Differences in A1C by race and ethnicity among patients with impaired glucose tolerance in the Diabetes Prevention Program

Epidemiology of Dysglycemia in Pregnant Oklahoma American Indian Women

CONTEXT

Minority communities are disproportionately affected by diabetes, and minority women are at an increased risk for glucose intolerance (dysglycemia) during pregnancy.

OBJECTIVES

In pregnant American Indian women, the objectives of the study were to use current criteria to estimate the prevalence of first-trimester (Tr1) dysglycemia and second-trimester (Tr2) incidence of gestational diabetes mellitus (GDM) and to explore new candidate measures and identify associated clinical factors.

DESIGN

This was a prospective cohort study. In Tr1 we performed a 75-g, 2-hour oral glucose tolerance test (OGTT) and glycated hemoglobin (HbA1c) to determine the following: fasting insulin; homeostasis model assessment of insulin resistance; serum 1,5-anhydroglucitol; noninvasive skin autofluorescence (SCOUT). We defined dysglycemia by American Diabetes Association and Endocrine Society criteria and as HbA1c of 5.7% or greater. In Tr2 in an available subset, we performed a repeat OGTT and SCOUT.

PARTICIPANTS

Pregnant American Indian women (n = 244 at Tr1; n = 114 at Tr2) participated in the study.

OUTCOMES

The prevalence of dysglycemia at Tr1 and incidence of GDM at Tr2 were measured.

RESULTS

At Tr1, one woman had overt diabetes; 36 (15%) had impaired glucose tolerance (American Diabetes Association criteria and/or abnormal HbA1c) and 59 (24%) had GDM-Tr1 (Endocrine Society criteria). Overall, 74 (30%) had some form of dysglycemia. Associated factors were body mass index, hypertension, waist/hip circumferences, SCOUT score, fasting insulin, and homeostasis model assessment of insulin resistance. At Tr2, 114 of the Tr1 cohort underwent a repeat OGTT and SCOUT, and 26 (23%) had GDM. GDM-Tr2 was associated with increased SCOUT scores (P = .029) and Tr1 body mass index, waist/hip circumferences, diastolic blood pressure, fasting insulin, and triglyceride levels. Overall, dysglycemia at Tr1 and/or Tr2 affected 38% of the women.

CONCLUSIONS

Dysglycemia at some point during pregnancy was common among American Indian women. It was associated with features of insulin resistance and may confer long-term health risks for mother and child.

Ethnic/racial determinants of glycemic markers in a UK sample

OBJECTIVE

To investigate possible causes for previously reported glycemia-independent South Asian-white differences in HbA1c.

METHODS

Demographic and laboratory data on non-diabetic patients from primary care were analyzed. Linear regression models measured the association between race/ethnicity and three glycemic measures (HbA1c, fructosamine and fasting plasma glucose), adjusted for a range of hematological, biochemical and demographic factors.

RESULTS

Nine hundred and forty-eight patients consisting of 711 white subjects (407 women) and 237 South Asian subjects (138 women) were studied. Unadjusted bivariate analysis showed that South Asians had higher HbA1c concentrations [41 (5.9 %) vs. 40 (5.8 %) mmol/mol (p = 0.011), coefficient 1.21, 95 % CI 0.27, 2.17 (p = 0.011)] similar fructosamine [228.4 vs. 226.7 mmol/L (p = 0.352), coefficient 3.93, 95 % CI 0.79, 7.08 (p = 0.014)] and fasting plasma glucose [5.1 vs. 5.2 mmol/L (p = 0.154), coefficient -0.09, 95 % CI -0.22, -0.04 (p = 0.156)] concentrations than whites. South Asians also had lower hemoglobin, ferritin and vitamin B12 concentrations than whites. After adjustment for independent variables, South Asian ethnicity was associated with higher HbA1c concentrations [0.89, 95 % CI 0.06-1.72 (p = 0.035)], higher fructosamine levels [3.93, 95 % CI 0.79, 7.08 (p = 0.014)] and lower fasting plasma glucose concentrations [-0.12, 95 % CI -0.26, -0.02 (p = 0.026)] compared to white race.

CONCLUSIONS

The increased prevalence of hematological abnormalities in South Asians and their higher adjusted HbA1c and fructosamine but lower fasting glucose levels compared to white subjects suggest that ethnic differences in glycation markers may, in part, be due to a combination of erythrocyte factors and glycemia-independent glycation.

The value of HbA1c for diagnosing type 2 diabetes mellitus between Chinese Uyghurs and Hans in Xinjiang

OBJECTIVE

To compare the difference of glycosylated hemoglobin (HbA1c) for diagnosing type 2 diabetes mellitus (T2DM) between Chinese Uyghurs and Hans in xinjiang.

METHODS

we collected 707 subjects, including 456 Uyghurs and 251 Hans in Xinjiang Kashi region. All the subjects were underwent oral glucose tolerance test (OGTT) for diagnosing T2DM, at the same time their clinical biochemical markers and HbA1c levels were also measured. Then the data were analyzed, the receiver operating characteristic (ROC) curve was plotted and correlation analysis were made by SPSS 19.0 software.

RESULTS

1. The levels of body mess index (BMI), 2-hour plasma glucose (2 h PG), diastolic blood pressure (DBP) total cholestero (TC) and triglycerides (TG) were 26.6±4.75 kg/m(2), 14.3±6.2 mmol/l, 81.6±13.4 mmHg, 4.5±1.3 mmol/l and 4.3±2.8 mmol/l in Uyghurs, moreover those were higher than Hans [25.4±13.3 kg/m(2), 13.1±6.9 mmol/l, 78.4±9.9 mmHg, 2.3±2.1 mmol/l and 2.0±1.4 mmol/l, (P<0.05)]. 2. Otherwise, the optimal cut-off value for HbA1c to diagnose T2DM was 6.95% in Uyghurs. At this cut-off value, the sensitivity, specificity, positive likelihood ratio (+LR), negative likelihood ratio (-LR) and the area under the ROC curve (AUC) were 98.3%, 97.7%, 43.64, 0.017 and 0.997. While the optimal cut-off value was 7.05% in Hans, and, the sensitivity, specificity, +LR, -LR and AUC separately were 91.1%, 92.8%, 0.971, 12.6, 0.096 and 0.971. 3. The correlation analysis was made in two populations. It demonstrated that HbA1c was positively correlated with BMI, TC and TG in Uyghurs (r=0.138, 0.273, 0.482, P<0.05). However, in Hans, the HbA1c only was positively correlated with TG (r=0.178, P<0.05).

CONCLUSION

The Uyghurs have higher metabolic markers, for example, BMI, TC, DBP and TG. It reveals that Uyghurs may have more severe insulin resistance (IR) comparing with Hans. And then, the cut-off value of HbA1c for diagnosing and screening T2DM is different between Uyghurs and Hans in Xinjiang.

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.

Racial/Ethnic Differences in Insulin Resistance and Beta Cell Function: Relationship to Racial Disparities in Type 2 Diabetes among African Americans versus Caucasians

Both biological and sociocultural factors have been implicated in the well-documented racial disparity in incidence and prevalence of type 2 diabetes (T2D) between African Americans (AA) and non-Hispanic whites (NHW). This review examines the extent to which biological differences in glucose metabolism, specifically insulin resistance and beta cell function (BCF), contribute to this disparity. The majority of available data suggests that AA are more insulin resistant and have upregulated BCF compared to NHW. Increasing evidence implicates high insulin secretion as a cause rather than consequence of T2D; therefore, upregulated BCF in AA may specifically confer increased risk of T2D in this cohort. Racial disparities in the metabolic characteristics of T2D have direct implications for the treatment and health consequences of this disease; therefore, future research is needed to determine whether strategies to reduce insulin secretion in AA may prevent or delay T2D and lessen racial health disparities.

Association between Self-Reported Smoking and Hemoglobin A1c in a Korean Population without Diabetes: The 2011-2012 Korean National Health and Nutrition Examination Survey

Background

Several Western studies have revealed that among non-diabetics, glycosylated hemoglobin A1c (HbA1c) levels are higher in smokers than non-smokers. While studies conducted in Western populations consistently support this association, a recent meta-analysis reported that studies carried out in non-Western populations, including studies of Chinese, Egyptian, and Japanese-Americans, did not detect any significant differences in HbA1c levels between smokers and non-smokers.

Objectives

We assessed the association between smoking habits and HbA1c levels in the general Korean adult population using data from the Korean National Health and Nutrition Examination Survey (KNHANES) performed in 2011–2012.

Methods

A total of 10,241 participants (weighted n=33,946,561 including 16,769,320 men and 17,177,241 women) without diabetes were divided into four categories according to their smoking habits: never smokers (unweighted n/ weighted n= 6,349/19,105,564), ex-smokers (unweighted n/ weighted n= 1,912/6,207,144), current light smokers (<15 cigarettes per day, unweighted n/ weighted n=1,205/5,130,073), and current heavy smokers (≥15 cigarettes per day, unweighted n/ weighted n=775/3,503,781).

Results

In age- and gender-adjusted comparisons, the HbA1c levels of each group were 5.52 ± 0.01% in non-smokers, 5.49 ± 0.01% in ex-smokers, 5.53 ± 0.01% in light smokers, and 5.61 ± 0.02% in heavy smokers. HbA1c levels were significantly higher in light smokers than in ex-smokers (p = 0.033), and in heavy smokers compared with light smokers (p < 0.001). The significant differences remained after adjusting for age, gender, fasting plasma glucose, heavy alcohol drinking, hematocrit, college graduation, and waist circumference. Linear regression analyses for HbA1c using the above-mentioned variables as covariates revealed that a significant association between current smoking and HbA1c (coefficient 0.021, 95% CI 0.003–0.039, p = 0.019).

Conclusions

Current smoking was independently associated with higher HbA1c levels in a cigarette exposure-dependent manner in a representative population of Korean non-diabetic adults. In this study, we have observed an association between smoking status and HbA1c levels in non-diabetics drawn from a non-Western population, consistent with previous findings in Western populations.

Racial/ethnic disparities in prevalence and care of patients with type 2 diabetes mellitus

BACKGROUND

As of 2012, nearly 10% of Americans had diabetes mellitus. People with diabetes are at approximately double the risk of premature death compared with those in the same age groups without the condition. While the prevalence of diabetes has risen across all racial/ethnic groups over the past 30 years, rates are higher in minority populations. The objective of this review article is to evaluate the prevalence of diabetes and disease-related comorbidities as well as the primary endpoints of clinical studies assessing glucose-lowering treatments in African Americans, Hispanics, and Asians.

METHODS

As part of our examination of this topic, we reviewed epidemiologic and outcome publications. Additionally, we performed a comprehensive literature search of clinical trials that evaluated glucose-lowering drugs in racial minority populations. For race/ethnicity, we used the terms African American, African, Hispanic, and Asian. We searched PubMed for clinical trial results from 1996 to 2015 using these terms by drug class and specific drug. Search results were filtered qualitatively.

RESULTS

Overall, the majority of publications that fit our search criteria pertained to native Asian patient populations (i.e., Asian patients in Asian countries). Sulfonylureas; the α-glucosidase inhibitor, miglitol; the biguanide, metformin; and the thiazolidinedione, rosiglitazone have been evaluated in African American and Hispanic populations, as well as in Asians. The literature on other glucose-lowering drugs in non-white races/ethnicities is more limited.

CONCLUSIONS

Clinical data are needed for guiding diabetes treatment among racial minority populations. A multi-faceted approach, including vigilant screening in at-risk populations, aggressive treatment, and culturally sensitive patient education, could help reduce the burden of diabetes on minority populations. To ensure optimal outcomes, educational programs that integrate culturally relevant approaches should highlight the importance of risk-factor control in minority patients.

Association between the presence of iron deficiency anemia and hemoglobin A1c in Korean adults: the 2011-2012 Korea National Health and Nutrition Examination Survey

Few studies have investigated the clinical effect of iron deficiency anemia (IDA) on the use of the Hemoglobin A1c (HbA1c) as a screening parameter for diabetes or prediabetes. We investigated the association between IDA and HbA1c levels in Korean adults.Among the 11,472 adults (≥19 years of age) who participated in the 2011-2012 Korea National Health and Nutrition Examination Survey (a cross-sectional and nationally representative survey conducted by the Korean Center for Disease Control for Health Statistics), 807 patients with diabetes currently taking anti-diabetes medications were excluded from this study. We compared the weighted HbA1c levels and weighted proportion (%) of HbA1c levels of ≥5.7%, ≥6.1%, and ≥6.5% according to the range of fasting plasma glucose (FPG) levels and the presence of IDA.Among 10,665 participants (weighted n = 35,229,108), the prevalence of anemia and IDA was 7.3% and 4.3%, respectively. The HbA1c levels were higher in participants with IDA (5.70% ± 0.02%) than in normal participants (5.59% ± 0.01%; P < 0.001), whereas there was no significant difference in FPG levels. In participants with an FPG level of <100 mg/dL and 100 to 125 mg/dL, the weighted HbA1c level was higher in those with IDA (5.59% ± 0.02% and 6.00% ± 0.05%) than in normal participants (5.44% ± 0.01% and 5.82% ± 0.01%) after adjusting for confounders such as age, sex, FPG level, heavy alcohol drinking, waist circumference, and smoking status as well as after exclusion of an estimated glomerular filtration rate of <60 mL/min/1.73 m (P < 0.001, <0.01). The weighted proportions (%) of an HbA1c level of ≥5.7% and ≥6.1% were also higher in participants with IDA than in normal participants (P < 0.001, <0.05). However, the weighted HbA1c levels in individuals with an FPG level ≥126 mg/dL and a weighted proportion (%) of an HbA1c level of ≥6.5% showed no significant differences according to the presence of IDA.In conclusion, the presence of IDA shifted the HbA1c level upward only in the normoglycemic and prediabetic ranges, not in the diabetic range. Therefore, IDA should be considered before using HbA1c as a screening test for prediabetes.

Awareness of Prediabetes and Diabetes among Persons with Clinical Depression

Background. Major depressive disorder (MDD) is highly comorbid with diabetes, a relationship underappreciated by clinicians. Purpose. Examine the proportion of nonpregnant individuals ≥20 years with MDD and elevated glucose and the demographic and clinical characteristics associated with unrecognized elevated glucose. Methods. 14,373 subjects who participated in the National Health and Nutrition Examination Survey (2007-2012) completed the PHQ-9 depression screen and had hemoglobin A1C (HbA1c) measured. PHQ-9 scores ≥10 and HbA1c scores ≥5.7% were defined as MDD and elevated HbA1c, respectively. Data were analyzed using complex survey sampling software. Results. 38.4% of the sample with MDD had elevated HbA1c readings. Compared with nondepressed subjects, they were significantly more likely to have elevated glucose readings (P = 0.003) and to be aware of their elevated glucose levels if they had a higher body mass index, family history of diabetes, more doctor visits in the past year, a usual care source, health insurance, or were taking hypertension or hypercholesterolemia medications. Conclusions. Many adults with MDD have elevated HbA1c levels, have never been advised of elevated HbA1c, have not received diabetes screening, and have minimal contact with a healthcare provider. Additional opportunities for diabetes risk screening in people with MDD are needed.

Unfavorable inflammatory profile in adults at risk of type 2 diabetes identified by hemoglobin A1c levels according to the American Diabetes Association criteria

AIMS

We aimed to evaluate the inflammatory profile of individuals with prediabetes defined by HbA1c levels, according to the new American Diabetes Association criteria, and to determine the ability of HbA1c to identify individuals with subclinical inflammation independently of the contribution of other metabolic parameters such as fasting, 1- or 2-h post-load glucose (PG) levels.

METHODS

High sensitivity C-reactive protein (hsCRP), erythrocyte sedimentation rate (ESR), fibrinogen, white blood cells (WBC) count and complement C3 (C3) were assessed, and oral glucose tolerance test (OGTT) was performed in 711 adults.

RESULTS

Subjects were stratified into three groups according to their HbA1c levels. Poor agreement existed between HbA1c and 2-h PG criteria for identification of individuals with prediabetes (κ coefficient = 0.300). As compared with subjects having HbA1c <5.7 % (39 mmol/mol), individuals with prediabetes (HbA1c 5.7-6.4 %, [39-46 mmol/mol]) exhibited a significant increase of the concentration of five inflammatory markers (hsCRP, ESR, fibrinogen, WBC count, C3) as well as of a cluster of inflammatory markers, as measured by an inflammatory score after adjusting for sex, age, smoking, fasting, 1- and 2-h PG levels. In multiple regression models including sex, age, body mass index, smoking habit, fasting, 1- and 2-h PG levels, and HOMA index, HbA1c levels were significant independent contributors to each of the five inflammatory markers examined.

CONCLUSIONS

These data suggest that HbA1c is a reliable marker of glucose homeostasis, and may identify individuals at increased risk of diabetes with unfavorable inflammatory profile independently from fasting and 2-h PG levels.

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

AIMS

To 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.

METHODS

Women with GDM underwent a concurrent OGTT and HbA1c test 6-12 weeks postpartum.

RESULTS

There were 114 women with GDM who had a 75 g 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.

CONCLUSIONS

There 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.

Effect of chronic kidney disease on A1C in individuals being screened for diabetes

OBJECTIVE

Glycated haemoglobin (A1C) has been recommended for the diagnosis of type 2 diabetes mellitus. Chronic kidney disease (CKD) is reported to increase A1C. The prevalence of CKD and its association with A1C as a diagnostic test for type 2 diabetes screening in a community population was studied.

RESEARCH DESIGN AND METHODS

Age, gender, ethnicity (white/South Asian), haemoglobin, A1C, fasting glucose and fructosamine were compared in participants with estimated glomerular filtration rate (eGFR) 30-59 (CKD 3) and ≥60 ml/min/1.73 m(2) using chi-squared or t-tests. Multivariable linear regression analyses were performed with A1C as the dependent variable; remaining variables were forced into a model to identify correlates with A1C. Data were parametric and expressed as means.

RESULTS

Of 949 participants 83.7% had eGFR ≥60, 16.3% had CKD 3 and only 2 had eGFR <30 (CKD ≥4). Compared with eGFR ≥60, patients with CKD 3 were older [p<0.001], had higher A1C [6.0% vs. 5.8%, p<0.001], fasting glucose [5.4 vs. 5.2m mol/L, p=0.003] and fructosamine [233.7 vs. 225.8μ mol/L, p<0.001] but lower haemoglobin [p=0.006]. After adjustment, gender and CKD stage were not associated with A1C. A1C was associated (p<0.05) positively with age, South Asian ethnicity, fasting glucose and fructosamine and inversely with haemoglobin levels.

CONCLUSIONS

Severe CKD (stage ≥4) is rare in primary care patients being screened for type 2 diabetes and its impact on A1C could not be evaluated. Although A1C is higher among patients with CKD stage 3 compared to those with eGFR ≥60, this appeared to be due to the confounding effect of other variables rather than the presence of CKD.

Racial-ethnic disparities in management and outcomes among children with type 1 diabetes

BACKGROUND AND OBJECTIVES

Previous research has documented racial/ethnic disparities in diabetes treatments and outcomes. It remains controversial whether these disparities result from differences in socioeconomic status (SES) or other factors. We examined racial/ethnic disparities in therapeutic modalities and diabetes outcomes among the large number of pediatric participants in the T1D Exchange Clinic Registry.

METHODS

The cohort included 10 704 participants aged <18 years with type 1 diabetes for ≥1 year (48% female; mean age: 11.9 ± 3.6 years; diabetes duration: 5.2 ± 3.5 years). Diabetes management and clinical outcomes were compared among 8841 non-Hispanic white (white) (83%), 697 non-Hispanic black (black) (7%), and 1166 Hispanic (11%) participants. The population included 214 high-income black and Hispanic families.

RESULTS

Insulin pump use was higher in white participants than in black or Hispanic participants (61% vs 26% and 39%, respectively) after adjusting for gender, age, diabetes duration, and SES (P < .001). Mean hemoglobin A1c was higher (adjusted P < .001) in black participants than in white or Hispanic participants (9.6%, 8.4%, and 8.7%). More black participants experienced diabetic ketoacidosis and severe hypoglycemic events in the previous year than white or Hispanic participants (both, P < .001). There were no significant differences in hemoglobin A1c, diabetic ketoacidosis, or severe hypoglycemia between white and Hispanic participants after adjustment for SES.

CONCLUSIONS

Even after SES adjustment, marked disparities in insulin treatment method and treatment outcomes existed between black versus Hispanic and white children within this large pediatric cohort. Barriers to insulin pump use and optimal glycemic control beyond SES should be explored in all ethnic groups.

Association of visit-to-visit variability of hemoglobin A1c and medication adherence

BACKGROUND

Medication nonadherence is widespread, but there are few efficient means of detecting medication nonadherence at the point of care. Visit-to-visit variability in clinical biomarkers has shown inconsistent efficiency to predict medication adherence.

OBJECTIVE

To examine the performance of visit-to-visit variability (VVV) of hemoglobin A1c to predict nonadherence to antidiabetic medications.

METHODS

In this cross-sectional study using a clinical and administrative database, adult members of a managed care plan at a safety-net medical center from 2008 to 2012 were included if they had ≥ 3 noninsulin antidiabetic prescription fills within the same class and ≥ 3 A1c measurements between the first and last prescription fills. The independent variable was VVV of A1c (within-subject standard deviation of A1c), and the dependent variable was medication adherence (defined by medication possession ratio) determined from pharmacy claims. Unadjusted and adjusted multivariate logistic regression models were created to examine the relationship between VVV of A1c and medication nonadherence. Receiver-operating characteristic (ROC) curves assessed the performance of the adjusted model at discriminating adherence from nonadherence.

RESULTS

Among 632 eligible subjects, mean A1c was 7.7% ± 1.3%, and 83% of the sample was nonadherent to antidiabetic medications. Increasing quintiles of VVV of A1c and medication nonadherence were both associated with increased within-subject mean A1c and younger subject age. The logistic regression model (adjusted for age, sex, race/ethnicity, within-subject mean A1c, number of A1c measurements, number of days between the first and last antidiabetic medication prescription fills, and rate of primary care visits during the study period) showed a nonsignificant association of VVV of A1c and medication nonadherence (OR = 1.19, 95% CI = 0.42-3.38 for the highest quintile of VVV). Adding VVV of A1c to a model including age, sex, and race only modestly improved the C-statistic of the ROC curve from 0.6786 to 0.7064.

CONCLUSIONS

VVV of A1c is not a robust predictor of antidiabetic medication nonadherence. Further innovation is needed to develop novel methods of detecting nonadherence.

Racial disparities in outcomes following PEA and asystole in-hospital cardiac arrests

AIM

To define the racial differences present after PEA and asystolic IHCA and explore factors that could contribute to this disparity.

METHODS

We analyzed PEA and asystolic IHCA in the Get-With-The-Guidelines-Resuscitation database. Multilevel conditional fixed effects logistic regression models were used to estimate the relationship between race and survival to discharge and return of spontaneous circulation (ROSC), sequentially controlling for hospital, patient demographics, comorbidities, arrest characteristic, process measures, and interventions in place at time of arrest.

RESULTS

Among the 561 hospitals, there were 76,835 patients who experienced IHCA with an initial rhythm of PEA or asystole (74.8% white, 25.2% black). Unadjusted ROSC rate was 55.1% for white patients and 54.1% for black patients (unadjusted OR: 0.94 [95% CI, 0.90-0.98], p=0.016). Survival to discharge was 12.8% for white patients and 10.4% for black patients (unadjusted OR: 0.83 [95% CI, 0.78-0.87], p<0.001). After adjusting for temporal trends, patient characteristics, hospital, and arrest characteristics, there remained a difference in survival to discharge (OR: 0.85 [95% CI, 0.79-0.92]) and rate of ROSC (OR: 0.88 [95% CI, 0.84-0.92]). Black patients had a worse mental status at discharge after survival. Rates of DNAR placed after survival from were lower in black patients with a rate of 38.3% compared to 44.5% in white patients (p<0.001).

CONCLUSION

Black patients are less likely to experience ROSC and survival to discharge after PEA or asystole IHCA. Individual patient characteristics, event characteristics, and hospital characteristics don't fully explain this disparity. It is possible that disease burden and end-of-life preferences contribute to the racial disparity.

comparative study of glucose homeostasis, lipids and lipoproteins, HDL functionality, and cardiometabolic parameters in modestly severely obese African Americans and White Americans with prediabetes: implications for the metabolic paradoxes

OBJECTIVE

To determine whether modestly severe obesity modifies glucose homeostasis, levels of cardiometabolic markers, and HDL function in African Americans (AAs) and white Americans (WAs) with prediabetes.

RESEARCH DESIGN AND METHODS

We studied 145 subjects with prediabetes (N = 61 WAs, N = 84 AAs, mean age 46.5 ± 11.2 years, mean BMI 37.8 ± 6.3 kg/m(2)). We measured fasting levels of lipids, lipoproteins, and an inflammatory marker (C-reactive protein [CRP]); HDL functionality (i.e., levels of paraoxonase 1 [PON1]); and levels of oxidized LDL, adiponectin, and interleukin-6 (IL-6). We measured serum levels of glucose, insulin, and C-peptide during an oral glucose tolerance test. Values for insulin sensitivity index (Si), glucose effectiveness index (Sg), glucose effectiveness at zero insulin (GEZI), and acute insulin response to glucose (AIRg) were derived using a frequently sampled intravenous glucose tolerance test (using MINMOD software).

RESULTS

Mean levels of fasting and incremental serum glucose, insulin, and C-peptide tended to be higher in WAs versus AAs. The mean Si was not different in WAs versus AAs (2.6 ± 2.3 vs. 2.9 ± 3.0 × 10(-4) × min(-1) [μU/mL](-1)). Mean values for AIRg and disposition index as well as Sg and GEZI were lower in WAs than AAs. WAs had higher serum triglyceride levels than AAs (116.1 ± 55.5 vs. 82.7 ± 44.2 mg/dL, P = 0.0002). Mean levels of apolipoprotein (apo) A1, HDL cholesterol, PON1, oxidized LDL, CRP, adiponectin, and IL-6 were not significantly different in obese AAs versus WAs with prediabetes.

CONCLUSIONS

Modestly severe obesity attenuated the ethnic differences in Si, but not in Sg and triglyceride levels in WAs and AAs with prediabetes. Despite the lower Si and PON1 values, AAs preserved paradoxical relationships between the Si and HDL/apoA1/triglyceride ratios. We conclude that modestly severe obesity has differential effects on the pathogenic mechanisms underlying glucose homeostasis and atherogenesis in obese AAs and WAs with prediabetes.

The optimal cutoff value of glycated hemoglobin for detection of diabetic retinopathy

With standardization of measurement of glycated hemoglobin (A1C), the International Expert Committee Report in 2009 and the American Diabetes Association in 2010 recommended incorporating A1C ≥6.5% into the previous diagnostic criteria using fasting plasma glucose and/or 2-hour plasma glucose. Whereas the association of A1C with cardiovascular diseases and other diabetic microvascular complications was linear without evidence of a distinct threshold, several studies suggested a threshold value for A1C in diabetic retinopathy (DR). In studies about the optimal cutoff value for A1C in DR, the A1C values range from 5.2% to 7.8%. There are several possible reasons why these values for DR differ so widely (differences in the definition and/or methods for DR, variation in statistical methods, differences in study population, differences in exclusion criteria, and difference in methods for measuring A1C). With these wide variations in the study method, drawing a conclusive cutoff value for A1C in DR is impossible. In published studies, the cutoff values for moderate or severe DR were higher than those for any or mild DR (6.4% to 7.0% vs. 5.5% to 6.5%).

Glycosylated hemoglobin testing in the National Social Life, Health, and Aging Project

OBJECTIVES

Longitudinal biomeasures of health are still new in nationally representative social science survey research. Data measuring blood sugar control provide opportunities for understanding the development of diabetes and its complications in older adults, but researchers must be aware that some of the differences across time can be due to variations in measurement procedures. This is a well-recognized issue whenever all samples cannot be assayed at the same time and we sought to present the analytic methods to quantify and adjust for the variation.

METHOD

We collected and analyzed HbA1C, glycated hemoglobin, a biomeasure of average blood sugar concentrations within the past few months. Improvements were made in the collection protocol for Wave 2, and assays were performed by a different lab.

RESULTS

The HbA1C data obtained during Wave 1 and Wave 2 are consistent with the expected population distributions for differences by gender, age, race/ethnicity, and diabetes status. Age-adjusted mean HbA1C declined slightly from Wave 1 to Wave 2 by -0.19 (95% confidence interval [CI]: -0.27, -0.10), and the average longitudinal change was -0.12 (95% CI: -0.18, -0.06).

DISCUSSION

Collection of HbA1C in Wave 2 permits researchers to examine the relationship between HbA1C and new health and social measures added in Wave 2, and to identify factors related to the change in HbA1C. Changes in collection protocol and labs between waves may have yielded small systematic differences that require analysts to carefully interpret absolute HbA1C values. We recommend analytic methods for cross wave differences in HbA1C and steps to ensure cross wave comparability in future studies.

Trends in diabetes incidence among 7 million insured adults, 2006-2011: the SUPREME-DM project

An observational cohort analysis was conducted within the Surveillance, Prevention, and Management of Diabetes Mellitus (SUPREME-DM) DataLink, a consortium of 11 integrated health-care delivery systems with electronic health records in 10 US states. Among nearly 7 million adults aged 20 years or older, we estimated annual diabetes incidence per 1,000 persons overall and by age, sex, race/ethnicity, and body mass index. We identified 289,050 incident cases of diabetes. Age- and sex-adjusted population incidence was stable between 2006 and 2010, ranging from 10.3 per 1,000 adults (95% confidence interval (CI): 9.8, 10.7) to 11.3 per 1,000 adults (95% CI: 11.0, 11.7). Adjusted incidence was significantly higher in 2011 (11.5, 95% CI: 10.9, 12.0) than in the 2 years with the lowest incidence. A similar pattern was observed in most prespecified subgroups, but only the differences for persons who were not white were significant. In 2006, 56% of incident cases had a glycated hemoglobin (hemoglobin A1c) test as one of the pair of events identifying diabetes. By 2011, that number was 74%. In conclusion, overall diabetes incidence in this population did not significantly increase between 2006 and 2010, but increases in hemoglobin A1c testing may have contributed to rising diabetes incidence among nonwhites in 2011.

The efficacy and safety of canagliflozin across racial groups in patients with type 2 diabetes mellitus

OBJECTIVE

Canagliflozin, a sodium-glucose co-transporter 2 inhibitor, enhances urinary glucose excretion through an insulin-independent mode of action, and improves glycemic control in patients with type 2 diabetes mellitus (T2DM). This study assessed the efficacy and safety of canagliflozin across racial groups.

METHODS

The efficacy of canagliflozin 100 mg and 300 mg was evaluated by racial group using data pooled from four placebo-controlled phase 3 studies and two placebo-controlled sub-studies of a population of patients with inadequately controlled T2DM (N = 4158). Least-squares mean changes from baseline were calculated for hemoglobin A1c (HbA1c), systolic blood pressure (SBP), body weight (BW), cholesterol, and triglycerides. Safety/tolerability evaluation included reporting of general and prespecified adverse events (AEs).

RESULTS

A total of 75% of patients were White, 13% were Asian, 4% were Black/African American, and 8% were 'Other' (American Indian, Alaskan Native, mixed race, Native Hawaiian or other Pacific Islander, not reported, and unknown). Baseline demographics were similar for these groups. Dose-related reductions in HbA1c, BW, and SBP were observed with both canagliflozin doses in all racial groups. Canagliflozin was generally safe and well tolerated. Treatment with canagliflozin was associated with an increased rate of genital mycotic infections (GMIs) and urinary tract infections (UTIs) in all racial groups. GMIs were observed more often in Black/African American males and males from the 'Other' racial group, whereas UTIs and osmotic diuresis-related AEs were less common in Asians. Key study limitations include the high proportion of White patients compared with other racial groups and the fact that included studies were not powered to evaluate racial differences.

CONCLUSION

Canagliflozin was generally well tolerated and consistently associated with reductions in HbA1c, BW, and SBP in patients with T2DM independent of racial background. (ClinicalTrials.gov numbers: NCT01081834; NCT01106677; NCT01106625; NCT01106690; and NCT01032629.).

Optimal Hemoglobin A1c Levels for Screening of Diabetes and Prediabetes in the Japanese Population

The aim of this study was to evaluate the utility of hemoglobin A1c (HbA1c) to identify individuals with diabetes and prediabetes in the Japanese population. A total of 1372 individuals without known diabetes were selected for this study. A 75 g oral glucose tolerance test (OGTT) was used to diagnose diabetes and prediabetes. The ability of HbA1c to detect diabetes and prediabetes was investigated using receiver operating characteristic (ROC) analysis. The kappa (κ) coefficient was used to test the agreement between HbA1c categorization and OGTT-based diagnosis. ROC analysis demonstrated that HbA1c was a good test to identify diabetes and prediabetes, with areas under the curve of 0.918 and 0.714, respectively. Optimal HbA1c cutoffs for diagnosing diabetes and prediabetes were 6.0% (sensitivity 83.7%, specificity 87.6%) and 5.7% (sensitivity 60.6%, specificity 72.1%), respectively, although the cutoff for prediabetes showed low accuracy (67.6%) and a high false-negative rate (39.4%). Agreement between HbA1c categorization and OGTT-based diagnosis was low in diabetes (κ = 0.399) and prediabetes (κ = 0.324). In Japanese subjects, the HbA1c cutoff of 6.0% had appropriate sensitivity and specificity for diabetes screening, whereas the cutoff of 5.7% had modest sensitivity and specificity in identifying prediabetes. Thus, HbA1c may be inadequate as a screening tool for prediabetes.

Diabetes Complications at Presentation and One Year by Glycated Haemoglobin at Diagnosis in a Multiethnic and Diverse Socioeconomic Population: Results from the South London Diabetes Study

Background. WHO's recommendation of HbA1c ≥ 48 mmol/mol (6.5%) as diagnostic for type 2 diabetes mellitus (T2DM) was adopted by three UK London boroughs in May 2012. The South London Diabetes (SOUL-D) study has recruited people with newly diagnosed T2DM since 2008. We compared participants diagnosed before May 2012 with HbA1c < 48 mmol/mol to those with diagnostic HbA1c ≥ 48 mmol/mol. Methods. A prospective cohort study of newly diagnosed T2DM participants from 96 primary care practices, comparing demographic and biomedical variables between those with diagnostic HbA1c < 48 mmol/mol or HbA1c ≥ 48 mmol/mol at recruitment and after one year. Results. Of 1488 participants, 22.8% had diagnostic HbA1c < 48 mmol/mol. They were older and more likely to be white (p < 0.05). At recruitment and one year, there were no between-group differences in the prevalence of diabetic complications, except that those diagnosed with HbA1c < 48 mmol/mol had more sensory neuropathy at recruitment (p = 0.039) and, at one year, had new myocardial infarction (p = 0.012) but less microalbuminuria (p = 0.012). Conclusions. Use of HbA1c ≥ 48 mmol/mol as the sole T2DM diagnostic criterion may miss almost a quarter of those previously diagnosed in South London yet HbA1c < 48 mmol/mol may not exclude clinically important diabetes.

HbA1c as a predictor of diabetes and as an outcome in the diabetes prevention program: a randomized clinical trial

OBJECTIVE

Glycated hemoglobin (HbA1c), a standard measure of chronic glycemia for managing diabetes, has been proposed to diagnose diabetes and identify people at risk. The Diabetes Prevention Program (DPP) was a 3.2-year randomized clinical trial of preventing type 2 diabetes with a 10-year follow-up study, the DPP Outcomes Study (DPPOS). We evaluated baseline HbA1c as a predictor of diabetes and determined the effects of treatments on diabetes defined by an HbA1c ≥6.5% (48 mmol/mol).

RESEARCH DESIGN AND METHODS

We randomized 3,234 nondiabetic adults at high risk of diabetes to placebo, metformin, or intensive lifestyle intervention and followed them for the development of diabetes as diagnosed by fasting plasma glucose (FPG) and 2-h postload glucose (2hPG) concentrations (1997 American Diabetes Association [ADA] criteria). HbA1c was measured but not used for study eligibility or outcomes. We now evaluate treatment effects in the 2,765 participants who did not have diabetes at baseline according to FPG, 2hPG, or HbA1c (2010 ADA criteria).

RESULTS

Baseline HbA1c predicted incident diabetes in all treatment groups. Diabetes incidence defined by HbA1c ≥6.5% was reduced by 44% by metformin and 49% by lifestyle during the DPP and by 38% by metformin and 29% by lifestyle throughout follow-up. Unlike the primary DPP and DPPOS findings based on glucose criteria, metformin and lifestyle were similarly effective in preventing diabetes defined by HbA1c.

CONCLUSIONS

HbA1c predicted incident diabetes. In contrast to the superiority of the lifestyle intervention on glucose-defined diabetes, metformin and lifestyle interventions had similar effects in preventing HbA1c-defined diabetes. The long-term implications for other health outcomes remain to be determined.

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

Aim

To 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).

Methods

Glucose 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.

Results

HbA1c 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.

Conclusion

Proposed 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.

•

We compare the performance of HbA1c with established glucose criteria during an oral glucose tolerance test (OGTT).

•

We also assess HbA1c as a screening test for undiagnosed diabetes and pre-diabetes after gestational diabetes mellitus.

•

Proposed thresholds of HbA1c had low diagnostic sensitivity relative to OGTT.

•

Combining HbA1c with a fasting glucose test the performance was no better than using a fasting glucose test alone.

•

Combining a fasting glucose test with a lower HbA1c cut-point may be an option for selection of women for an OGTT.

An early pregnancy HbA1c ≥5.9% (41 mmol/mol) is optimal for detecting diabetes and identifies women at increased risk of adverse pregnancy outcomes

OBJECTIVE

Pregnant women with undiagnosed diabetes are a high-risk group that may benefit from early intervention. Extrapolating from nonpregnancy data, HbA1c ≥6.5% (48 mmol/mol) is recommended to define diabetes in pregnancy. Our aims were to determine the optimal HbA1c threshold for detecting diabetes in early pregnancy as defined by an early oral glucose tolerance test (OGTT) at <20 weeks' gestation and to examine pregnancy outcomes relating to this threshold.

RESEARCH DESIGN AND METHODS

During 2008-2010 in Christchurch, New Zealand, women were offered an HbA1c measurement with their first antenatal bloods. Pregnancy outcome data were collected. A subset completed an early OGTT, and HbA1c performance was assessed using World Health Organization criteria.

RESULTS

HbA1c was measured at a median 47 days' gestation in 16,122 women. Of those invited, 974/4,201 (23%) undertook an early OGTT. In this subset, HbA1c ≥5.9% (41 mmol/mol) captured all 15 cases of diabetes, 7 with HbA1c <6.5% (<48 mmol/mol). This HbA1c threshold was also 98.4% (95% CI 97-99.9%) specific for gestational diabetes mellitus (GDM) before 20 weeks (positive predictive value = 52.9%). In the total cohort, excluding women referred for GDM management, women with HbA1c of 5.9-6.4% (41-46 mmol/mol; n = 200) had poorer pregnancy outcomes than those with HbA1c <5.9% (<41 mmol/mol; n = 8,174): relative risk (95% CI) of major congenital anomaly was 2.67 (1.28-5.53), preeclampsia was 2.42 (1.34-4.38), shoulder dystocia was 2.47 (1.05-5.85), and perinatal death was 3.96 (1.54-10.16).

CONCLUSIONS

HbA1c measurements were readily performed in contrast to the low uptake of early OGTTs. HbA1c ≥5.9% (≥41 mmol/mol) identified all women with diabetes and a group at significantly increased risk of adverse pregnancy outcomes.

Performance of glycated haemoglobin (HbA1c) as a screening test for diabetes and impaired glucose tolerance (IGT) in a high risk population--the Brazilian Xavante Indians

AIMS

To examine the properties of HbA1c to detect diabetes and IGT in adult Brazilian Xavante Indians, a high risk population for diabetes.

METHODS

The survey was carried out between October 2010 and January 2012 and based on a 75 g oral glucose tolerance test (OGTT). Basal and 2h capillary glycaemia were measured by HemoCue Glucose 201+; HbA1c using an automated high-performance liquid chromatography analyzer (Tosoh G7).

RESULTS

630 individuals aged ≥ 20 years were examined and 80 had a previous diagnosis of diabetes. Sensitivity, specificity and accuracy for HbA1c ≥ 6.5% (≥ 48 mmol/mol) were 71.3%, 90.5% and 87.2%. The areas under the ROC curve (AUC) was 0.88 (95%CI: 0.83-0.93). To identify IGT, HbA1c values between 5.7% and 6.4% (39-47 mmol/mol) presented sensitivity, specificity and accuracy of 87.2%, 24.7% and 51.4%, with an AUC of 0.62 (95%CI: 0.57-0.67).

CONCLUSIONS

The ADA/WHO proposed cut-off of 6.5% (48 mmol/mol) for HbA1c was adequate to detect diabetes among the Xavante. However, the performance of the ADA proposed cut-off points for pre-diabetes, when used to detect IGT was inadequate and should not be recommended.

Prevalence of hemoglobin variants in a diabetic population at high risk of hemoglobinopathies and optimization of HbA1c monitoring by incorporating HPLC in the laboratory workup

BACKGROUND

In Tunisia, diabetes mellitus and hemoglobinopathies are major public health problems. Glycated hemoglobin (HbA1c) is recommended for long-term monitoring of diabetes mellitus, but the presence of hemoglobin variants may interfere with HbA1c measurement. The aim was to determine the prevalence of hemoglobin variants in Tunisian diabetics and optimize the monitoring of diabetics using HbA1c.

METHODS

The study enrolled 9,792 Tunisian diabetic patients. HbA1c was measured by cation-exchange high-pressure liquid chromatography (HPLC). All the chromatograms were analyzed for the presence of Hb variants.

RESULTS

We identified 228 cases (2.33%) of Hb variants with D-10 HPLC (Bio-Rad): 191 with HbA/S trait, 27 with HbA/C trait, and 10 hemoglobin variants with the mention 'Variant-Window' on the chromatograms and subsequently identified as HbA/S on Variant I HPLC (Bio-Rad). Thus, the prevalence of HbS was 2.05%. We did not find any homozygous variant. All HbA1c results were reported to the treating physician.

CONCLUSIONS

To evaluate glycated hemoglobin in populations with a high prevalence of hemoglobinopathies, we should use the HPLC method, which is easy, economical, and reliable. Based on an algorithm, hemoglobin variants visualized on HPLC should be reported to the physician to improve the management of patients.

Financial strain, inflammatory factors, and haemoglobin A1c levels in African American women

OBJECTIVE

Type 2 diabetes disproportionately affects African American women, a population exposed to high levels of stress, including financial strain (Centers for Disease Control & Prevention, 2011, http://www.cdc.gov/diabetes/pubs/pdf/ndfs_2011.pdf). We tested a mediational model in which chronic financial strain among African American women contributes to elevated serum inflammation markers, which, in turn, lead to increased haemoglobin A1C (HbA1c) levels and risk for type 2 diabetes.

METHODS

We assessed level of financial strain four times over a 10-year period and tested its effect on two serum inflammation markers, C-reactive protein (CRP) and soluble interleukin-6 receptor (sIL-6R) in year 11 of the study. We tested the inflammation markers as mediators in the association between chronic financial strain and HbA1c, an index of average blood glucose level over several months.

DESIGN

Data were from 312 non-diabetic African American women from the Family and Community Health Study (FACHS; Cutrona et al., 2000, J. Pers. Soc. Psychol., 79, 1088).

RESULTS

Chronic financial strain predicted circulating sIL-6R after controlling for age, BMI, health behaviours, and physical health measures. In turn, sIL-6R significantly predicted HbA1c levels. The path between chronic financial strain and HbA1c was significantly mediated by sIL-6R. Contrary to prediction, CRP was not predicted by chronic financial strain.

CONCLUSIONS

Results support the role of inflammatory factors in mediating the effects of psychosocial stressors on risk for type 2 diabetes. Findings have implications for interventions that boost economic security and foster effective coping as well as medical interventions that reduce serum inflammation to prevent the onset of type 2 diabetes.

Low positive predictive value of hemoglobin A1c for diagnosis of prediabetes in clinical practice

BACKGROUND

Positive predictive value (PPV) of hemoglobin A1c (HbA1c) for diagnosis of prediabetes in clinical practice has not been well studied.

METHODS

In a prospective study, patients diagnosed with prediabetes based on HbA1c (5.7%-6.4%) underwent a 75-g oral glucose tolerance test (OGTT) as the gold standard test to diagnose dysglycemia. Demographics, anthropometrics, comorbidity, concomitant prescription medications and biochemical data were collected.

RESULTS

We identified 66 patients with HbA1c-based prediabetes with a mean HbA1c of 6.00 ± 0.20%. However, based on the OGTT, 32 had normal glucose tolerance (NGT), 26 had prediabetes and 8 had diabetes yielding a PPV of HbA1c of 39.4%. In univariate analysis, the patients with the OGTT-based prediabetes administered more medications for associated medical problems compared with the NGT group (5.9 ± 2.2 versus 2.6 ± 1.8, P < 0.0001). After adjustment for baseline variables, the medication use remained significantly different between OGTT-based prediabetes and NGT groups (P = 0.041).

CONCLUSIONS

PPV of HbA1c for diagnosis of prediabetes in clinical setting is low. Patients with HbA1c of 5.7% to 6.4% should undergo OGTT to confirm diagnosis of dysglycemia.

Is early postpartum HbA1c an appropriate risk predictor after pregnancy with gestational diabetes mellitus?

Compared to the 2-h oral glucose tolerance test (OGTT), the assessment of HbA1c was proposed as a less time-consuming alternative to detect pathologies in carbohydrate metabolism. This report aims to assess the predictive accuracy of HbA1c to detect alterations in glucose disposition early after gestational diabetes mellitus (GDM) pregnancy. A detailed metabolic characterization was performed in 77 women with previous GDM (pGDM) and 41 controls 3-6 month after delivery: 3-h OGTT, frequently sampled intravenous glucose tolerance test. Follow-up examinations of pGDMs were performed up to 10 years. HbA1c (venous samples, HPLC) was assessed at baseline as well as during the follow-up period (475 patient contacts). Moderate associations were observed between HbA1c and measurements of plasma glucose during the OGTT at the baseline examination: The strongest correlation was found for FPG (r = 0.40, p < 0.001), decreasing after ingestion. No associations were detected between HbA1c and OGTT dynamics of insulin or C-peptide. Moreover, baseline HbA1c showed only modest correlation with insulin sensitivity (r = -0.25, p = 0.010) and disposition index (r = -0.26, p = 0.007). A linear model including fasting as well as post-load glucose levels was not improved by HbA1c. However, pGDM females with overt diabetes manifestation during the follow-up period showed more pronounced increasing HbA1c in contrast to females remaining normal glucose tolerant or developing prediabetes. It is suggested that the performance of HbA1c assessed early after delivery is inferior to the OGTT for the detection of early alterations in glucose metabolism. However, an increase in HbA1c levels could be used as an indicator of risk for diabetes manifestation.

Screening for metabolic and reproductive complications in obese children and adolescents

Childhood obesity is associated with a number of metabolic comorbidities. These include glucose intolerance and type 2 diabetes mellitus, hyperlipidemia, fatty liver disease, and reproductive complications, such as polycystic ovary syndrome. The occurrence of these complications in a child or adolescent may result in progressive health decline at an early age. We, therefore, advocate screening and early diagnosis. This purpose of this review is to outline a rational, evidence-based approach to screening obese children and adolescents for metabolic and reproductive complications. In each section, the aim is to provide the primary care provider with a review of the literature supporting current screening practices. As such, this review is designed to assist the primary care provider in the selection and interpretation of screening tests and to make recommendations regarding the referral of patients for subspecialty care.

Consequences of Abdominal Adiposity within the Metabolic Syndrome Paradigm in Black People of African Ancestry

The metabolic syndrome (MetS) is a constellation of risk factors that are associated with increased risks for coronary heart disease and type 2 diabetes. Although the cause is unknown, abdominal adiposity is considered the underpinning of these metabolic alterations. Hence, increased abdominal adiposity contributes to dyslipidemia, hyperglycemia, beta cell dysfunction, insulin resistance, hypertension and inflammation. The role of abdominal adiposity in the causation of metabolic alterations that lead to the clinical expression of the MetS has become a focus of active research. In addition, there are ethnic/racial differences in the manifestation of the MetS. Therefore, the focus of this current review is to: (1) explore the consequences of abdominal obesity within the MetS paradigm; and (2) discuss the impact of ethnicity/race on MetS in Black People of African Ancestry (PAA).

Management of diabetes mellitus type-2 in the geriatric population: Current perspectives

The prevalence of diabetes mellitus (DM) has increased exponentially throughout the world and there is rapid increase in elderly diabetics. DM is associated with increased mortality and considerable morbidity including stroke, heart disease, and diminished quality of life in the elderly. However, the unique features of geriatric diabetes have not been given due a prominence in medical literature. Hypoglycemia remains the biggest complicating factor and needs to be avoided in the elderly. Most people in the geriatric age group have some degree of renal insufficiency and medications need to be adjusted wisely with changing renal profile. Because safer and more effective pharmacological therapy is available, an individual approach to DM in the elderly is essential.

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.

Impact of hemoglobin A1c-based criterion on diagnosis of prediabetes: The Korea National Health and Nutrition Examination Survey 2011

To examine the impact of hemoglobin A1c (HbA1c) criterion on the diagnosis of prediabetes in Koreans, we analyzed nationally representative cross-sectional data of 5,845 Korean adults aged ≥20 years from the Fifth Korea National Health and Nutrition Examination Survey 2011. Standardized prevalence rates of prediabetes in Korean adults by fasting plasma glucose (FPG; 5.6–6.9 mmol/L), HbA1c (5.7–6.4% [39–46 mmol/mol]), and combined criteria were 16.9, 28.4 and 33.8%, respectively. Among the subjects with prediabetes, 16% met FPG criteria only, 55% met HbA1c criteria only and 29% met both criteria. Prediabetic subjects who met HbA1c criteria only were significantly older, more likely to be women, and had lower hemoglobin and serum iron concentrations, whereas those who met FPG criteria only had higher body mass index, waist circumference, systolic and diastolic blood pressure. In conclusion, introduction of HbA1c criterion markedly increased the prevalence of prediabetes in Koreans, and the two criteria identified people with different characteristics.

Ethnic variation in the correlation between fasting glucose concentration and glycated hemoglobin (HbA1c)

OBJECTIVE

We aimed to determine the relationship between fasting serum glucose (FSG) concentration and glycated hemoglobin-A1c (HbA1c) in the 3 ethnicities in Singapore after adjustment for demographic and therapeutic variables.

METHODS

Fasting serum glucose (FSG), HbA1c, and serum creatinine levels were simultaneously sampled from 575 patients with diabetes (389 Chinese, 97 Indians, 89 Malays) in this cross-sectional study between January and May 2008, and the results were subjected to multivariate linear regression analysis.

RESULTS

We found a significant interaction between FSG and ethnicity on HbA1c. The correlation between FSG and HbA1c among Chinese subjects was 0.25 (95% confidence interval [CI]:0.2-0.3) relative to the Malays (0.38, 95% CI: 0.30-0.45) after adjustment for age; gender; serum creatinine concentrations; body mass index (BMI); duration of diabetes; use of sulfonylureas, metformin, and insulin; and hemoglobin (Hb) and red cell indices (P = .005). Hence, for a given FSG, the predicted HbA1c will be higher in Malays compared to Chinese subjects. We did not observe a statistically significant difference between Indians and Malays with respect to the correlation between FSG and HbA1c.

CONCLUSION

We showed a higher correlation between HbA1c and FSG in Malay subjects relative to the Chinese in this cohort. The ethnic variation in the HbA1c-FSG relationship may be related to differences in percentage contribution by the FSG to overall HbA1c among ethnic groups. Future studies using continuous glucose monitoring (CGM) to elucidate the relative contributions by FSG and postprandial glucose (PPG) to the daily blood glucose profile and the overall HbA1c by ethnicity are required.

Glycated haemoglobin A₁c for diagnosing diabetes in Chinese subjects over 50 years old: a community-based cross-sectional study

OBJECTIVE

Little is known about using glycated haemoglobin A₁c (HbA₁c) to diagnose diabetes in Chinese subjects over 50 years old. This study aims to evaluate HbA₁c in diagnosing diabetes and identify the optimal threshold to be used in Chinese community subjects aged over 50 years.

METHODS

A community-based cross-sectional survey was conducted from October 2010 to January 2011 in Shipai community of Guangzhou, Guangdong, China. A total of 1494 subjects (72·8%) aged over 50 years were investigated. Fasting plasma glucose (FPG₁st ) and HbA₁c were assayed in each participant. Diabetic candidates with FPG₁st ≥ 5·6 mmol/l or HbA₁c ≥ 39 mmol/mol (5·7%) were informed to undergo a 75-g oral glucose tolerance test (OGTT). Diagnosis of diabetes was made by 1999 World Health Organization criteria. Sensitivity and specificity of HbA1 c for diagnosing diabetes were calculated by receiver operating characteristics (ROC) curve.

RESULTS

Among 1494 subjects, 161 subjects (10·8%) with previously diagnosed diabetes and 21 with missing data were excluded. Among the remaining 1312 subjects (87·8%), 861 subjects (65·6%) with either FPG1st ≥ 5·6 mmol/l or HbA₁c ≥ 39 mmol/mol (5·7%) were invited to perform OGTT. Finally, 453 subjects (52·6%) performed OGTT (FPG₂nd and 2-h plasma glucose were measured) and 54 subjects (11·9%) were identified as being diabetes. The area under ROC curve was 0·916 (0·887-0·940) for HbA₁c and 0·972 (0·953-0·985) for FPG₂nd in diagnosing diabetes (P = 0·045). An HbA₁c threshold of 48 mmol/mol (6·5%) yielded the highest combination of sensitivity (75·9%) and specificity (95·5%) for diagnosing diabetes.

CONCLUSION

An HbA1 c threshold of 48 mmol/mol (6·5%) was highly specific and had a good sensitivity for diagnosing diabetes among Chinese subjects aged over 50 years with FPG ≥ 5·6 mmol/l or HbA₁c ≥ 39 mmol/mol (5·7%). This threshold may be suitable for diagnosing diabetes in Chinese subjects over 50 years old.

A psychosocial risk index for poor glycemic control in children and adolescents with type 1 diabetes

OBJECTIVE

The aim of this study was to develop and validate a psychosocial screening tool to predict risk for poor glycemic control in children with type 1 diabetes.

METHODS

Participants seen for psychological screening were 196 children aged 3-18 yr at diabetes diagnosis. A psychosocial risk index was developed to predict poor glycemic control [mean hemoglobin A1c (HbA1c) ≥ 9.5%; 80 mmol/mol] 1-4 yr post diagnosis. Cutoff scores were derived for multiple levels of risk from receiver operating characteristic (ROC) curves and likelihood ratios (LRs). Discrimination and calibration were examined in the sample, and validated in 1000 bootstrap samples. Ability to predict diabetes-related emergency-room (ER) visits and diabetic ketoacidosis (DKA) was also tested.

RESULTS

The risk index accounted for 16.2% of variance in mean HbA1c, discriminated between children with and without poor glycemic control [area under the receiver operating characteristic curve (AUC) = 0.814, 0.713-0.915; p < 0.001], ER visits (AUC = 0.655, 0.561-0.748; p = 0.001), and DKA(AUC = 0.709, 0.588-0.830; p = 0.001), and was well-calibrated. Every one-point increase in score was associated with an absolute increase in risk for poor glycemic control of approximately 10% (LRs = 1.7, 3.2, 5.8, and 9.3). Sensitivity and specificity were 0.68 (0.43-0.86) and 0.79 (0.72-0.84) for detecting patients at moderate risk, and 0.53 (0.29-0.75) and 0.91 (0.85-0.95) for detecting high-risk patients. The index performed equally well in validation samples.

CONCLUSIONS

This paper presents the first psychosocial risk index for poor glycemic control in children newly diagnosed with type 1 diabetes. It is brief, easily administered, and provides a single score that translates directly into an estimate of risk that can help guide routine diabetes care.

Comparative associations of diabetes risk factors with five measures of hyperglycemia

OBJECTIVE

To compare the associations of diabetes mellitus risk factors with nontraditional markers of hyperglycemia (glycated albumin, fructosamine, 1,5-anhydroglucitol (1,5-AG)) to those observed with traditional markers (fasting glucose, hemoglobin A1c (HbA1c)).

DESIGN

Cross-sectional study.

SETTING

The community-based Atherosclerosis Risk in Communities (ARIC) Study cohort.

PARTICIPANTS

A subsample of 1764 participants (309 with diagnosed diabetes and 1455 without diagnosed diabetes) from the ARIC Study who attended a clinic visit in 2005-2006.

MAIN OUTCOME MEASURES

Elevated levels of glycated albumin, fructosamine, 1,5-AG, fasting glucose, and HbA1c in persons with and without a diagnosis of diabetes.

RESULTS

The mean age of participants was 70 years (SD, 6), 43% were men, and 20% were African-American. Black race and family history of diabetes were generally positively associated with elevated levels of all biomarkers of hyperglycemia except 1,5-AG, which showed inverse but weaker associations with the risk factors examined. In general, patterns of risk factor associations observed for fasting glucose and HbA1c were similar to those observed for the nontraditional biomarkers of hyperglycemia but with one clear exception: body mass index (BMI). In persons without a diagnosis of diabetes, BMI was positively associated with fasting glucose and HbA1c, but the associations of BMI with glycated albumin and fructosamine were inverse, with high values of these markers at low levels of BMI. 1,5-AG, which is lowered in the setting of hyperglycemia, was positively associated with BMI.

CONCLUSIONS

Traditional diabetes risk factors have similar associations with glycated albumin and fructosamine as those for fasting glucose and HbA1c, with the exception of BMI. Risk factor associations with 1,5-AG were mostly inverse. The inverse associations of BMI with glycated albumin and fructosamine, and positive associations with 1,5-AG, may reflect pathways independent of glucose metabolism and merit further examination.

Rational use of electronic health records for diabetes population management

Population management is increasingly invoked as an approach to improve the quality and value of diabetes care. Recent emphasis is driven by increased focus on both costs and measures of care as the US moves from fee for service to payment models in which providers are responsible for costs incurred, and outcomes achieved, for their entire patient population. The capacity of electronic health records (EHRs) to create patient registries, apply analytic tools, and facilitate provider- and patient-level interventions has allowed rapid evolution in the scope of population management initiatives. However, findings on the efficacy of these efforts for diabetes are mixed, and work remains to achieve the full potential of an-EHR based population approach. Here we seek to clarify definitions and key domains, provide an overview of evidence for EHR-based diabetes population management, and recommend future directions for applying the considerable power of EHRs to diabetes care and prevention.

Prediabetes: the effects on arterial thickness and stiffness in obese youth

OBJECTIVE

Adults with prediabetes are at increased risk to develop cardiovascular disease. Whether prediabetes in adolescents is associated with early markers of cardiovascular disease is not known. We sought to 1) compare the cardiovascular risk profiles among adolescents and young adults with prediabetes with those with normal glucose tolerance and 2) determine whether prediabetes is independently associated with noninvasive measures of arterial thickness and stiffness.

RESEARCH DESIGN AND METHODS

We studied 102 obese youth with prediabetes and 139 obese youth with normal glucose tolerance in a cross-sectional study. Prediabetes or at increased diabetes risk was diagnosed by a fasting blood glucose level of ≥100 to 125 mg/dL, 2-hour oral glucose tolerance test value of ≥140 to 199 mg/dL, or a hemoglobin A1c (HbA1c) value of ≥5.7% to 6.4%. Arterial thickness and stiffness were measured by carotid intima-media thickness (IMT), augmentation index, pulse wave velocity, and brachial distensibility (BrachD).

RESULTS

Nearly 50% of youth were diagnosed with prediabetes by HbA1c. Youth with prediabetes had worse metabolic profiles with higher BMI z score, systolic blood pressure, and fasting insulin; increased carotid IMT; and lower BrachD compared with normal glucose-tolerant youth (P < .05). Multivariate regression analysis found prediabetes was a significant determinant of internal carotid IMT and BrachD (P < .05). After excluding youth diagnosed by HbA1c, the prediabetes group was borderline significant for internal carotid IMT (.1 > P ≥ .05) only.

CONCLUSIONS

Youth with prediabetes have worse cardiometabolic risk factors and evidence of increased arterial thickness and stiffness. Interventions to prevent prediabetes are crucial to reduce the development of early arterial disease.

Innovative uses of electronic health records and social media for public health surveillance

Electronic health records (EHRs) and social media have the potential to enrich public health surveillance of diabetes. Clinical and patient-facing data sources for diabetes surveillance are needed given its profound public health impact, opportunity for primary and secondary prevention, persistent disparities, and requirement for self-management. Initiatives to employ data from EHRs and social media for diabetes surveillance are in their infancy. With their transformative potential come practical limitations and ethical considerations. We explore applications of EHR and social media for diabetes surveillance, limitations to approaches, and steps for moving forward in this partnership between patients, health systems, and public health.

Use of glycated hemoglobin and waist circumference for diabetic screening in women with a history of gestational diabetes

OBJECTIVE

Although their risk of type 2 diabetes is markedly increased, women with prior gestational diabetes mellitus (GDM) do not receive appropriate testing following their pregnancy. Identifying a less burdensome testing method might increase postpartum testing rates. Our objective was to examine the adequacy of glycated hemoglobin (A1C) and waist circumference (WC) measurements to detect impaired glucose metabolism among women with prior GDM.

METHODS

The analysis included 178 women who had GDM between 2003 and 2010. WC and A1C were measured, and a 75g 2h-OGTT was performed. Pre-diabetes was defined as a fasting plasma glucose (FPG) ≥ 5.6 and < 7.0 mmol/L or a 2-hour plasma glucose (2h-PG) ≥ 7.8 and < 11.0 mmol/L, and type 2 diabetes was defined as a FPG ≥ 7.0 mmol/L and/or a 2h-PG ≥ 11.1 mmol/L. Sensitivity and specificity analyses were performed.

RESULTS

The mean age of subjects was 36.4 ± 4.8 years, and testing occurred at a mean 3.5 ± 1.9 years following delivery. Combining A1C ≥ 5.7% and WC ≥ 88 cm to detect pre-diabetes had a sensitivity of 76% and specificity of 62%, and to detect type 2 diabetes it had a sensitivity of 91% and specificity of 34%. Compared with women who had A1C and WC within the normal range, women with A1C ≥ 5.7% and WC ≥ 88 cm were more likely to have type 2 diabetes (OR 4.4; 95% CI 2.0 to 9.9).

CONCLUSION

These analyses suggest that the combination of A1C and WC could represent a sensitive test for pre-diabetes and type 2 diabetes in the years following a pregnancy complicated by GDM. Further validation of this testing method is required.

Use of HbA1c for diagnoses of diabetes and prediabetes: comparison with diagnoses based on fasting and 2-hr glucose values and effects of gender, race, and age

BACKGROUND

Glycated hemoglobin (HbA1c) has been advocated for the diagnosis of diabetes and prediabetes. Its performance has been commonly assessed in corroboration with elevated fasting plasma glucose (FPG), but not the combination of FPG and 2-hr glucose values. This study assesses receiver operating characteristics (ROC) curves of HbA1c pertaining to the diagnoses of prediabetes and diabetes by FPG and/or 2-hr glucose, and the effects of age, gender, and race.

METHODS

We assessed the utility of HbA1c for diagnosing diabetes and prediabetes among 5395 adults without known diabetes from the National Health and Nutrition Examination Survey (NHANES) 2005-2010.

RESULTS

Current cutoffs of HbA1c for diabetes (6.5%) or prediabetes (5.7%) exhibited low sensitivity (0.249 and 0.354, respectively) and high specificity in identifying patients diagnosed using both FPG and 2-hr glucose, resulting in large false-negative rates (75.1% and 64.9%). Misdiagnosis rates increased with age and in non-Hispanic whites and Mexican Americans. When HbA1c was combined with FPG for diagnoses, the false-negative rate remained high for diabetes (45.7%), but was reduced for prediabetes (9.2%).

CONCLUSIONS

When assessed against diagnoses using both FPG and 2-hr glucose, HbA1c had low sensitivity and high specificity for identifying diabetes and prediabetes, which varied as a function of age and race. Regarding recently released American Diabetes Association (ADA) and joint European guidelines, it is important to consider that HbA1c values below 6.5% and 5.7% do not reliably exclude the presence of diabetes and prediabetes, respectively. Overall, the data argue for greater use of oral glucose tolerance tests (OGTTs) and both FPG and 2-hr glucose values for diagnosis of diabetes and prediabetes.

Comparing risk of new onset diabetes mellitus in chronic kidney disease patients receiving peritoneal dialysis and hemodialysis using propensity score matching

Chronic kidney disease (CKD) patients are at risk for developing new-onset diabetes mellitus (NODM) even after hemodialysis (HD) and peritoneal dialysis (PD) treatment. It is not clear if the incidence for NODM is different in CKD patients receiving HD and PD. This study compared the risk of NODM in PD patients and HD patients.

Methods

All HD and PD patients in Taiwan Renal Registry Database from 1997 to 2005 were included and all patients were followed to December 31, 2008. The risk of NODM was analyzed in PD patients and propensity score matched HD patients using logistic regression for early type NODM (< = 6 months after dialysis) and Cox regression for late type NODM (>6 months after dialysis).

Results

A total of 2548 PD patients and 10192 HD patients who had no diabetes on the initiation of dialysis were analyzed. The incidence for NODM was 3.7 per 100 patient/year for HD and 2.4 for PD patients. HD patients are more at risk for developing early type NODM (p<0.001) with an adjusted odds ratio of 1.41 [95% confidence interval (CI) 1.12–1.78)]. HD patients are more at risk for late type NODM (p<0.001) with an adjusted hazard ratio of 2.01 (95% CI: 1.77–2.29). Patient’s age was negatively associated with risk of early type of NODM (p<0.001) but positively associated with risk of late type NODM (p<0.001).

Conclusions

Chronic kidney disease patients receiving hemodialysis are more at risk for developing new-onset diabetes mellitus compared to those receiving peritoneal dialysis.

Insulin sensitivity, and β-cell function in relation to hemoglobin A1C

BACKGROUND AND AIMS

The A1C diagnostic criterion for identifying individuals at increased risk for diabetes, introduced by the American Diabetes Association in 2010, was not defined on the basis of the principal pathophysiological abnormalities responsible for the development and progression of type 2 diabetes; we therefore wished to gain a deeper insight into the metabolic abnormalities characterizing the group of at risk individuals with an A1C value of 5.7-6.4%.

METHODS AND RESULTS

As many as 338 non-diabetic offspring of type 2 diabetic patients were consecutively recruited. Insulin secretion was assessed using both indexes derived from oral glucose tolerance test (OGTT), and intravenous glucose tolerance test (IVGTT). Insulin sensitivity was measured by hyperinsulinemic euglycemic clamp. As compared with subjects with A1C <5.7%, individuals with A1C of 5.7-6.4% exhibited lower insulin sensitivity after adjusting for age, gender and body mass index (BMI). Insulin secretion estimated from the OGTT, did not differ between the two groups. By contrast, as compared with subjects with A1C <5.7%, the acute insulin response (AIR) during an IVGTT and both IVGTT-derived and OGTT-derived disposition indexes were reduced in individuals with A1C of 5.7-6.4% after adjusting for age, gender and BMI. As A1C increased to ≥ 5.7%, a sharp decrease in insulin sensitivity and β-cell function, measured as disposition index, was observed.

CONCLUSIONS

Caucasian individuals with A1C ≥ 5.7% exhibit both core pathophysiological defects of type 2 diabetes i.e. insulin resistance and β-cell dysfunction.

Hemoglobin A1c as a marker for identifying diabetes and cardiovascular risk factors: the China Health and Nutrition Survey 2009

Hemoglobin A1c (HbA1c) has been recommended as an optional method for diagnosing diabetes. The impact of HbA1c on the diagnosis of diabetes has not been evaluated in China, a country with the greatest number of people with diabetes in the world. Hence, we aim to examine how well HbA1c performs as compared with fasting plasma glucose (FPG) for diagnosing diabetes in Chinese population. We conducted a cross-sectional analysis of 7,641 Chinese men and women aged ≥18 years using data from the China Health and Nutrition Survey 2009 in which FPG and standardized HbA1c were measured. HbA1c was measured with high-performance liquid chromatography system. Diabetes is defined as having FPG ≥7 mmol/l or HbA1c ≥6.5 %. Overall, 5.0 and 5.8 % had undiagnosed diabetes by FPG ≥7 mmol/l and HbA1c ≥6.5 %, respectively. Overlap between HbA1c- and FPG-based diagnosis of diabetes was limited (n = 214, 34.9 %). Similar trends were noted in both genders, all age groups, urban/rural settings, regions, body mass index (BMI) categories, waist circumference (WC) groups, and blood pressure status. Solely HbA1c-defined individuals exhibited higher levels of BMI, WC, total cholesterol, and hypersensitive C-reactive protein and lower levels of homeostasis model assessment of insulin resistance. We note limited overlap between FPG- and HbA1c-based diagnosis of diabetes. The limited overlap between FPG- and HbA1c-based diagnosis of diabetes persisted in each evaluated subgroup. HbA1c criterion for the diagnosis of diabetes identifies individuals with a worse cardiovascular risk profile compared with FPG.

Community screening for pre-diabetes and diabetes using HbA1c levels in high-risk African Americans and Latinos

OBJECTIVE

To evaluate community screening using HbA1c levels in high risk African Americans and Latinos in those not known to have diabetes.

DESIGN

HbA1c levels were measured in 1542 African Americans and Latinos aged > or = 40 years with one or more of the following risk factors: family history in first degree relatives, waist circumference > or = 40 inches in males or > or = 35 inches in females, and hypertension, either treatment for or a measured BP of > or = 140/ 90 mm Hg. Oral glucose tolerance tests (OGTT) were offered to those meeting the HbA1c criterion for pre-diabetes.

SETTING

Churches, community health fares, senior citizen sites.

PARTICIPANTS

People without known diabetes.

MAIN OUTCOME MEASURES

Proportion of people meeting the HbA1c criteria for prediabetes (5.8-6.4%) and diabetes (> or = 6.5%).

RESULTS

32% had one, 50% had two and 18% had three risk factors. By HbA1c criteria, 40% had pre-diabetes and 25% had diabetes. Increased waist circumference was the most common risk factor followed by a positive family history, and lastly, hypertension. Each individual risk factor was significantly (P < .001) and progressively more common as glycemia increased. Each additional risk factor increased the odds of pre-diabetes or diabetes by 2- to 4-fold. In individuals with pre-diabetes who underwent an OGTT, 59% were normal, 35% had pre-diabetes and only 6% had diabetes.

CONCLUSIONS

Community screening of high risk African Americans and Latinos with HbA1c levels identifies a large proportion of people with pre-diabetes and diabetes. Those identified with pre-diabetes are unlikely to meet the OGTT criteria for diabetes.