobin A1c Levels in the Assessment of Donor Pancreas Allografts

BACKGROUND

Hemoglobin A1C (HbA1c) levels are often obtained in potential pancreas graft donors to assess the overall long-term functional glycemic control or the possibility of unrecognized diabetes. Although routinely measured, the impact of donor HbA1c levels on pancreas graft outcomes has not been reported. Here, we researched the relationship between donor HbA1c levels and postoperative pancreas graft survival.

METHODS

Data from 266 pancreas transplant patients including 182 simultaneous kidney-pancreas and 84 pancreas alone transplants were reviewed for the study. The patients were separated into groups according to their HbA1c levels (5 groups: HbA1c < 5.0, 5.0-5.4, 5.5-5.9, ≥6.0 % and not available, or 2 groups: HbA1c <5.7, ≥5.7%). Overall, death-censored and technically successful pancreas graft survival and rejection rates of each group were compared. In the case of technically successful graft survival, graft losses due to technical problems in the first 60 days were excluded.

RESULTS

All groups were similar with regard to donor variables including age, sex, ABO blood type, ethnicity, donor type and recipient variables including recipient age, sex, induction agents and maintenance treatment. Mean follow-up time was 4.2 ± 1.97 years. The overall graft survivals and death censored graft survivals among groups were not statistically different from one other (P > 0.05). Additionally, excluding early technical losses in 18 patients did not reveal any differences in graft survivals. Patient survival and biopsy-proven acute rejections were statistically similar among HbA1c strata.

CONCLUSIONS

This univariate retrospective analysis of a single center/organ procurement organization use of HbA1c shows that donor HbA1c levels between 3.5 and 6.2 in otherwise transplantable pancreata are not associated with different short-term outcomes.

Diabetes mellitus in Nigeria: The past, present and future

Diabetes mellitus (DM) is a diverse group of metabolic disorders that is often associated with a high disease burden in developing countries such as Nigeria. In the early nineties, not much was known about DM in Nigeria and traditionally, people related DM to "curses" or "hexes" and diagnosis was made based on blood or urinary tests for glucose. Currently, oral hypoglycaemic agents but not insulin are readily accessible and acceptable to persons with DM. The cost of diabetes care is borne in most instances by individuals and often payment is "out of pocket"-this being a sequel of a poorly functional national health insurance scheme. An insulin requiring individual on a minimum wage would spend 29% of his monthly income on insulin. Complementary and alternative medicines are widely used by persons with DM and form an integral component of DM care. Towards reducing the burden of DM in Nigeria, we suggest that there be concerted efforts by healthcare professionals and stakeholders in the health industry to put in place preventative measures, a better functioning health insurance scheme and a structured DM program.

Body mass index and waist circumference cut-points in multi-ethnic populations from the UK and India: the ADDITION-Leicester, Jaipur heart watch and New Delhi cross-sectional studies

Aims

To derive cut-points for body mass index (BMI) and waist circumference (WC) for minority ethnic groups that are risk equivalent based on endogenous glucose levels to cut-points for white Europeans (BMI 30 kg/m²; WC men 102 cm; WC women 88 cm).

Materials and Methods

Cross-sectional data from participants aged 40–75 years: 4,672 white and 1,348 migrant South Asian participants from ADDITION-Leicester (UK) and 985 indigenous South Asians from Jaipur Heart Watch/New Delhi studies (India). Cut-points were derived using fractional polynomial models with fasting and 2-hour glucose as outcomes, and ethnicity, objectively-measured BMI/WC, their interaction and age as covariates.

Results

Based on fasting glucose, obesity cut-points were 25 kg/m² (95% Confidence Interval: 24, 26) for migrant South Asian, and 18 kg/m² (16, 20) for indigenous South Asian populations. For men, WC cut-points were 90 cm (85, 95) for migrant South Asian, and 87 cm (82, 91) for indigenous South Asian populations. For women, WC cut-points were 77 cm (71, 82) for migrant South Asian, and 54 cm (20, 63) for indigenous South Asian populations. Cut-points based on 2-hour glucose were lower than these.

Conclusions

These findings strengthen evidence that health interventions are required at a lower BMI and WC for South Asian individuals. Based on our data and the existing literature, we suggest an obesity threshold of 25 kg/m² for South Asian individuals, and a very high WC threshold of 90 cm for South Asian men and 77 cm for South Asian women. Further work is required to determine whether lower cut-points are required for indigenous, than migrant, South Asians.

Inadequacies of current approaches to prediabetes and diabetes prevention

In view of the global shift from communicable to chronic, non-communicable diseases including obesity, prediabetes, and type 2 diabetes mellitus, the increasing prevalence of the latter creates a considerable challenge to the clinician and public health infrastructure. Despite the substantial research efforts in the last 10-15 years highlighting the considerable benefit of lifestyle modification in thwarting the insidious progression to diabetes and its complications, many individuals will ineluctably progress even when initially responsive. Furthermore, the vast majority of individuals with prediabetes remain undiagnosed and untreated. Therefore, the responsibilities of the medical and public health communities involve identifying new methods for screening and identifying those at risk as well as refining therapeutic approaches availing as many high-risk individuals as possible to novel treatment modalities.

Progression rates from HbA1c 6.0-6.4% and other prediabetes definitions to type 2 diabetes: a meta-analysis

AIMS/HYPOTHESIS

Precise estimates of progression rates from 'prediabetes' to type 2 diabetes are needed to optimise prevention strategies for high-risk individuals. There is acceptance of prediabetes defined by impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), but there is some controversy surrounding HbA1c-defined prediabetes ranges, with some favouring 6.0-6.4% (42-46 mmol/mol). Comparing progression rates between groups might aid this issue, thus we aimed to accurately estimate progression rates to diabetes from different prediabetes categories.

METHODS

Meta-analysis of prospective observational studies in which participants had prediabetes at baseline (ADA-defined IFG [5.6-6.9 mmol/l], WHO-defined IFG [6.1-6.9 mmol/l], IGT (7.8-11.0 mmol/l) or raised HbA1c [6.0-6.4%/42-46 mmol/mol]) and were followed up for incident diabetes. Incidence rates were combined using Bayesian random effects models.

RESULTS

Overall, 70 studies met the inclusion criteria. In the six studies that used raised HbA1c, the pooled incidence rate (95% credible interval) of diabetes was 35.6 (15.1, 83.0) per 1,000 person-years. This rate was most similar to that for ADA-defined IFG (11 studies; 35.5 [26.6, 48.0]) and was non-significantly lower than WHO-defined IFG (34 studies; 47.4 [37.4, 59.8]), IGT (46 studies, 45.5 [37.8, 54.5]) and IFG plus IGT (15 studies, 70.4 [53.8, 89.7]). Similar results were seen when the data were analysed by the criteria used to diagnose diabetes.

CONCLUSIONS/INTERPRETATION

This study provides evidence that progression rates differ by prediabetes definition, which has implications for the planning and implementation of diabetes prevention programmes. HbA1c 6.0-6.4% might identify people at a lower diabetes risk than other prediabetes definitions, but further research is needed.

1-hour venous plasma glucose and incident prediabetes and diabetes in Asian indians

BACKGROUND

This study evaluated 1-h plasma glucose (1HrPG) levels during an oral glucose tolerance test (OGTT) in predicting progression to diabetes and prediabetes among individuals with normal glucose tolerance (NGT).

SUBJECTS AND METHODS

After analyzing the electronic records of 32,809 subjects who had undergone an OGTT, we identified 1,179 subjects who had NGT at baseline, defined as fasting plasma glucose (FPG) of < 100 mg/dL and 2-h plasma glucose (2HrPG) of < 140 mg/dL, who had at least one follow-up OGTT. Receiver operating characteristic curves were constructed to derive the optimal 1HrPG values, which were associated with the development of diabetes (FPG of ≥ 126 mg/dL or 2HrPG of ≥ 200 mg/dL) or prediabetes (FPG ≥ 100 to <1 26 mg/dL or 2HrPG of ≥ 140 to < 200 mg/dL) at follow-up in these NGT subjects.

RESULTS

On follow-up, 148 (12.6%) subjects developed diabetes, and 392 (33.2%) developed prediabetes. In those with 1HrPG values ≥ 155 mg/dL, 19.5% converted to diabetes compared with 10% among those with 1HrPG of ≥143 to < 155 mg/dL and 6.6% in those with 1HrPG < 143 mg/dL. Comparative figures for conversion to prediabetes were 52.2% (1HrPG values ≥ 155 mg/dL), 39.3% (1HrPG ≥ 143 to <155 mg/dL), and 26.0% (1HrPG < 143 mg/dL). The time to development of diabetes (mean ± SE) was also significantly shorter among those with 1HrPG values of ≥ 155 mg/dL (9.0±0.3 years) compared with those with 1HrPG ≥ 143 to < 155 mg/dL (10.6 ± 0.5 years) and 1HrPG < 143 mg/dL (11.6 ± 0.2 years).

CONCLUSIONS

Among NGT subjects with elevated 1HrPG values during an OGTT, progression to diabetes and prediabetes is greater, and the rate of progression is also faster.

Hemoglobin A1c testing is associated with improved pancreas utilization for transplant

CONTEXT

Aging, higher prevalence of diabetes, worsening obesity, and hyperglycemia among potential donors increase the likelihood that pancreata will be declined by transplant centers. Hemoglobin A1c testing, also known as glycated hemoglobin testing, identifies a donor's average blood glucose concentration for the preceding 2 to 3 months and is the standard test for identifying prolonged periods of hyperglycemia.

OBJECTIVE

To compare pancreas utilization rates before and after implementation of hemoglobin A1c testing.

DESIGN

A retrospective study of data from the New York Organ Donor Network was conducted. Potential donors were defined as standard criteria donors who had no history of diabetes and were not seropositive for hepatitis B or C. Criteria for "ideal" potential pancreas donors were based on age, body mass index, lipase level, and terminal creatinine level. Potential donors who did not meet the criteria for ideal donors were considered "expanded" potential pancreas donors. Pancreas utilization rate was defined as the number of pancreata transplanted divided by the number of potential pancreas donors.

RESULTS

Of 779 standard criteria donors, 691 (89%) were potential pancreas donors: 251 ideal (36%) and 440 expanded (64%) donors. In 2005 and 2006, before hemoglobin A1c testing, pancreas utilization rates were 21% and 18%, respectively. In 2008, 2009, and 2010, after hemoglobin A1c testing was incorporated, utilization rates were 27%, 28%, and 32%, respectively. Utilization of ideal donors increased from 33% to 51% (P= .003), and utilization of expanded donors increased from 11% to 17% (P= .05). Pancreas utilization increased 51.0%, and pancreas discards decreased 50.8% with the implementation of hemoglobin A1c testing.

CONCLUSION

Hemoglobin A1c testing may increase utilization of ideal and expanded criteria pancreata.

Diagnostic performance of using one- or two-HbA1c cut-point strategies to detect undiagnosed type 2 diabetes and impaired glucose regulation within a multi-ethnic population

INTRODUCTION

We compared test performance and cost per case for strategies detecting diabetes on the oral glucose tolerance test (OGTT) using either (a) glycated haemoglobin (HbA1c) ≥ 6.5% (48 mmol/mol) or (b) two HbA1c thresholds where the first cut-point 'rules out' and the second 'rules in' diabetes. HbA1c values in between the thresholds require confirmatory glucose testing for diagnosis.

MATERIALS AND METHODS

We conducted an analysis of adults aged 40-75 years from the Leicester Ethnic Atherosclerosis and Diabetes Risk (LEADER) cohort (Leicester, UK), from 2002 to 2008, who underwent oral glucose tolerance testing (OGTT) and HbA1c testing.

RESULTS

From 8696 individuals (mean age 57.3 years, 73% white Europeans (WE) and 27% South Asians (SA)), HbA1c ≥ 6.5% produced sensitivity of 62.1% for detecting diabetes in WE and 78.9% in SA. Using two selected thresholds, HbA1c ≤ 5.8% (rule-in, 40 mmol/mol) and HbA1c ≥ 6.8% (rule-out, 51 mmol/mol) produced high sensitivity/specificity (> 91.0%) for detecting diabetes, however, 28.8% of the cohort with HbA1c 5.9%-6.7% required a subsequent glucose test. The two cut-point threshold produced a lower cost per case of diabetes detected in WE, compared to HbA1c ≥ 6.5% of £38.53 (1.89 to 86.81) per case, but was more expensive in SA by £84.50 (69.72 to 100.92) per case. Using a risk score to determine HbA1c testing, the same costs per case became £63.33 (23.33 to 113.26) in WE and £69.21 (55.60 to 82.41) in SA.

CONCLUSION

Using a two-threshold strategy may have some benefits over a single cut-point; however, 28.8% of individuals required two blood tests.

Accuracy of glycated haemoglobin in screening for pre-diabetes in Asian Indians--a community survey: the Chandigarh Urban Diabetes Study (CUDS)

AIM

To compare American Diabetes Association and International Expert Committee recommended cut-off values of HbA(1c) for detecting the presence of pre-diabetes against plasma glucose values obtained from oral glucose tolerance tests in Asian Indians.

METHODS

A cross-sectional randomly sampled population survey involving 2368 adults, aged ≥ 20 years. HbA(1c) was measured on a Bio-Rad 10 system in 1972 subjects.

RESULTS

Of the 1972 subjects studied, 329 were detected to have pre-diabetes based on isolated impaired fasting glucose in 125 subjects (6.3%), isolated impaired glucose tolerance in 141 subjects (7.1%) and the presence of both in 63 subjects (3.2%). The HbA(1c) cut-off of 34 mmol/mol (5.7%), as recommended by the American Diabetes Association for detecting the presence of pre-diabetes, showed sensitivity of 62%, specificity 77%, with a positive predictive value of 34.7%, a negative predictive value of 89.5% and accuracy of 67.8%; whereas the HbA(1c) cut-off recommended by the International Expert Committee of 42 mmol/mol (6%) had a sensitivity of 36%, specificity of 90%, positive predictive value of 42.7%, negative predictive of 85.4% and an accuracy of 77%. However, both these HbA(1c) cut-offs underdiagnosed the presence of pre-diabetes in 38 and 64% of these subjects, respectively.

CONCLUSIONS

The American Diabetes Association and the International Expert Committee recommended HbA(1c) cut-off values and oral glucose tolerance tests identify different pre-diabetes cohorts. Long-term prospective studies are required to define the usefulness of one over the other.

Hemoglobin A1c levels and aortic arterial stiffness: the Cardiometabolic Risk in Chinese (CRC) study

OBJECTIVE

The American Diabetes Association (ADA) recently published new clinical guidelines in which hemoglobin A1c (HbA1c) was recommended as a diagnostic test for diabetes. The present study was to investigate the association between HbA1c and cardiovascular risk, and compare the associations with fasting glucose and 2-hour oral glucose tolerance test (2 h OGTT).

RESEARCH DESIGN AND METHODS

The study samples are from a community-based health examination survey in central China. Carotid-to-femoral pulse wave velocity (cfPWV) and HbA1c were measured in 5,098 men and women.

RESULTS

After adjustment for age, sex, and BMI, the levels of HbA1c were significantly associated with an increasing trend of cfPWV in a dose-dependent fashion (P for trend <0.0001). The associations remained significant after further adjustment for blood pressure, heart rate, and lipids (P = 0.004), and the difference in cfPWV between the highest and the lowest quintiles of HbA1c was 0.31 m/s. Fasting glucose and 2 h OGTT were not associated with cfPWV in the multivariate analyses. HbA1c showed additive effects with fasting glucose or 2 h OGTT on cfPWV. In addition, age and blood pressure significantly modified the associations between HbA1c and cfPWV (P for interactions <0.0001 for age; and  = 0.019 for blood pressure). The associations were stronger in subjects who were older (≥60 y; P for trend = 0.004) and had higher blood pressure (≥120 [systolic blood pressure]/80 mmHg [diastolic blood pressure]; P for trend = 0.028) than those who were younger and had lower blood pressure (P for trend >0.05).

CONCLUSIONS

HbA1c was related to high cfPWV, independent of conventional cardiovascular risk factors. Senior age and high blood pressure might amplify the adverse effects of HbA1c on cardiovascular risk.

A minimally invasive system for glucose area under the curve measurement using interstitial fluid extraction technology: evaluation of the accuracy and usefulness with oral glucose tolerance tests in subjects with and without diabetes

BACKGROUND

Recent studies have highlighted the importance of managing postprandial hyperglycemia, but adequate monitoring of postprandial glucose remains difficult because of wide variations in levels. We have therefore developed a minimally invasive system to monitor postprandial glucose area under the curve (AUC). This system involves no blood sampling and uses interstitial fluid glucose (IG) AUC (IG-AUC) as a surrogate marker of postprandial glucose. This study aimed to evaluate the usefulness of this system by comparing data with the findings of oral glucose tolerance tests (OGTTs) in subjects with and without diabetes.

SUBJECTS AND METHODS

The glucose AUC monitoring system was validated by OGTTs in 37 subjects with and 10 subjects without diabetes. A plastic microneedle array was stamped on the forearm to extract IG. A hydrogel patch was then placed on the pretreated area to accumulate IG. Glucose and sodium ion concentrations in the hydrogel were measured to calculate IG-AUC at 2-h postload glucose. Plasma glucose (PG) levels were measured every 30 min to calculate reference PG-AUC.

RESULTS

IG-AUC correlated strongly with reference PG-AUC (r=0.93) over a wide range. The level of correlation between IG-AUC and maximum PG level was also high (r=0.86). The painless nature of the technique was confirmed by the response of patients to questionnaires.

CONCLUSIONS

The glucose AUC monitoring system using IG provided good estimates of reference PG-AUC and maximum PG level during OGTTs in subjects with and without diabetes. This system provides easy-to-use monitoring of glucose AUC, which is a good indicator of postprandial glucose.

Diabetes mellitus is associated with shortened activated partial thromboplastin time and increased fibrinogen values

OBJECTIVE

This study was designed to examine the relationship between shortened activated partial thromboplastin time (APTT) and increased fibrinogen values with diabetes mellitus.

METHODS

APTT, prothrombin time (PT), fibrinogen, fasting plasma glucose (FPG) and glycosylated hemoglobin A1c (HbA1c) levels were measured in 1,300 patients. Patients were divided into three groups according to their HbA1c and FPG levels.

RESULTS

When participants were grouped according to their HbA1c levels, we found significantly shorter APTT values (26.9±5.6 s) and increased fibrinogen levels (3.1, 1.9-6.3 g/L) in the diabetes group when compared with the other two groups. When participants were grouped according to their FPG levels, we found significantly shorter APTT values (26.9±6.2 s) and increased fibrinogen levels (3.1, 1.8-6.2 g/L) in the diabetes group when compared with the euglycemic group.

CONCLUSIONS

Shorter APTT and increased fibrinogen levels might be useful hemostatic markers in patients with diabetes and in patients at high risk for diabetes.