Glucose-independent ethnic differences in HbA1c in people without known diabetes

Assessing blood sugar measures for predicting new-onset diabetes and cardiovascular disease in community-dwelling adults

PURPOSE

Diabetes mellitus (DM) is a global health concern linked to various complications, including cardiovascular disease (CVD). However, long-term follow-up studies on the risk of DM and CVD using different blood glucose assessment methods in the general Korean population are lacking. This study aimed to assess the predictive abilities of fasting plasma glucose (FPG), 2-h oral glucose tolerance test (OGTT), and glycosylated hemoglobin (HbA1c) for new-onset DM and high CVD risk in a middle-aged and older Korean population.

METHODS

This study used data from the Korean Genome and Epidemiology Study, a population-based prospective cohort. Blood sugar measures (FPG, OGTT, and HbA1c) were examined. The primary endpoint was the development of new-onset DM, and CVD risk was evaluated using the Framingham risk score. The predictive abilities for new-onset DM based on glycemic values were evaluated using Harrell's Concordance index and 95% confidence intervals.

RESULTS

Among the 10,030 participants, data of 6813 participants without DM at baseline were analyzed. The study revealed that OGTT outperformed FPG and HbA1c in predicting new-onset DM. The combination of FPG and HbA1c did not significantly enhance predictions for DM compared with OGTT alone. OGTT also outperformed FPG and HbA1c in predicting high CVD risk, and this difference remained significant even after adjusting for additional confounders.

CONCLUSION

OGTT has superior predictive capabilities in identifying new-onset DM and high CVD risk in the Korean population. This suggests that relying solely on individual blood sugar measures may be insufficient for assessing DM and CVD risks.

Prediabetes and Cardiometabolic Risk: The Need for Improved Diagnostic Strategies and Treatment to Prevent Diabetes and Cardiovascular Disease

The progression from prediabetes to type-2 diabetes depends on multiple pathophysiological, clinical, and epidemiological factors that generally overlap. Both insulin resistance and decreased insulin secretion are considered to be the main causes. The diagnosis and approach to the prediabetic patient are heterogeneous. There is no agreement on the diagnostic criteria to identify prediabetic subjects or the approach to those with insufficient responses to treatment, with respect to regression to normal glycemic values or the prevention of complications. The stratification of prediabetic patients, considering the indicators of impaired fasting glucose, impaired glucose tolerance, or HbA1c, can help to identify the sub-phenotypes of subjects at risk for T2DM. However, considering other associated risk factors, such as impaired lipid profiles, or risk scores, such as the Finnish Diabetes Risk Score, may improve classification. Nevertheless, we still do not have enough information regarding cardiovascular risk reduction. The sub-phenotyping of subjects with prediabetes may provide an opportunity to improve the screening and management of cardiometabolic risk in subjects with prediabetes.

Ethnicity, Age, and Gender Differences in Glycated Hemoglobin (HbA1c) Levels among Adults in Northern and Eastern Sudan: A Community-Based Cross-Sectional Study

BACKGROUND

The level of association between glycated hemoglobin (HbA1c) level and ethnicity, age, and gender is not yet settled. This study aimed to investigate the association between ethnicity, age, and gender and HbA1c level among adults who were known not to have diabetes mellitus in northern and eastern Sudan.

METHODS

A comparative community-based cross-sectional study was conducted. Sociodemographic and clinical characteristics data were collected. HbA1c levels were measured, and multiple linear regression analysis was performed.

RESULTS

A total of 898 adults (363 in northern Sudan and 535 in eastern Sudan) were included; 349 (38.9%) were males. The HbA1c level was significantly higher in eastern Sudan, and there was no significant difference in HbA1c levels between genders. In multiple linear regression, for adults with HbA1c <6.5%, ethnicity and BMI were associated with HbA1c, but age and gender were not associated with HbA1c. In northern Sudan, age was positively associated with HbA1c, and there was no association between gender, BMI, and HbA1c in adults with HbA1c <6.5%. In eastern Sudan, BMI was positively associated with HbA1c, and there was no significant association between age and gender and HbA1c level in adults with HbA1c <6.5%.

CONCLUSION

HbA1c levels are influenced by ethnicity and age but not by gender.

Early postpartum HbA1c after hyperglycemia first detected in pregnancy-Imperfect but not without value

BACKGROUND

South African women of childbearing age are disproportionally affected by obesity and at significant risk of Type 2 Diabetes Mellitus (T2DM). Unless pregnant, they do not readily undergo screening for T2DM. With a local focus on improved antenatal care, hyperglycemia is often first detected in pregnancy (HFDP). This may erroneously be attributed to Gestational Diabetes Mellitus (GDM) in all without considering T2DM. Glucose evaluation following pregnancy is essential for early detection and management of women with T2DM in whom persistent hyperglycemia is to be expected. Conventional testing with an oral glucose tolerance test (OGTT) is cumbersome, prompting investigation for alternate solutions.

AIM

To compare the diagnostic performance of HbA1c to the current gold standard OGTT in women with HFDP 4-12 weeks post-delivery.

METHODS

Glucose homeostasis was assessed with OGTT and HbA1c in 167 women with HFDP, 4-12 weeks after delivery. Glucose status was based on American Diabetes Association criteria.

RESULTS

Glucose homeostasis was assessed at 10 weeks (IQR 7-12) after delivery. Of the 167 participants, 52 (31%) had hyperglycemia, which was comprised of 34 (20%) prediabetes and 18 (11%) T2DM. Twelve women in the prediabetes subgroup had diagnostic fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG), but in two-thirds of the patients (22/34) only one time point proved diagnostic. The FPGs and the 2hPGs of six women with HbA1c-based T2DM were both within the prediabetes diagnostic range. According to the HbA1c measurements, 85% of 52 participants with gold standard OGTT defined hyperglycemia (prediabetes and T2DM) as well as 15 of 18 women with postpartum persistent T2DM were correctly classified. According to FPG, 15 women with persistent hyperglycemia would have been missed (11 with prediabetes and four with T2DM; 29%). When compared to an OGTT, a single HbA1c of 6.5% (48mmol/mol) postpartum demonstrated a sensitivity of 83% and specificity of 97% for the identification of T2DM.

CONCLUSION

HbA1c may improve access to postpartum testing in overburdened clinical settings where the required standards of OGTT cannot be guaranteed. HbA1c is a valuable test to detect women who will benefit most from early intervention but cannot unequivocally replace OGTT.

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

OBJECTIVES

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

DESIGN

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

DATA SOURCES

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

ELIGIBILITY CRITERIA

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

DATA EXTRACTION

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

RESULTS

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

CONCLUSIONS

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

The diagnostic accuracy of HbA1c , compared to the oral glucose tolerance test, for screening for type 2 diabetes mellitus in Africa-A systematic review and meta-analysis

OBJECTIVE

To assess the diagnostic accuracy of glycated haemoglobin A_1c (HbA_1c ), compared to fasting plasma glucose (FPG) and the oral glucose tolerance test (OGTT), in screening for type 2 diabetes (T2D) in Africa.

METHODS

We systematically searched databases for studies that compared the HbA_1c to either the OGTT, or the FPG for T2D diagnosis were included. The QUADAS 2 tool was used for assessing the quality of included studies. We used the split component synthesis (SCS) method for the meta-analysis of diagnostic accuracy studies to pool the studies for meta-analysis of sensitivity and specificity, primarily at the HbA_1c ≥48 mmol/mol (6.5%) cut-off and at other cut-offs. We assessed heterogeneity using the I²  statistic and publication bias using Doi plots.

RESULTS

Eleven studies, from seven African countries, with 12,925 participants, were included. Against the OGTT, HbA_1c ≥48 mmol/mol (6.5%) had a pooled sensitivity of 57.7% (95% confidence interval [CI] 43.4-70.9) and specificity of 92.3% (95% CI 83.9-96.5). Against the FPG, HbA_1c ≥48 mmol/mol (6.5%) had a pooled sensitivity of 64.5% (95% CI 50.5-76.4) and specificity of 94.3% (95% CI 87.9-97.5). The highest sensitivity for HbA_1c , against the OGTT, was at the 42 mmol/mol (6.0%) cut-off.

CONCLUSION

In Africa, the HbA_1c ≥48 mmol/mol (6.5%) cut-off may miss almost half of the individuals with T2D based on blood glucose measures.

Association of glycated hemoglobin A1c levels with cardiovascular outcomes in the general population: results from the BiomarCaRE (Biomarker for Cardiovascular Risk Assessment in Europe) consortium

BACKGROUND

Biomarkers may contribute to improved cardiovascular risk estimation. Glycated hemoglobin A1c (HbA1c) is used to monitor the quality of diabetes treatment. Its strength of association with cardiovascular outcomes in the general population remains uncertain. This study aims to assess the association of HbA1c with cardiovascular outcomes in the general population.

METHODS

Data from six prospective population-based cohort studies across Europe comprising 36,180 participants were analyzed. HbA1c was evaluated in conjunction with classical cardiovascular risk factors (CVRFs) for association with cardiovascular mortality, cardiovascular disease (CVD) incidence, and overall mortality in subjects without diabetes (N = 32,496) and with diabetes (N = 3684).

RESULTS

Kaplan-Meier curves showed higher event rates with increasing HbA1c levels (log-rank-test: p < 0.001). Cox regression analysis revealed significant associations between HbA1c (in mmol/mol) in the total study population and the examined outcomes. Thus, a hazard ratio (HR) of 1.16 (95% confidence interval (CI) 1.02-1.31, p = 0.02) for cardiovascular mortality, 1.13 (95% CI 1.03-1.24, p = 0.01) for CVD incidence, and 1.09 (95% CI 1.02-1.17, p = 0.01) for overall mortality was observed per 10 mmol/mol increase in HbA1c. The association with CVD incidence and overall mortality was also observed in study participants without diabetes with increased HbA1c levels (HR 1.12; 95% CI 1.01-1.25, p = 0.04) and HR 1.10; 95% CI 1.01-1.20, p = 0.02) respectively. HbA1c cut-off values of 39.9 mmol/mol (5.8%), 36.6 mmol/mol (5.5%), and 38.8 mmol/mol (5.7%) for cardiovascular mortality, CVD incidence, and overall mortality, showed also an increased risk.

CONCLUSIONS

HbA1c is independently associated with cardiovascular mortality, overall mortality and cardiovascular disease in the general European population. A mostly monotonically increasing relationship was observed between HbA1c levels and outcomes. Elevated HbA1c levels were associated with cardiovascular disease incidence and overall mortality in participants without diabetes underlining the importance of HbA1c levels in the overall population.

Elevated Serum TNF-α Is Related to Obesity in Type 2 Diabetes Mellitus and Is Associated with Glycemic Control and Insulin Resistance

BACKGROUND

Diabetes and obesity are very common associated metabolic disorders that are linked to chronic inflammation. Leptin is one of the important adipokines released from adipocytes, and its level increases with increasing body mass index (BMI). Tumor necrosis factor alpha (TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF-Methodology. This is a cross-sectional study involving 63 healthy volunteers and 65 patients with T2DM. Body composition was measured, and fasting venous blood samples were analyzed for blood glucose, glycosylated hemoglobin (HbA1c), basal insulin, leptin, and TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF.

RESULTS

Our study showed a significantly higher level of TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF-p=0.008). In obese diabetic patients, the serum level of TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF-p=0.008). In obese diabetic patients, the serum level of TNF-p=0.008). In obese diabetic patients, the serum level of TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF-r = 0.361, p=0.008). In obese diabetic patients, the serum level of TNF-r = 0.361, p=0.008). In obese diabetic patients, the serum level of TNF.

CONCLUSION

TNF-α is associated with concurrent obesity and T2DM and correlates with HbA1c. This suggests that TNF-α needs further investigation to explore if it has a role in monitoring the effectiveness of management in individuals with obesity and T2DM.α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF-α) is a cytokine that is released by adipocytes and inflammatory cells in response to chronic inflammation. Type 2 diabetes mellitus (T2DM) is believed to be associated with low-grade chronic inflammation. The current study aims to investigate the involvement of leptin and TNF.

Association between gain in adiposity and diabetic kidney disease worsening in type 2 diabetes is mediated by deteriorating glycaemic control: A 3-year follow-up analysis

AIMS

Increased adiposity confers elevated risk for diabetic kidney disease (DKD) progression in type 2 diabetes mellitus (T2DM). This 3-year prospective study examined whether worsening of metabolic control e.g. development of uncontrolled diabetes mediated the relationship between increased adiposity and DKD deterioration.

METHODS

T2DM subjects who had adequately controlled diabetes (HbA1c < 8%) at initial recruitment were analysed (N = 853). HbA1c ≥ 8% at follow-up was classified as development of uncontrolled T2DM. Absolute changes in body weight (ΔWeight), body mass index (ΔBMI), and body fat mass (ΔBFM) were calculated by subtracting baseline from follow-up values. DKD deterioration (outcome) was defined as an increase in the composite ranking of relative risk by glomerular filtration rate and albuminuria levels (Kidney Disease: Improving Global Outcomes 2009).

RESULTS

Subjects with deteriorated DKD displayed lower reduction in body composition at follow-up than those who remained stable or/improved (all P < 0.05). In separate regression models, ΔWeight (risk ratio (RR):1.04, 95% CI:1.01-1.06), ΔBMI (RR:1.07, 95% CI:1.01-1.13), and ΔBFM (RR:1.03, 95% CI:1.01-1.06) were independently associated with worsened DKD. The associations were attenuated after accounting for the loss of glycaemic control. Binary mediation analysis revealed that the development of uncontrolled diabetes explained 41.7%, 45.4% and 39.7%, respectively, of the effects of ΔWeight, ΔBMI and ΔBFM on the outcome.

CONCLUSIONS

Among T2DM individuals who had adequately-controlled T2DM at initial recruitment, the relationship between gain in adiposity and DKD deterioration is mediated by the development of poor glycaemic control over time. Therefore, preventing worsening adiposity and hyperglycaemia is pivotal to impede DKD progression.

The association between anthropometric measures and glycated haemoglobin (HbA1c) is different in Russian, Somali and Kurdish origin migrants compared with the general population in Finland: a cross-sectional population-based study

BACKGROUND

Persons of African and Middle-Eastern origin living in European countries have a high prevalence of type 2 diabetes, accompanied by high prevalence of obesity among women but not always among men. The aim of this study was to examine whether there are differences in the association between anthropometric measures and glucose levels measured with glycated haemoglobin and fasting blood glucose among persons of migrant origin in Finland.

METHODS

Cross-sectional population-based data of the 30-64 year-old participants in the health examination of the Migrant Health and Wellbeing Study was used, selecting persons without diabetes (Russian origin n = 293, Somali origin n = 184, Kurdish origin n = 275). The reference group were non-diabetic participants in the Health 2011 Survey (n = 653), representative of the general Finnish population. Anthropometric measures included body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR) and waist-to-hip ratio (WHR, available for Maamu Study participants only).

RESULTS

Depending on whether continuous or categorical anthropometric measures were used, age, sex and anthropometrics explained 13-18% of variation in HbA1c among persons of Russian origin, 5-10% among persons of Somali origin, 1-3% among persons of Kurdish origin and 11-13% among the general population. Also depending on whether continuous or categorical anthropometric measures were used, age, sex and anthropometrics explained 13-19% of variation in fasting blood glucose among persons of Russian origin, 15-20% among persons of Somali origin, 13-17% among persons of Kurdish origin and 16-17% among the general population. With exception for BMI, strength of the association between continuous anthropometric measures and HbA1c was significantly lower among persons of Kurdish origin compared with the general Finnish population (p = 0.044 for WC and p = 0.040 for WHtR).

CONCLUSIONS

A low degree of association between anthropometric measures and HbA1c was observed among persons of Kurdish origin. Findings of this study suggest caution is warranted when using HbA1c as a screening tool for glucose impairment among persons without diabetes in populations of diverse origin.

Led Astray by Hemoglobin A1c: A Case of Misdiagnosis of Diabetes by Falsely Elevated Hemoglobin A1c

Hemoglobin A1c (A1c) is used frequently to diagnose and treat diabetes mellitus. Therefore, it is important be aware of factors that may interfere with the accuracy of A1c measurements. This is a case of a rare hemoglobin variant that falsely elevated a nondiabetic patient’s A1c level and led to a misdiagnosis of diabetes. A 67-year-old male presented to endocrine clinic for further management after he was diagnosed with diabetes based on an elevated A1c of 10.7%, which is approximately equivalent to an average blood glucose of 260 mg/dL. Multiple repeat A1c levels remained >10%, but his home fasting and random glucose monitoring ranged from 92 to 130 mg/dL. Hemoglobin electrophoresis and subsequent genetic analysis diagnosed the patient with hemoglobin Wayne, a rare hemoglobin variant. This variant falsely elevates A1c levels when A1c is measured using cation-exchange high-performance liquid chromatography. When the boronate affinity method was applied instead, the patient’s A1c level was actually 4.7%. Though hemoglobin Wayne is clinically silent, this patient was erroneously diagnosed with diabetes and started on an antiglycemic medication. Due to this misdiagnosis, the patient was at risk of escalation in his “diabetes management” and hypoglycemia. Therefore, it is important that providers are aware of factors that may result in hemoglobin A1c inaccuracy including hemoglobin variants.

Diabetes case finding in the emergency department, using HbA1c: an opportunity to improve diabetes detection, prevention, and care

OBJECTIVE

We assessed the efficacy of routine glycated hemoglobin (HbA1c) testing to detect undiagnosed diabetes and prediabetes in an urban Australian public hospital emergency department (ED) located in an area of high diabetes prevalence.

METHODS

Over 6 weeks, all patients undergoing blood sampling in the ED had their random blood glucose measured. If ≥5.5 mmol/L (99 mg/dL), HbA1c was measured on the same sample. HbA1c levels ≥6.5% (48 mmol/mol) and 5.7-6.4% (39-46 mmol/mol) were diagnostic of diabetes and prediabetes, respectively. Hospital records were reviewed to identify patients with previously diagnosed diabetes.

RESULTS

Among 4580 presentations, 2652 had blood sampled of which 1267 samples had HbA1c measured. Of these, 487 (38.4%) had diabetes (either HbA1c≥6.5% or a prior diagnosis), and a further 347 (27.4%) had prediabetes. Among those with diabetes, 32.2% were previously undiagnosed.

CONCLUSIONS

Routine HbA1c testing in the ED identifies a large number of people with undiagnosed diabetes and prediabetes, and provides an opportunity to improve their care.

Effects of diabetes definition on global surveillance of diabetes prevalence and diagnosis: a pooled analysis of 96 population-based studies with 331,288 participants

BACKGROUND

Diabetes has been defined on the basis of different biomarkers, including fasting plasma glucose (FPG), 2-h plasma glucose in an oral glucose tolerance test (2hOGTT), and HbA1c. We assessed the effect of different diagnostic definitions on both the population prevalence of diabetes and the classification of previously undiagnosed individuals as having diabetes versus not having diabetes in a pooled analysis of data from population-based health examination surveys in different regions.

METHODS

We used data from 96 population-based health examination surveys that had measured at least two of the biomarkers used for defining diabetes. Diabetes was defined using HbA1c (HbA1c ≥6·5% or history of diabetes diagnosis or using insulin or oral hypoglycaemic drugs) compared with either FPG only or FPG-or-2hOGTT definitions (FPG ≥7·0 mmol/L or 2hOGTT ≥11·1 mmol/L or history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated diabetes prevalence, taking into account complex survey design and survey sample weights. We compared the prevalences of diabetes using different definitions graphically and by regression analyses. We calculated sensitivity and specificity of diabetes diagnosis based on HbA1c compared with diagnosis based on glucose among previously undiagnosed individuals (ie, excluding those with history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated sensitivity and specificity in each survey, and then pooled results using a random-effects model. We assessed the sources of heterogeneity of sensitivity by meta-regressions for study characteristics selected a priori.

FINDINGS

Population prevalence of diabetes based on FPG-or-2hOGTT was correlated with prevalence based on FPG alone (r=0·98), but was higher by 2-6 percentage points at different prevalence levels. Prevalence based on HbA1c was lower than prevalence based on FPG in 42·8% of age-sex-survey groups and higher in another 41·6%; in the other 15·6%, the two definitions provided similar prevalence estimates. The variation across studies in the relation between glucose-based and HbA1c-based prevalences was partly related to participants' age, followed by natural logarithm of per person gross domestic product, the year of survey, mean BMI, and whether the survey population was national, subnational, or from specific communities. Diabetes defined as HbA1c 6·5% or more had a pooled sensitivity of 52·8% (95% CI 51·3-54·3%) and a pooled specificity of 99·74% (99·71-99·78%) compared with FPG 7·0 mmol/L or more for diagnosing previously undiagnosed participants; sensitivity compared with diabetes defined based on FPG-or-2hOGTT was 30·5% (28·7-32·3%). None of the preselected study-level characteristics explained the heterogeneity in the sensitivity of HbA1c versus FPG.

INTERPRETATION

Different biomarkers and definitions for diabetes can provide different estimates of population prevalence of diabetes, and differentially identify people without previous diagnosis as having diabetes. Using an HbA1c-based definition alone in health surveys will not identify a substantial proportion of previously undiagnosed people who would be considered as having diabetes using a glucose-based test.

FUNDING

Wellcome Trust, US National Institutes of Health.

Impact of ethnicity on progress of glycaemic control in 131,935 newly diagnosed patients with type 2 diabetes: a nationwide observational study from the Swedish National Diabetes Register

OBJECTIVES

Studies on ethnic disparities in glycaemic control have been contradictory, and compromised by excessively broad categories of ethnicity and inadequate adjustment for socioeconomic differences. We aimed to study the effect of ethnicity on glycaemic control in a large cohort of patients with type 2 diabetes.

SETTING

We used nationwide data (mainly from primary care) from the Swedish National Diabetes Register (2002-2011) to identify patients with newly diagnosed (within 12 months) type 2 diabetes.

PARTICIPANTS

We included 131,935 patients (with 713,495 appointments), representing 10 ethnic groups, who were followed up to 10 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Progress of glycated haemoglobin (HbA1c) for up to 10 years was examined. Mixed models were used to correlate ethnicity with HbA1c (mmol/mol). The effect of glycaemic disparities was examined by assessing the risk of developing albuminuria. The impact of ethnicity was compared to that of income, education and physical activity.

RESULTS

Immigrants, particularly those of non-Western origin, received glucose-lowering therapy earlier, had 30% more appointments but displayed poorer glycaemic control (2-5 mmol/mol higher HbA1c than native Swedes). Probability of therapy failure was 28-111% higher for non-Western groups than for native Swedes. High-income Western groups remained below the target-level of HbA1c for 4-5 years, whereas non-Western populations never reached the target level. These disparities translated into 51-92% higher risk of developing albuminuria. The impact of ethnicity was greater than the effect of income and education, and equal to the effect of physical activity.

CONCLUSIONS

Despite earlier pharmacological treatment and more frequent appointments, immigrants of non-Western origin display poorer glycaemic control and this is mirrored in a higher risk of developing albuminuria.

Use of an oral stable isotope label to confirm variation in red blood cell mean age that influences HbA1c interpretation

HbA1c is commonly used to monitor glycemic control. However, there is growing evidence that the relationship between HbA1c and mean blood glucose (MBG) is influenced by variation in red blood cell (RBC) lifespan in hematologically normal individuals. Correction of HbA1c for mean RBC age (MRBC ) requires a noninvasive, accurate, and affordable method to measure RBC survival. In this study, we evaluated whether a stable isotope approach would satisfy these requirements. RBC lifespan and MRBC were determined in a group of nine hematologically normal diabetic and nondiabetic subjects using oral (15) N-glycine to label heme in an age cohort of RBC. The MRBC was 58.7 ± 9.1 (2SD) days and RBC lifespan was 106 ± 21 (2SD) days. This degree of variation (±15-20%) is consistent with previous studies using other techniques. In a subset of seven subjects, MRBC determined with the biotin label technique were available from approximately five years prior, and strongly correlated with the stable isotope values (R(2) = 0.79). This study suggests that the MRBC is stable over time but varies substantially among individuals, and supports the importance of its variation in HbA1c interpretation. The characteristics of the stable isotope method support its suitability for studies to directly evaluate the impact of variation in MRBC on the interpretation of HbA1c.

Monitoring HIV-infected Patients with Diabetes: Hemoglobin A1c, Fructosamine, or Glucose?

BACKGROUND

Published studies report inappropriately low hemoglobin A1C (HbA1c) values that underestimate glycemia in HIV patients.

METHODS

We reviewed the charts of all HIV patients with diabetes mellitus (DM) at our clinic. Fifty-nine patients had HbA1c data, of whom 26 patients also had fructosamine data. We compared the most recent HbA1c to finger-stick (FS) glucose averaged over three months, and fructosamine to FS averaged over six weeks. Predicted average glucose (pAG) was calculated as reported by Nathan et al: pAG (mg/dL) = 28.7 × A1C% − 46.7. Data were analyzed using the Statistical Analysis System (SAS) and Kruskal–Wallis test.

RESULTS

HbA1c values underestimated (UE) actual average glucose (aAG) in 19% of these patients and overestimated (OE) aAG in 27%. HbA1c estimated aAG within the established range in only 54% of the patients. There were no statistical differences in the types of HIV medication used in patients with UE, OE, or accurately estimated (AE) glycemia. A Spearman correlation coefficient between HbA1c and aAG was r = 0.53 (P < 0.0001). Correlation between fructosamine and aAG was r = 0.47 (P = 0.016).

CONCLUSIONS

The correlations between HbA1c and aAG and between fructosamine and aAG were weaker than expected, and fructosamine was not more accurate than HbA1c.

Epidemiological ramifications of diagnosing diabetes with HbA1c levels

AIMS

To compare the prevalence of diabetes by history and using the fasting plasma glucose (FPG) criterion alone, the HbA1c criterion alone or either one in those not known to have diabetes.

METHODS

Analysis of NHANES population ≥20years old from 1999 through 2010.

RESULTS

In those diagnosed by laboratory tests, 86% met the FPG criterion and 53% met the HbA1c criterion. The prevalence of diabetes (history or laboratory test) was significantly increased when the FPG criterion was used compared with the HbA1c criterion in the entire (11.5% vs 10.5%, P=0.018) and Caucasian (10.6% vs 9.2%, P=0.022) populations. In contrast, there were no significant differences in the prevalence when only the FPG criterion was used compared with only the HbA1c criterion in Hispanics (12.9% vs 12.1% P=0.386) and African Americans (14.5 vs 14.3%, P=0.960). Using history and either criterion in those not known to have it, diabetes increased by 61% in this 12year period in adults ≥20years old.

CONCLUSIONS

Using the FPG rather than the HbA1c criterion to diagnose diabetes in those without a history significantly increased the total prevalence of diabetes in Caucasians but not in African Americans or Hispanics.

Development of a new risk score for incident type 2 diabetes using updated diagnostic criteria in middle-aged and older chinese

Type 2 diabetes mellitus (T2DM) reaches an epidemic proportion among adults in China. However, no simple score has been created for the prediction of T2DM incidence diagnosed by updated criteria with hemoglobin A1c (HbA1c) ≥6.5% included in Chinese. In a 6-year follow-up cohort in Beijing and Shanghai, China, we recruited a total of 2529 adults aged 50–70 years in 2005 and followed them up in 2011. Fasting plasma glucose (FPG), HbA1c, and C-reactive protein (CRP) were measured and incident diabetes was identified by the recently updated criteria. Of the 1912 participants without T2DM at baseline, 924 were identified as having T2DM at follow-up, and most of them (72.4%) were diagnosed using the HbA1c criterion. Baseline body mass index, FPG, HbA1c, CRP, hypertension, and female gender were all significantly associated with incident T2DM. Based upon these risk factors, a simple score was developed with an estimated area under the receiver operating characteristic curve of 0.714 (95% confidence interval: 0.691, 0.737), which performed better than most of existing risk score models developed for eastern Asian populations. This simple, newly constructed score of six parameters may be useful in predicting T2DM in middle-aged and older Chinese.