HbA(1c) as a screening tool for detection of Type 2 diabetes: a systematic review

Controversies on how diabetes is diagnosed

PURPOSE OF REVIEW

To evaluate the controversial aspects of diabetes diagnosis.

RECENT FINDINGS

Within the past 2 years, revised guidelines for the diagnosis of diabetes have been issued which endorse the use of the hemoglobin A1C as a diagnostic test, in addition to the previously recommended tests. Updated diagnostic criteria for gestational diabetes were also published in the same period. Recent publications on the current role of oral glucose tolerance tests and diagnosis of diabetes in the acutely ill are sparse. There are new recommendations regarding the use of genetic testing and antibody testing in establishing the cause of diabetes.

SUMMARY

The inclusion of A1C as a diagnostic test has many advantages including reproducibility of the test and convenience, but there are situations where the test is unreliable and it misses many individuals who would have been diagnosed by plasma glucose testing. The diagnostic threshold of 6.5% for the A1C remains controversial. There is still no consensus on the best approach to diagnose gestational diabetes. The role of the oral glucose tolerance test seems to be diminishing. Diagnosis of diabetes in acute illness is aided by A1C testing. Genetic and autoantibody testing in specific situations offer diagnostic and therapeutic utility.

Hemoglobin A1c and glucose criteria identify different subjects as having type 2 diabetes in middle-aged and older populations: the KORA S4/F4 Study

OBJECTIVE

The American Diabetes Association (ADA) has recently recommended HbA1c for diagnosing diabetes as an alternative to glucose-based criteria. We compared the new HbA1c-based criteria for diagnosis of diabetes and prediabetes with the glucose-based criteria.

RESEARCH DESIGN AND METHODS

In the population-based German KORA surveys (S4/F4) 1,764 non-diabetic participants aged 31-60 years and 896 participants aged 61-75 years underwent measurements of HbA1c, fasting plasma glucose (FPG), and 2-h glucose.

RESULTS

Only 20% of all subjects diagnosed with diabetes by glucose or HbA1c criteria had diabetes by both criteria; for prediabetes, the corresponding figure was 23%. Using HbA1c ≥ 6.5%, the prevalence of diabetes was strongly reduced compared to the glucose criteria (0.7% instead of 2.3% in the middle-aged, 2.9% instead of 7.9% in the older subjects). Only 32.0% (middle-aged) and 43.2% (older group) of isolated impaired glucose tolerance (i-IGT) cases were detected by the HbA1c criterion (5.7% ≤ HbA1c < 6.5%).

CONCLUSION

By glucose and the new HbA1c diabetes criteria, different subjects are diagnosed with type 2 diabetes in middle-aged as well as older subjects. The new HbA1c criterion lacks sensitivity for impaired glucose tolerance.

Validity of glycated hemoglobin in screening and diagnosing type 2 diabetes mellitus in Chinese subjects

BACKGROUND/AIMS

The application of glycated hemoglobin (HbA(1c)) for the diagnosis of diabetes is currently under extensive discussion. In this study, we explored the validity of using HbA(1c) as a screening and diagnostic test in Chinese subjects recruited in Nanjing, China.

METHODS

In total, 497 subjects (361 men and 136 women) with fasting plasma glucose (PG) ≥ 5.6 mmol/L were recruited to undergo the oral glucose tolerance test (OGTT) and HbA(1c) test. Plasma lipid, uric acid, and blood pressure were also measured.

RESULTS

Using a receiver operating characteristic curve, the optimal cutoff point of HbA(1c) related to diabetes diagnosed by the OGTT was 6.3%, with a sensitivity and specificity of 79.6% and 82.2%, respectively, and the area under the curve was 0.87 (95% confidence interval, 0.83 to 0.92). A HbA(1c) level of 6.5% had a sensitivity and specificity of 62.7% and 93.5%, respectively. When comparing the HbA(1c) ≥ 6.5% or OGTT methods for diagnosing diabetes, the former group had significantly higher HbA(1c) levels and lower levels of fasting and 2-hour PG than the latter group. No significant difference was observed in the other metabolism indexes between the two groups.

CONCLUSIONS

Our results suggest that HbA(1c) ≥ 6.5% has reasonably good specificity for diagnosing diabetes in Chinese subjects, which is in concordance with the American Diabetes Association recommendations.

Ischemia-modified albumin in type 2 diabetic patients with and without peripheral arterial disease

OBJECTIVE:

To determine whether there is an association between serum ischemia-modified albumin and the risk factor profile in type 2 diabetic patients with peripheral arterial disease and to identify the risk markers for peripheral arterial disease.

METHODS:

Participants included 290 patients (35.2% women) with type 2 diabetes. The ankle-brachial pressure index was measured using a standard protocol, and peripheral arterial disease was defined as an ankle-brachial index <0.90 or ≥1.3. The basal ischemia-modified albumin levels and clinical parameters were measured and analyzed. The risk factors for peripheral arterial disease were examined by multiple logistic analyses.

RESULTS:

Age, systolic blood pressure, total cholesterol, low-density lipoprotein cholesterol, urine albumin, homocysteine, and ischemia-modified albumin were significantly higher in patients with peripheral arterial disease than in disease-free patients (p<0.05), while ankle-brachial index was lower in the former group (p<0.05). Ischemia-modified albumin was positively associated with HbA1c and homocysteine levels (r = 0.220, p = 0.030; r = 0.446, p = 0.044, respectively), while no correlation was found with ankle-brachial index. Multiple logistic analyses indicated that HbA1c, systolic blood pressure, homocysteine and ischemia-modified albumin were independent risk factors for peripheral arterial disease in the diabetic subjects.

CONCLUSION:

The baseline ischemia-modified albumin levels were significantly higher and positively associated with HbA1c and homocysteine levels in type 2 diabetic patients with peripheral arterial disease. Ischemia-modified albumin was a risk marker for peripheral arterial disease. Taken together, these results might be helpful for monitoring diabetic peripheral arterial disease.

The Heritability of HbA1c and Fasting Blood Glucose in Different Measurement Settings

In an extended twin study we estimated the heritability of fasting HbA1c and blood glucose levels. Blood glucose was assessed in different settings (at home and in the clinic). We tested whether the genetic factors influencing fasting blood glucose levels overlapped with those influencing HbA1c and whether the same genetic factors were expressed across different settings. Fasting blood glucose was measured at home and during two visits to the clinic in 77 healthy families with same-sex twins and siblings, aged 20 to 45 years. HbA1c was measured during the first clinic visit. A 4-variate genetic structural equation model was used that estimated the heritability of each trait and the genetic correlations among traits. Heritability explained 75% of the variance in HbA1c. The heritability of fasting blood glucose was estimated at 66% at home and lower in the clinic (57% and 38%). Fasting blood glucose levels were significantly correlated across settings (0.34 <r< 0.54), mostly due to a common set of genes that explained between 53% and 95% of these correlations. Correlations between HbA1c and fasting blood glucoses were low (0.11 <r< 0.23) and genetic factors influencing HbA1c and fasting glucose were uncorrelated. These results suggest that in healthy adults the genes influencing HbA1c and fasting blood glucose reflect different aspects of the glucose metabolism. As a consequence these two glycemic parameters can not be used interchangeably in diagnostic procedures or in studies attempting to find genes for diabetes. Both contribute unique (genetic) information.

Brachial blood pressure-independent relations between radial late systolic shoulder-derived aortic pressures and target organ changes

Central aortic blood pressure (BP; BPc) predicts outcomes beyond brachial BP. In this regard, the application of a generalized transfer function (GTF) to radial pulse waves for the derivation of BPc is an easy and reproducible measurement technique. However, the use of the GTF may not be appropriate in all circumstances. Although the peak of the second shoulder of the radial waveform (P2) is closely associated with BPc, and, hence, BPc may be assessed without the need for a GTF, whether P2-derived BPc is associated with adverse cardiovascular changes independent of brachial BP is uncertain. Thus, P2- and GTF-derived aortic BPs were assessed using applanation tonometry and SphygmoCor software. Left ventricular mass was indexed for height(1.7) (n=678) and carotid intima-media thickness (IMT; n=462) was determined using echocardiography and vascular ultrasound. With adjustments for nurse-derived brachial pulse pressure (PP), P2-derived central PP was independently associated with left ventricular mass indexed for height(1.7) (partial r=0.18; P<0.0001) and IMT (partial r=0.40; P<0.0001). These relations were similar to nurse-derived brachial PP-independent relations between GTF-derived central PP and target organ changes (left ventricular mass indexed for height(1.7): partial r=0.17, P<0.0001; IMT: partial r=0.37, P<0.0001). In contrast, with adjustments for central PP, nurse-derived brachial PP-target organ relations were eliminated (partial r=-0.21 to 0.05). Twenty-four-hour, day, and night PP-target organ relations did not survive adjustments for nurse-derived brachial BP. In conclusion, central PP derived from P2, which does not require a GTF, is associated with cardiovascular target organ changes independent of brachial BP. Thus, when assessing adverse cardiovascular effects of aortic BP independent of brachial BP, P2-derived measures may complement GTF-derived measures of aortic BP.

Role of HbA1c in the Screening of Diabetes Mellitus in a Korean Rural Community

BACKGROUND

Recently, the measurement of glycated hemoglobin (HbA1c) was recommended as an alternative to fasting plasma glucose or oral glucose tolerance tests for diagnosing diabetes mellitus (DM). In this study, we analyzed HbA1c levels for diabetes mellitus screening in a Korean rural population.

METHODS

We analyzed data from 10,111 subjects from a Korean Rural Genomic Cohort study and generated a receiver operating characteristic curve to determine an appropriate HbA1c cutoff value for diabetes.

RESULTS

The mean age of the subjects was 56.3±8.1 years. Fasting plasma glucose and 2-hour plasma glucose after 75 g oral glucose tolerance tests were 97.5±25.6 and 138.3±67.1 mg/dL, respectively. The mean HbA1c level of the subjects was 5.7±0.9%. There were 8,809 non-DM patients (87.1%) and 1,302 DM patients (12.9%). A positive relationship between HbA1c and plasma glucose levels and between HbA1c and 2-hour plasma glucose levels after oral glucose tolerance tests was found in a scatter plot of the data. Using Youden's index, the proper cutoff level of HbA1c for diabetes mellitus screening was 5.95% (sensitivity, 77%; specificity, 89.4%).

CONCLUSION

Our results suggest that the optimal HbA1c level for DM screening is 5.95%.

Gastroesophageal reflux disease is inversely related with glycemic control in morbidly obese patients

BACKGROUND

The link between diabetes mellitus and gastroesophageal reflux disease (GERD) is controversial. We assessed the relationship between glycemic control (GC) and GERD in morbidly obese patients.

METHODS

Consecutive patients with morbid obesity (n = 86) underwent manometry, pH-metry, endoscopy, and contrasted X-ray after responding to a GERD questionnaire and dosing fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c). Patients with poor GC (HbA1c, 6.1-10% and FPG < 140 mg/dl) and those with very poor GC (HbA1c > 10% or FPG > 140 mg/dl) were compared.

RESULTS

There were 63 patients with poor GC and 17 with very poor GC. Compared to patients with very poor GC, patients with poor GC showed higher heartburn scores [8 (0-12) vs. 0 (0-4); P = 0.003]; higher total esophageal acid exposure [5.2% (2.5-10.5%) vs. 2.3% (0.8-7.5%); P = 0.041]; lower distal esophageal amplitude (105 ± 38 vs. 134 ± 63 mmHg; P = 0.019); higher expiratory gastroesophageal pressure gradient (GEPG, 7 ± 3.4 vs. 5.2 ± 3 mmHg; P = 0.050); lower ventilatory gradient (inspiratory-expiratory GEPG, 10.9 ± 3.8 vs. 13.6 ± 4.1 mmHg; P = 0.012); lower waist-to-hip ratio (0.95 vs. 1; P = 0.040); and more hiatal hernia (38% vs. 6%; P = 0.016).

CONCLUSIONS

This study suggests an inverse relation between glycemic control and GERD in morbidly obese patients. This can be partially explained by a lower frequency of hiatal hernia in patients with very poor glycemic control.

Type 2 diabetes affects hippocampus volume differentially in men and women

BACKGROUND

Type 2 diabetes mellitus (T2DM) has been shown to result in medical complications on several organ systems including the kidneys, eyes, cardiovascular system, and most recently described the brain, including the hippocampus. There is also evidence that females are disproportionately affected by these medical complications. Brain volume reductions have also been associated with chronic low-grade inflammation and dyslipidaemia. This study investigated the relationships among T2DM, gender, inflammation, dyslipidaemia, and hippocampal volumes.

METHOD

Participant groups consisted of 40 obese adults with T2DM and 47 lean adults, group-matched on age, gender, race, and education. Each participant underwent medical examination including a standard panel of blood tests, a magnetic resonance imaging, and cognitive evaluation.

RESULTS

We show that there is a gender difference in the association of T2DM and hippocampal volumes: diabetic women are most affected despite having better glucose control than their male counterparts. Although females with T2DM had disproportionately lower high density lipoprotein as well as better haemoglobin A1c, neither of these results explained why females with T2DM had the smallest hippocampal volumes.

CONCLUSIONS

These important findings indicate that in addition to the higher rate of traditional medical complication, females with T2DM are likely to suffer more brain complications than males. These observations, if supported by larger studies, suggest that in the future gender could be considered when customizing diabetes treatment.

Predictive value of HbA1c for incident diabetes among subjects with impaired glucose tolerance--analysis of the Indian Diabetes Prevention Programmes

AIMS

The objectives of the study were to assess the predictive value of baseline HbA(1c) for incident diabetes among the participants with impaired glucose tolerance in the Indian Diabetes Prevention Programmes 1 and 2.

METHODS

Data at baseline and at 3-year follow-up were analysed in combined cohorts of the Indian Diabetes Prevention Programmes 1 and 2. Within the 3 years, 324 of the 845 participants developed diabetes (World Health Organization criteria). The predictive value of baseline HbA(1c) for incident diabetes was determined by logistic regression analysis.

RESULTS

Baseline HbA(1c) values had heterogenous distribution. The distribution was similar in isolated impaired glucose tolerance or in impaired glucose tolerance in combination with impaired fasting glucose. A progressive increase in diabetes occurred with increasing HbA(1c). HbA(1c) showed the strongest association with incident diabetes in the multiple logistic regression analysis (odds ratio 3.548, P < 0.0001). The cut-off HbA(1c) of 43 mmol/mol (6.05%) had 67% sensitivity and 60% specificity to predict future diabetes. The diagnostic sensitivity of HbA(1c) of ≥ 48 mmol/mol (≥ 6.5%) was only 51%, with a specificity of 87%, when compared with the oral glucose tolerance glucose values.

CONCLUSIONS

Baseline HbA(1c) was highly predictive of future diabetes in Asian Indian subjects with impaired glucose tolerance and nearly 60% of the incidence occurred with values ≥ 42 mmol/mol (≥ 6.0). Diagnostic sensitivity of HbA(1c) ≥ 48 mmol/mol (≥ 6.5%) for new diabetes was only 51% using the oral glucose tolerance test as the standard for comparison.

Glycated hemoglobin, diabetes mellitus, and cardiovascular risk in a cross-sectional study among She Chinese population

OBJECTIVE

To determine whether glycated hemoglobin (HbA1c) could be used to diagnose Type 2 diabetes mellitus in She Chinese People and to assess the role of HbA1c in the development of cardiovascular disease.

RESEARCH DESIGN AND METHODS

An ethnically representative sample of 687 (277 males and 410 females) adults, 20 yr of age or older participated in the study, and 75-g oral glucose tolerance test was administrated. Based on receiver operating characteristic curves, various cut-off values of HbA1c were used to stratify glucose tolerance. Several indexes were used to assess the cardiovascular risk, including estimated glomerular filtration rate (eGFR), Tpeak-end, Tp-e dispersion, aVL R wave, and QTc.

RESULTS

Using World Health Organization as gold standard, the HbA1c value of 6.9% was optimal to diagnose diabetes mellitus with a sensitivity of 35.3% and specificity of 94.0%. And for impaired fasting glucose, impaired glucose tolerance, and impaired glucose regulation, the cut-off points were all 6.1%. Assessed by logistic regression model, HbA1c was an independent risk factor for the decline in eGFR; R wave in lead aVL increased significantly (p<0.05) with the increase of HbA1c values. Other indexes reflecting the cardiovascular risks were not meaningful in our study.

CONCLUSIONS

HbA1c may be not a preferred method to diagnose Type2 diabetes in She Chinese people. However, more attention should be paid to subjects with HbA1c>6.1%, and their blood glucose should be tightly measured in clinical practice. In addition, we suggest that HbA1c is a predictor of cardiovascular disease.

Hemoglobin A1c as a diagnostic tool: public health implications from an actor-network perspective

Public health arguments for collecting hemoglobin A1c (HbA1c) data, particularly in clinical settings, should be reframed to place more emphasis on nonmedical determinants of population health. We compare individual- with population-level interpretations of HbA1c titers. This comparison reveals that public health researchers need to pay close attention to diagnostic tests and their uses, including rhetorical uses. We also synthesize historical and current evidence to map out 2 possible scenarios for the future. In the first scenario, prevention efforts emphasize primary care and focus almost entirely downstream. The second scenario anticipates downstream interventions but also upstream interventions targeting environments. Our analysis adapts actor-network theory to strategic planning and forecasting in public health.

The worldwide epidemiology of type 2 diabetes mellitus--present and future perspectives

Over the past three decades, the number of people with diabetes mellitus has more than doubled globally, making it one of the most important public health challenges to all nations. Type 2 diabetes mellitus (T2DM) and prediabetes are increasingly observed among children, adolescents and younger adults. The causes of the epidemic of T2DM are embedded in a very complex group of genetic and epigenetic systems interacting within an equally complex societal framework that determines behavior and environmental influences. This complexity is reflected in the diverse topics discussed in this Review. In the past few years considerable emphasis has been placed on the effect of the intrauterine environment in the epidemic of T2DM, particularly in the early onset of T2DM and obesity. Prevention of T2DM is a 'whole-of-life' task and requires an integrated approach operating from the origin of the disease. Future research is necessary to better understand the potential role of remaining factors, such as genetic predisposition and maternal environment, to help shape prevention programs. The potential effect on global diabetes surveillance of using HbA(1c) rather than glucose values in the diagnosis of T2DM is also discussed.

Improvement of diabetes care in a small but geographically widely spread population in Greenland. Effects of a national diabetes care programme

AIMS

To estimate the prevalence of diagnosed Type 2 diabetes mellitus in Greenland and to evaluate the quality of the diabetes care before and after implementation of a new diabetes programme.

METHODS

In this observational and cross-sectional study, data from the medical records were collected in Greenland in 2008 and 2010. Information about age, gender, most recently measured HbA(1c) , blood pressure and serum cholesterol and from the examination of eyes, feet and urine was obtained. The prevalence was estimated using the whole adult population in Greenland as background population. The quality of the diabetes care was monitored by six process, three biological and three treatment indicators. A diabetes concept based on national guidelines, systematized recording in an electronic medical record and feedback to the clinics were used to improve diabetes care.

RESULTS

Four hundred and sixty-five patients were included in the 2008 sample and 691 in the 2010 sample. The total prevalence increased from 2.3 (95% CI 2.1-2.5) % in 2008 to 2.7 (95%CI 2.5-3.0) among Greenlanders aged 40 years old or above, corresponding to an increase of 19% (P = 0.006). All process indicators improved significantly between the two observations.

CONCLUSIONS

Along with an increasing prevalence of diagnosed Type 2 diabetes, all six process quality indicators increased. It is strongly recommended that focus on the quality of diabetes care in Greenland should be maintained in order to benefit from the programme in the longer term.

Discordance between HbA1c and fasting plasma glucose criteria for diabetes screening is associated with obesity and old age in Korean individuals

We evaluated the agreement between HbA1c- and FPG-based criteria for screening of diabetes in an asymptomatic Korean population and identified independent factors associated with discordance. The discordance between the two diabetic criteria was significantly associated with obesity and older age.

Diabetes screening with hemoglobin A1c prior to a change in guideline recommendations: prevalence and patient characteristics

BACKGROUND

In January 2010, the American Diabetes Association recommended the use of hemoglobin A1c (Hgb A1c) to screen and diagnose diabetes. This study explored the prevalence and clinical context of Hgb A1c tests done for non-diabetic primary care patients for the three years prior to the release of the new guidelines. We sought to determine the provision of tests in non-diabetic patients age 19 or over, patients age 45 and over (eligible for routine diabetes screening), the annual change in the rate of this screening test, and the patient characteristics associated with the provision of Hgb A1c screening.

METHODS

We conducted a retrospective study using data routinely collected in Electronic Medical Records. The participants were thirteen community-based family physicians in Toronto, Ontario. We calculated the proportion of non diabetic patients who had at least one Hbg A1c done in three years. We used logistic generalized estimating equation with year treated as a continuous variable to test for a non-zero slope in yearly Hbg A1c provision. We modelled screening using multivariable logistic regression.

RESULTS

There were 11,792 non-diabetic adults. Of these, 1,678 (14.2%; 95%CI 13.6%-14.9%) had at least one Hgb A1c test done; this was higher for patients 45 years of age or older (20.2%; 95% CI 19.3% - 21.2%). The proportion of non-diabetic patients with an A1c test increased from 5.2% in 2007 to 8.8% in 2009 (p < 0.0001 for presence of slope). Factors associated with significantly greater adjusted odds ratios of having the test done included increasing diastolic blood pressure, increasing fasting glucose, increasing body mass index, increasing age, as well as male gender and presence of hypertension, but not smoking status or LDL cholesterol. Patients living in the highest income quintile neighbourhoods had significantly lower odds ratios of having this test done than those in the lowest quintile (p < 0.001).

CONCLUSIONS

A large and increasing proportion of the non-diabetic patients we studied have had an Hgb A1c for screening prior to guidelines recommending the test for this purpose. Several risk factors for cardiovascular disease or diabetes were associated with the provision of the Hgb A1c. Early uptake of the test may represent appropriate utilization.

Does vertebral bone marrow fat content correlate with abdominal adipose tissue, lumbar spine bone mineral density, and blood biomarkers in women with type 2 diabetes mellitus?

PURPOSE

To compare vertebral bone marrow fat content quantified with proton MR spectroscopy ((1)H-MRS) with the volume of abdominal adipose tissue, lumbar spine volumetric bone mineral density (vBMD), and blood biomarkers in postmenopausal women with and without type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Thirteen postmenopausal women with T2DM and 13 age- and body mass index-matched healthy controls were included in this study. All subjects underwent (1)H-MRS of L1-L3 to quantify vertebral bone marrow fat content (FC) and unsaturated lipid fraction (ULF). Quantitative computed tomography (QCT) was performed to assess vBMD of L1-L3. The volumes of abdominal subcutaneous/visceral/total adipose tissue were determined from the QCT images and adjusted for abdominal body volume (SAT(adj)/VAT(adj)/TAT(adj)). Fasting blood tests included plasma glucose and HbA1c.

RESULTS

Mean FC showed an inverse correlation with vBMD (r = -0.452; P < 0.05) in the whole study population. While mean FC was similar in the diabetic women and healthy controls (69.3 ± 7.5% versus 67.5 ± 6.1%; P > 0.05), mean ULF was significantly lower in the diabetic group (6.7 ± 1.0% versus 7.9 ± 1.6%; P < 0.05). SAT(adj) and TAT(adj) correlated significantly with mean FC in the whole study population (r = 0.538 and r = 0.466; P < 0.05). In contrast to the control group, significant correlations of mean FC with VAT(adj) and HbA1c were observed in the diabetic group (r = 0.642 and r = 0.825; P < 0.05).

CONCLUSION

This study demonstrated that vertebral bone marrow fat content correlates significantly with SAT(adj), TAT(adj), and lumbar spine vBMD in postmenopausal women with and without T2DM, but with VAT(adj) and HbA1c only in women with T2DM.

HbA1c of 6.5% to diagnose diabetes mellitus -- does it work for us? -- the Bellville South Africa study

Background

HbA1c has been the gold standard for glycaemic control follow-up for decades. In 2009, a level of 6.5% (48 mmol/mol) was proposed as diagnostic for diabetes. We test this cut-off in our community.

Methods

Participants (946) from a community-based study were screened for diabetes using either a fasting blood glucose or oral glucose tolerance test (OFTT). The HbA1c cut-off of 6.5% was tested for each group. A receiver operator characteristic (ROC) curve for both groups was generated to establish an optimal cut-off.

Results

Our study included 224 (23.7%) males and 722 (76.3%) females. Using fasting blood glucose alone, 117 (14%) were diagnosed with diabetes −50% had an HbA1c value of ≥6.5% (48 mmol/mol). Using an OGTT, 147 (18%) were diagnosed with diabetes −46% had an HbA1c value of ≥6.5% (48 mmol/mol). ROC curves found a level of 6.1% (43 mmol/mol) to be optimal in both groups (AUC 0.85 and 0.82 respectively). The sensitivities were 80% and 75% and the specificities 77% and 78% respectively.

Conclusions

A cut off of 6.5% (48 mmol/mol) is a good diagnostic tool with its high specificity; however the low sensitivity limits its use. We found a level of 6.1% (43 mmol/mol) to be optimal. This emphasizes the need for evidenced based values to be established in various population groups.

Aldosterone-to-renin ratio and the relationship between urinary salt excretion and blood pressure in a community of African ancestry

BACKGROUND

Although aldosterone influences the effect of salt intake on blood pressure (BP), the extent to which this occurs at a population level is uncertain. We therefore aimed to determine, at a community level in a group of African descent, whether in the absence of primary aldosteronism, the relationship between salt intake and BP is modified by circulating aldosterone, and the extent to which this occurs.

METHODS

In 575 participants of African ancestry (age >16 years), we assessed whether aldosterone-to-renin ratio (ARR) is associated with the relationship between urinary sodium (Na(+))-to-potassium (K(+)) ratio (urinary Na(+)/K(+)) (from 24-h urine samples), an index of salt intake, and BP.

RESULTS

With adjustments for confounders, interactions between ARR and urinary Na(+)/K(+) were independently associated with systolic BP (SBP) (P < 0.0001), an effect that was accounted for by interactions between serum aldosterone concentrations and urinary Na(+)/K(+) (P < 0.0001), but not between plasma renin concentrations and urinary Na(+)/K(+) (P = 0.52). The interaction between ARR and urinary Na(+)/K(+) translated into a marked difference in the relationship between urinary Na(+)/K(+) and SBP in participants above compared to below the median for ARR (effect of 1 s.d. increase in urinary Na(+)/K(+) on SBP: ARR > median = 4.2 ± 0.6 mm Hg; ARR < median = 1.2 ± 0.4 mm Hg, P < 0.0001). In addition, participants with urinary Na(+)/K(+) above the median had higher multivariate-adjusted SBP (P < 0.001) only if ARR was also above the median.

CONCLUSIONS

In groups of African descent, in the absence of primary aldosteronism, an increased aldosterone concentration relative to renin modifies a substantial proportion of the relationship between urinary Na(+)/K(+) and BP at a community level.

Relationship of predominantly mild current smoking to out-of-office blood pressure in a community sample in Africa

OBJECTIVES

As the impact of mild smoking on blood pressure (BP) is uncertain, we assessed the relationship between predominantly mild current smoking and out-of-office BP and the effect of angiotensin-converting enzyme (ACE) genotype on this relationship in a community sample of black African ancestry.

METHODS

In 689 participants randomly recruited from an urban, developing community of black African descent, we assessed smoking habits, out-of-office (24-h), and in-office conventional and central (applanation tonometry) BP, and ACE insertion (I)/deletion (D) variant genotype.

RESULTS

A total of 14.5% (n=100) were current smokers, the majority being mild (72%, 7.4 ± 4.6 cigarettes/day). Despite current smokers having only modest increases in in-office (P<0.05) and similar central aortic BP values as nonsmokers, current smokers had higher unadjusted (P<0.005-P<0.0005) and multivariate adjusted 24-h SBP/DBP (mmHg; smokers=123 ± 15/76 ± 10; nonsmokers=118 ± 14/72 ± 9; P<0.005-P<0.0005) than nonsmokers, effects that were DD genotype-dependent (P<0.005 for interaction) and replicated in sex-specific groups, nondrinkers, and in overweight and obese. Current smoking was second only to age in the quantitative impact on 24-h DBP. Smoking 4.6 cigarettes per day (one standard deviation) translated into increases in 24-h SBP (mmHg) of 2.12 [confidence interval (CI)=1.77-2.47] in all participants and 3.62 (CI=3.13-4.12) in participants with the DD genotype. The risk of uncontrolled 24-h BP was increased in smokers as compared to nonsmokers (adjusted odds ratio=1.87, CI=1.02-3.41, P<0.05), an effect that was enhanced in participants with the DD genotype (adjusted odds ratio=4.01, CI=1.59-10.09, P<0.005).

CONCLUSION

Mild current smoking is independently associated with an appreciable proportion of out-of-office BP in a black African community, an effect that is ACE genotype-dependent.

HbA(1c) values for defining diabetes and impaired fasting glucose in Asian Indians

AIM

To determine the glycosylated haemoglobin (HbA(1c)) cut-points for diabetes and impaired fasting glucose (IFG) among Asian Indians.

METHODS

Participants (n=525) were a random sample selected from the India Health Study. Based on history and fasting plasma glucose (FPG), participants were classified into known diabetes, newly diagnosed diabetes (NDD), impaired fasting glucose (IFG) [ADA and WHO criteria] or normal fasting glucose (NFG). Receiver Operating Characteristic curves were used to identify the optimum sensitivity and specificity for defining HbA(1c) cut-points for NDD and IFG against the FPG criteria.

RESULTS

There were 64 participants with a known history of diabetes. Of the remaining 461, IFG was present in 44.7% (ADA) and 18.2% (WHO), and 10.4% were NDD. Mean HbA(1c) were 5.4 (±0.04)% for NFG; 5.7 (±0.06)% among IFG-ADA, 5.8 (±0.09)% among IFG-WHO; 7.5 (±0.33)% for NDD and 8.4 (±0.32)% for known diabetes. Optimal HbA(1c) cut-point for NDD was 5.8% (sensitivity=75%, specificity=75.5%, AUC=0.819). Cut-point for IFG (ADA) was 5.5% (sensitivity=59.7%, specificity=59.9%, AUC=0.628) and for IFG (WHO) was 5.6% (sensitivity=60.7%, specificity=65.1%, AUC=0.671).

CONCLUSION

In this study population from north and south regions of India, the HbA(1c) cut-point that defines NDD (≥5.8%) was much lower than that proposed by an international expert committee and the American Diabetes Association (≥6.5%). A cut-point of ≥5.5% or ≥5.6% defined IFG, and was slightly lower than the ≥5.7% for high risk proposed, but accuracy was less than 70%.

Marked underestimation of blood pressure control with conventional vs. ambulatory measurements in an urban, developing community of African ancestry

BACKGROUND

As groups of African descent may have higher nocturnal blood pressure (BP) for a given day BP than other ethnic groups, we ascertained whether this translates into differences in conventional (CBP) and 24-h ambulatory (ABP) BP control at a community level.

METHODS

Ambulatory 24-h, day and night BP (model 90207; SpaceLabs, Issaquah, WA) and CBP (mean of five values) control rates were determined in 689 randomly selected participants (>16 years) of African ancestry in South Africa. Target organ effects were determined from urinary microalbumin-to-creatinine ratios (ACR) and aortic pulse wave velocity (PWV, applanation tonometry).

RESULTS

Of the participants 45.7% were hypertensive and 22.6% were receiving antihypertensive medication. More participants had uncontrolled BP at night (34.0%) than during the day (22.6%, P < 0.0001). Uncontrolled CBP was noted in 37.2% of participants, while a much lower proportion had uncontrolled ABP (24.1%) (P < 0.0001). Marked differences in the proportion of hypertensive participants with uncontrolled CBP and ABP were noted (treated: CBP = 62.2%, ABP = 33.3%, P < 0.0001; all: CBP = 81.3%, ABP = 44.4%, P < 0.0001). These differences were accounted for by a high prevalence of isolated increases in CBP (white-coat effects) (treated = 35.9%; all = 39.4%). Indeed, after censoring data from participants with white-coat effects, similar CBP and ABP control rates were noted. Participants with white-coat effects had similar ACR and PWV values as participants with normal ABP and CBP.

CONCLUSIONS

In communities of African descent, despite worse BP control at night than during the day, a high prevalence of white-coat effects translates into a striking underestimation of BP control in hypertensives when employing CBP rather than ABP measurements.

Utility of hemoglobin A(1c) for diagnosing prediabetes and diabetes in obese children and adolescents

OBJECTIVE

Hemoglobin A(1c) (A1C) has emerged as a recommended diagnostic tool for identifying diabetes and subjects at risk for the disease. This recommendation is based on data in adults showing the relationship between A1C with future development of diabetes and microvascular complications. However, studies in the pediatric population are lacking.

RESEARCH DESIGN AND METHODS

We studied a multiethnic cohort of 1,156 obese children and adolescents without a diagnosis of diabetes (male, 40%/female, 60%). All subjects underwent an oral glucose tolerance test (OGTT) and A1C measurement. These tests were repeated after a follow-up time of ∼2 years in 218 subjects.

RESULTS

At baseline, subjects were stratified according to A1C categories: 77% with normal glucose tolerance (A1C <5.7%), 21% at risk for diabetes (A1C 5.7-6.4%), and 1% with diabetes (A1C >6.5%). In the at risk for diabetes category, 47% were classified with prediabetes or diabetes, and in the diabetes category, 62% were classified with type 2 diabetes by the OGTT. The area under the curve receiver operating characteristic for A1C was 0.81 (95% CI 0.70-0.92). The threshold for identifying type 2 diabetes was 5.8%, with 78% specificity and 68% sensitivity. In the subgroup with repeated measures, a multivariate analysis showed that the strongest predictors of 2-h glucose at follow-up were baseline A1C and 2-h glucose, independently of age, ethnicity, sex, fasting glucose, and follow-up time.

CONCLUSIONS

The American Diabetes Association suggested that an A1C of 6.5% underestimates the prevalence of prediabetes and diabetes in obese children and adolescents. Given the low sensitivity and specificity, the use of A1C by itself represents a poor diagnostic tool for prediabetes and type 2 diabetes in obese children and adolescents.

Predisease: when does it make sense?

Screening often leads to finding conditions that are not at the stage or level that would classify them as disease but, at the same time, are not at a stage or level at which people can be declared entirely disease free. These "in-between" states have sometimes been designated as "predisease." Examples include precancerous lesions, increased intraocular pressure ("preglaucoma"), prediabetes, and prehypertension. When the goal of preventing adverse health outcomes is kept in mind, this review poses the idea that "predisease" as a category on which to act makes sense only if the following 3 conditions are met. First, the people designated as having predisease must be far more likely to develop disease than those not so designated. Second, there must be a feasible intervention that, when targeted to people with predisease, effectively reduces the likelihood of developing disease. Third, the benefits of intervening on predisease must outweigh the harms in the population. A systematic review of screening guidelines (published in 2003-2010) for 4 sample conditions (cervical cancer, glaucoma, diabetes, and hypertension) is included to assess whether they address these issues, followed by a discussion of the framework questions as they pertain to each condition.

Screening for type 2 diabetes and dysglycemia

Type 2 diabetes mellitus (T2DM) and dysglycemia (impaired glucose tolerance and/or impaired fasting glucose) are increasingly contributing to the global burden of diseases. The authors reviewed the published literature to critically evaluate the evidence on screening for both conditions and to identify the gaps in current understanding. Acceptable, relatively simple, and accurate tools can be used to screen for both T2DM and dysglycemia. Lifestyle modification and/or medication (e.g., metformin) are cost-effective in reducing the incidence of T2DM. However, their application is not yet routine practice. It is unclear whether diabetes-prevention strategies, which influence cardiovascular risk favorably, will also prevent diabetic vascular complications. Cardioprotective therapies, which are cost-effective in preventing complications in conventionally diagnosed T2DM, can be used in screen-detected diabetes, but the magnitude of their effects is unknown. Economic modeling suggests that screening for both T2DM and dysglycemia may be cost-effective, although empirical data on tangible benefits in preventing complications or death are lacking. Screening for T2DM is psychologically unharmful, but the specific impact of attributing the label of dysglycemia remains uncertain. Addressing these gaps will inform the development of a screening policy for T2DM and dysglycemia within a holistic diabetes prevention and control framework combining secondary and high-risk primary prevention strategies.

HbA1c may not be a sensitive determinant of diabetic status in the elderly

OBJECTIVE

American Diabetes Association (ADA) has recently recommended the use of glycated haemoglobin (HbA1c) to diagnose diabetes mellitus. We aim to determine if indeed this recommendation applies to the population in Singapore and whether it varies with age.

METHOD

This is a cross sectional study of 90 patients without previous history of diabetes who underwent screening and had both oral glucose tolerance test (OGTT) and HbA1c done at the same time. These patients were stratified into 4 age groups.

RESULT

We found that HbA1c of 6.2% is the best cut-off to diagnose diabetes using ROC curve analysis. At the specified HbA1c, the area under ROC curve (AUROC) reduces as age group increases suggesting that sensitivity and specificity of HbA1c as diagnostic marker reduces as age increases.

CONCLUSION

HbA1c has a low sensitivity to diagnose diabetes in older Asian subjects and caution is required when using HbA1c in isolation. This raises the possibility that a different cut-off value for different age groups may be more appropriate.

The prediabetic period: review of clinical aspects

Hyperglycemia that does not satisfy the diagnostic criteria for diabetes mellitus (DM) is generally called prediabetes (preDM). The global prevalence of preDM has been increasing progressively in the past few decades, and it has been established that preDM status is a strong risk factor for DM and cardiovascular disease. Currently, preDM status is classified into two subtypes: impaired fasting glucose and impaired glucose tolerance. Currently, preDM is not regarded as an independent clinical entity, but only as a risk factor for others. In this article, we review various clinical aspects of preDM in terms of the working definition, changes in criteria over the years, epidemiology, and pathophysiological characteristics, and its clinical significance in current medicine.

Hemoglobin A1c as a predictor of incident diabetes

OBJECTIVE

Several studies have suggested that HbA(1c) levels may predict incident diabetes. With new recommendations for use of HbA(1c) in diagnosing diabetes, many patients with HbA(1c) results below the diagnostic threshold will be identified. Clinicians will need to categorize risk for a subsequent diabetic diagnosis in such patients. The objective of this study was to determine the ability of HbA(1c) to predict the incidence of a diabetic diagnosis.

RESEARCH DESIGN AND METHODS

We performed a historical cohort study using electronic medical record data from two Department of Veterans Affairs Medical Centers. Patients (n = 12,589) were identified with a baseline HbA(1c) <6.5% between January 2000 and December 2001 and without a diagnosis of diabetes. Patients (12,375) had at least one subsequent follow-up visit. These patients were tracked for 8 years for a subsequent diagnosis of diabetes.

RESULTS

During an average follow-up of 4.4 years, 3,329 (26.9%) developed diabetes. HbA(1c) ≥ 5.0% carried a significant risk for developing diabetes during follow-up. When compared with the reference group (HbA(1c) <4.5%), HbA(1c) increments of 0.5% between 5.0 and 6.4% had adjusted odds ratios of 1.70 (5.0-5.4%), 4.87 (5.5-5.9%), and 16.06 (6.0-6.4%) (P < 0.0001). Estimates of hazard ratios similarly showed significant increases for HbA(1c) ≥ 5.0%. A risk model for incident diabetes within 5 years was developed and validated using HbA(1c), age, BMI, and systolic blood pressure.

CONCLUSIONS

The incidence of diabetes progressively and significantly increased among patients with an HbA(1c) ≥ 5.0%, with substantially expanded risk for those with HbA(1c) 6.0-6.4%.

Testosterone and modifiable risk factors associated with diabetes in men

OBJECTIVE

The role of endogenous testosterone in the pathogenesis of type 2 diabetes mellitus remains vague. We investigated whether associations between endogenous testosterone and diabetes prevalence in men could be partially explained by modifiable risk factors.

STUDY DESIGN

A random population-based cross-sectional study of 1195 men aged 35-80 years living in the north-west regions of Adelaide, Australia. Data collections occurred between 2002 and 2005, and response rate was 45.1%.

MATERIALS AND METHODS

Diabetes (non-specific) was classified by either: (1) self-report for doctor diagnosis of diabetes; (2) prescription medication for diabetes; (3) fasting plasma glucose ≥ 7 mmol/L; or (4) glycosylated haemoglobin ≥ 6.2%. Logistic regressions were used to estimate odds ratios (OR [with 95% confidence intervals]) for diabetes, with stepwise adjustments for demographic, lifestyle, and clinical factors.

RESULTS

Diabetes prevalence was positively associated with age groups 45-54 years (2.8 [1.4, 5.8]), 55-64 years (3.9 [1.9, 8.3]) and ≥ 65 years (4.0 [1.8, 8.9]), lowest income group (1.8 [1.0, 3.4]), ex-smoker (1.8 [1.2, 2.9]), lowest (3.2 [1.9, 5.5]) and middle (1.9 [1.1, 3.4]) alcohol tertiles, cardiovascular disease (1.9 [1.2, 2.8]), metabolic syndrome (4.0 [2.6, 6.1]), and lowest plasma total testosterone tertile (1.8 [1.1, 3.0]), but negatively associated with middle (0.5 [0.3, 0.8]) and highest (0.4 [0.3, 0.7]) sugar intake tertiles, arthritis (0.6 [0.3, 1.0]), and elevated LDL cholesterol (0.5 [0.3, 0.8]); ORs showed an inverted 'U' shape for middle and highest voiding lower urinary tract symptoms tertiles. Body composition, muscle strength, and cardio-metabolic factors partially explained the association between low plasma total testosterone and diabetes.

CONCLUSIONS

Plasma total testosterone was inversely and independently associated with diabetes prevalence, that might have been partially explained by several modifiable risk factors.

The performance of risk scores and hemoglobin A1c to find undiagnosed diabetes with isolated postload hyperglycemia

The aim of this study is to develop strategies to screen diabetic subjects with isolated postload hyperglycemia (IPH) in Chinese population. We included 1175 adult subjects who did not report diabetes were included. Diabetes was diagnosed by oral glucose tolerance tests. IPH was defined as fasting plasma glucose (FPG)<7 mmol/l and 2-hour post-load plasma glucose (2hPG) greater than 11.1 mmol/l. Using FPG criteria, only 59.8% of diabetic subjects were not identified, showing a poor agreement between FPG and 2hPG criteria (kappa 0.294). Age, FPG, total cholesterol, triglycerides, blood pressure, body mass index, HbA1c and medication for hypertension were associated factors for IPH. Four scores were constructed using all these factors, age and blood test results, age and HbA1c, and data from non-invasive examinations, respectively. The area under the ROC curve were 0.9296(95%CI 0.8948-0.9643), 0.9111(95%CI 0.8713-0.9508), 0.8902(95%CI 0.8341-0.9646), 0.8924(95%CI 0.7835-0.8753), and 0.8654(95%CI 0.7963-0.9345) for score 1, 2, 3, 4, and HbA1c, respectively. The sensitivity of all four risk scores to detect IPH was better than that of impaired fasting glucose (IFG). The sensitivity and specificity of HbA1c at cutoff 6.2% for detecting IPH was also better than that of IFG. In conclusion, the risk scores and HbA1c are useful to identify subjects with undiagnosed IPH, with better performance than IFG.

HbA(1c) measurement for the diagnosis of diabetes: is it enough?

AIM

To analyse the performance of HbA(1c) in diagnosing Type 2 diabetes based on fasting plasma glucose and/or 2-h plasma glucose measurements after a 75-g oral glucose tolerance test.

METHODS

This is a study of diagnostic test accuracy in individuals referred to the Clinical Pathology Department for oral glucose tolerance testing. After fasting overnight, HbA(1c), fasting plasma glucose and 2-h plasma glucose were measured. The receiver operating characteristic curve was used to evaluate the diagnostic performance of HbA(1c).

RESULTS

Four hundred and ninety-eight subjects (195 male, mean age 56 years) were enrolled and 115 (23.1%) were diagnosed with diabetes according to glucose-based methods and only 56 (11.2%) individuals were identified by HbA(1c) ≥ 6.5% (48 mmol/mol) (sensitivity 20.9%, specificity 95.3%). There is poor agreement between the newly recommended criterion and the current glucose-based diagnostic criteria (κ = 0.217; P < 0.001), probably because the diagnostic methods identify different populations of patients. Adding a glucose-based method into an algorithm, as proposed by the UK Department of Health, improved HbA(1c) performance.

CONCLUSIONS

HbA(1c) ≥ 6.5% (48 mmol/mol) showed limited sensitivity to diabetes diagnosis, although with high specificity. The results suggest that this cut-off point would not be enough to diagnose diabetes. Its use as the sole diabetes diagnostic test should be interpreted with caution to assure the correct classification of diabetic individuals.

Investigating concordance in diabetes diagnosis between primary care charts (electronic medical records) and health administrative data: a retrospective cohort study

BACKGROUND

Electronic medical records contain valuable clinical information not readily available elsewhere. Accordingly, they hold important potential for contributing to and enhancing chronic disease registries with the goal of improving chronic disease management; however a standard for diagnoses of conditions such as diabetes remains to be developed. The purpose of this study was to establish a validated electronic medical record definition for diabetes.

METHODS

We constructed a retrospective cohort using health administrative data from the Institute for Clinical Evaluative Sciences Ontario Diabetes Database linked with electronic medical records from the Deliver Primary Healthcare Information Project using data from 1 April 2006-31 March 2008 (N = 19,443). We systematically examined eight definitions for diabetes diagnosis, both established and proposed.

RESULTS

The definition that identified the highest number of patients with diabetes (N = 2,180) while limiting to those with the highest probability of having diabetes was: individuals with ≥2 abnormal plasma glucose tests, or diabetes on the problem list, or insulin prescription, or ≥2 oral anti-diabetic agents, or HbA1c ≥6.5%. Compared to the Ontario Diabetes Database, this definition identified 13% more patients while maintaining good sensitivity (75%) and specificity (98%).

CONCLUSIONS

This study establishes the feasibility of developing an electronic medical record standard definition of diabetes and validates an algorithm for use in this context. While the algorithm may need to be tailored to fit available data in different electronic medical records, it contributes to the establishment of validated disease registries with the goal of enhancing research, and enabling quality improvement in clinical care and patient self-management.

Global cardiovascular risk profiles of untreated hypertensives in an urban, developing community in Africa

Introduction

Blood pressure (BP) control in people of African descent is poor, largely because of a lack of treatment. Although the requirements for immediate initiation of antihypertensive drug therapy are defined by global cardiovascular risk, the global cardiovascular risk profiles of untreated hypertensives at a community level are uncertain.

Aim

To identify the distribution of global cardiovascular risk profiles of untreated hypertensives in an urban, developing community of African descent in South Africa.

Methods

As part of the African Programme on Genes in Hypertension, we assessed nurse-derived clinic BP (the mean of five standardised BP values obtained according to guidelines), current antihypertensive therapy, and total cardiovascular risk in 1 029 participants older than 16 years of age from randomly selected nuclear families from the South West Township of Gauteng (SOWETO).

Results

Approximately 46% of participants had systolic/diastolic BP values ≥ 140/90 mmHg and ~23% of participants were hypertensives not receiving antihypertensive medication. Approximately 12% of untreated hypertensives had a high added risk and ~18% a very high added risk (6.7% of the total sample). In untreated hypertensives, in contrast to the absence of severe hypertension and diabetes mellitus in those with lower risk profiles, a high cardiovascular risk profile in this group was characterised by severe hypertension in ~52% and diabetes mellitus in ~33%. Based on a high added risk carrying at least a 20% chance and a very high added risk at least a 30% chance of a cardiovascular event in 10 years, this translates into 1 740 events per 100 000 of the population within 10 years, events that could be prevented through antihypertensive drug therapy.

Conclusions

In an urban, developing community of African ancestry, a significant proportion (6.7%) of people may have untreated hypertension and a global cardiovascular risk profile that suggests a need for antihypertensive drug therapy. Cardiovascular risk in this group is driven largely by the presence of severe hypertension or diabetes mellitus.

Association between the 1291-C/G polymorphism in the adrenergic α-2a receptor and the metabolic syndrome

The prevalence of the metabolic syndrome is increased in patients with schizophrenia compared with the general population. The strong interindividual differences in susceptibility to developing the metabolic syndrome suggests that the genetic makeup is a modulating factor. Part of the genetic puzzle can possibly be explained by variations in the gene coding for the adrenergic α-2a receptor (ADRA2A) because this receptor plays an important role in lipolysis. Three studies have found an association between the α-2a 1291-C/G polymorphism and antipsychotic induced weight gain, with conflicting results between whites and Asians. No studies have been published investigating the association between the 1291-C/G polymorphism and the metabolic syndrome. The primary objective of this cross-sectional study was to investigate the association between the ADRA2A 1291-C/G polymorphism and the metabolic syndrome in 470 patients using antipsychotic drugs. There was no significant association between carriership of the variant 1291-G allele and prevalence of the metabolic syndrome (odds ratio, 0.73; 95% confidence interval, 0.49-1.15). Exploratory analysis showed an association between carriership of the variant 1291-G allele and a reduced prevalence of the metabolic syndrome in patients not currently using antipsychotics (odds ratio, 0.05; 95% confidence interval, 0.003-0.97; P = 0.048). In conclusion, this study shows that the ADRA2A 1291-C/G polymorphism does not seem to be a strong predictor for long-term occurrence of the metabolic syndrome in antipsychotic using patients. Studies investigating this association using a prospective, or retrospective, design, as well as studies investigating this association in a nonpsychiatric population, are warranted.

Glycated haemoglobin and blood pressure-lowering effect of cinnamon in multi-ethnic Type 2 diabetic patients in the UK: a randomized, placebo-controlled, double-blind clinical trial

AIMS

To determine the blood glucose lowering effect of cinnamon on HbA1c, blood pressure and lipid profiles in people with type 2 diabetes.

METHODS

58 type 2 diabetic patients (25 males and 33 females), aged 54.9 ± 9.8, treated only with hypoglycemic agents and with an HbA1c more than 7% were randomly assigned to receive either 2g of cinnamon or placebo daily for 12 weeks.

RESULTS

After intervention, the mean HbA1c was significantly decreased (P<0.005) in the cinnamon group (8.22% to 7.86%) compared with placebo group (8.55% to 8.68%). Mean systolic and diastolic blood pressures (SBP and DBP) were also significantly reduced (P<0.001) after 12 weeks in the cinnamon group (SBP: 132.6 to 129.2 mmHg and DBP: 85.2 to 80.2 mmHg) compared with the placebo group (SBP: 134.5 to 134.9 mmHg and DBP: 86.8 to 86.1 mmHg). A significant reduction in fasting plasma glucose (FPG), waist circumference and body mass index (BMI) was observed at week 12 compared to baseline in the cinnamon group, however, the changes were not significant when compared to placebo group. There were no significant differences in serum lipid profiles of total cholesterol, triglycerides, HDL and LDL cholesterols neither between nor within the groups.

CONCLUSIONS

Intake of 2g of cinnamon for 12 weeks significantly reduces the HbA1c, SBP and DBP among poorly controlled type 2 diabetes patients. Cinnamon supplementation could be considered as an additional dietary supplement option to regulate blood glucose and blood pressure levels along with conventional medications to treat type 2 diabetes mellitus.

Relationship Between Urinary Salt Excretion and Pulse Pressure and Central Aortic Hemodynamics Independent of Steady State Pressure in the General Population

Although central pulse pressure (PPc) is strongly related to central mean arterial pressure (MAPc), PPc predicts cardiovascular outcomes beyond MAPc. Whether modifiable risk factors for hypertension contribute to PPc and its determinants, independent of MAPc, is uncertain. In 635 randomly recruited participants, we assessed the independent relationship between 24-hour urinary sodium (Na + ) or potassium (K + ) excretion and brachial artery PP (in office or 24-hour; n=487), PPc, the forward (P1) and augmented (Paug) pressure wave components of PPc, central augmentation index, and determinants of central pressure waves, including aortic pulse wave velocity, effective reflecting distance, and reflective wave transit time. Central dynamics were determined using applanation tonometry of the carotid, femoral, and radial arteries. With adjustments for potential confounders, urinary Na + /K + was independently associated with in-office, central, and 24-hour PP, as well as Paug, P1, and central augmentation index ( P <0.05 to P <0.005). With further adjustments for MAPc (or diastolic BP), urinary Na + /K + was independently associated with PPc, 24-hour PP, Paug, P1, and central augmentation index ( P <0.05 to P =0.005) but not with in-office PP, pulse wave velocity, effective reflecting distance, or reflective wave transit time. In conclusion, in a population of African ancestry, urinary salt excretion is independently related to central and 24-hour PP independent of MAPc or diastolic BP, effects that are attributed to increases in both P1 and Paug but not to pulse wave velocity. Hence, modifying salt intake could influence cardiovascular risk through effects on 24-hour and central PPs, as well as P1 and Paug, independent of steady-state pressure (MAP or diastolic BP) or pulse wave velocity.

Screening strategy for type 2 diabetes in the United Arab Emirates

The prevalence of type 2 diabetes mellitus (DM) among Emirati nationals is one of the highest in the world. The recently released United Arab Emirates National DM guidelines call for screening all adults aged 30 years and more. The authors explored the need for such a modification of current American Diabetes Association (ADA) guidelines. They also considered the prevalence rates for undiagnosed DM based on oral glucose tolerance test (OGTT) versus glycohemoglobin (HbA( 1c)) >or= 6.5% in a population-based sample of 296 adult Emirati participants. In the low-risk ADA category, defined by age <45 years and BMI <25, only 1 of 68 (1.5%) participants was diagnosed with DM. The overall rate of DM based on HbA(1c) was lower than that based on OGTT (10.1% versus 14.2%; P < .05). The authors conclude that the ADA guidelines are adequate for screening in this high-risk population. They also find high discordance between HbA(1c) and OGTT.

Combined use of fasting plasma glucose and glycated hemoglobin A1c in the screening of diabetes and impaired glucose tolerance

The aim of this study is to assess the validity of combined use of fasting plasma glucose (FPG) and glycated hemoglobin A1c (HbA1c) as screening tests for diabetes and impaired glucose tolerance (IGT) in high-risk subjects. A total of 2,298 subjects were included. All subjects underwent a 75-g oral glucose tolerance test (OGTT) and HbA1c measurement. Receiver operating characteristic curve (ROC curve) analysis was used to examine the sensitivity and specificity of FPG and HbA1c for detecting diabetes and IGT, which was defined according to the 1999 World Health Organization (WHO) criteria. (1) Based on the ROC curve, the optimal cut point of FPG related to diabetes diagnosed by OGTT was 6.1 mmol/l that was associated with a sensitivity and specificity of 81.5 and 81.0%, respectively; The optimal cut point of HbA1c related to diabetes diagnosed by OGTT was 6.1%, which was associated with a sensitivity and specificity of 81.0 and 81.0%, respectively; The screening model using FPG > or = 6.1 mmol/l or HbA1c > or = 6.1% had sensitivity of 96.5% for detecting undiagnosed diabetes; the screening model using FPG > or = 6.1 mmol/l and HbA1c > or = 6.1% had specificity of 96.3% for detecting undiagnosed diabetes. (2) Based on the ROC curve, the optimal cut point of FPG related to IGT diagnosed by OGTT was 5.6 mmol/l that was associated with a sensitivity and specificity of 64.1 and 65.4%, respectively; The optimal cut point of HbA1c related to IGT diagnosed by OGTT was 5.6%, which was associated with a sensitivity and specificity of 66.2 and 51.0%, respectively; The screening model using FPG > or = 5.6 mmol/l or HbA1c > or = 5.6% had sensitivity of 87.9% for detecting undiagnosed IGT; The screening model using FPG > or = 5.6 mmol/l and HbA1c > or = 5.6% had specificity of 82.4% for detecting undiagnosed IGT. Compared with FPG or HbA1c alone, the simultaneous measurement of FPG and HbA1c (FPG and/or HbA1C) might be a more sensitive and specific screening tool for identifying high-risk individuals with diabetes and IGT at an early stage.