Comparison of hemoglobin A1c and hemoglobin A1 in diabetic patients

Impact of chronic emotions and psychosocial stress on glycemic control in patients with type 1 diabetes. Heterogeneity of glycemic responses, biological mechanisms, and personalized medical treatment

Many studies have clearly established that chronic psychosocial stress may sustainably worsen glycemic control in patients with type 1 diabetes mellitus (T1DMM), thus promoting diabetes complications. Chronic psychosocial stress may be due to: i) the long-term accumulation of stressful life events that require readjustment on the part of the individual (loosing friends, changing schools), and/or ii) exposure to severe chronic stressors (persistent difficulties and adversities of life). Whatever the reason, many studies have clearly established a positive correlation between chronic psychosocial stress and HbA1c levels. However, a small fraction of patients is minimally affected or not affected at all by chronic psychosocial stress. Conversely, positive life events can substantially improve glycemic control. Recent evidence suggests the existence of subpopulations that differ in personality traits, neurohormonal regulatory responses, and food intake behavior (increased or decreased). Better characterization of the clinical and neurohormonal differences between these subpopulations may help develop personalized treatment strategies in the future. In the near future, psychotherapeutic support and automated insulin delivery (AID) could alleviate chronic stress, prevent worsening glycemic control, and ease the burden of diabetes.

A Novel Approach for Glycosylated Hemoglobin Testing Using Microchip Affinity Electrophoresis

OBJECTIVE

Effective management of diabetes largely benefits from early diagnosis followed by intensive long-term regulation of blood glucose. The levels of glycohemoglobin (HbA1 and HbA1c) have been used as standard biomarkers to assess long-term blood glucose concentrations for diabetes diagnosis and management. Gold standard laboratory methods for HbA1 and HbA1c testing are often costly and not widely available. Moreover, currently available point-of-care (POC) immunoassay-based glycohemoglobin tests may produce inaccurate test results for patients with co-existing diseases such as hemoglobin disorders and anemia. Here, we report a POC platform, HemeChip-GHb, for quantitative HbA1 detection leveraging paper-based affinity electrophoresis.

METHODS

We describe the design and development of the HemeChip-GHb test. Feasibility and accuracy of the HemeChip-GHb system were demonstrated by testing blood samples collected from healthy donors, patients with prediabetes, and patients with diabetes.

RESULTS

HbA1 levels measured with HemeChip-GHb show 0.96 correlation to the levels reported from the clinical standard HPLC tests, and with a bias of -0.72% based on Bland-Altman analysis. 99.6% of the HbA1 levels for paired HemeChip-GHb and HPLC fell within A and B zones of no difference in clinical outcome based on error grid analysis.

CONCLUSION

Using HemeChip-GHb we achieved accurate diabetes status detection with sensitivity and specificity of 100%.

SIGNIFICANCE

We presented a novel POC paper-based affinity electrophoresis platform that has the potential for accurately diagnosing diabetes, and addressing an unmet need for accurate and affordable diagnostics in resource-challenged environments.

Long term type 1 diabetes is associated with hand pain, disability and stiffness but not with structural hand osteoarthritis features - The Dialong hand study

OBJECTIVE

To explore whether having long-term type 1 diabetes (>45 years) is associated with a higher prevalence of radiographic hand OA, erosive hand OA and increased hand pain, disability and stiffness.

METHODS

In total N = 96 persons with type 1 diabetes diagnosed before 1970 were included (mean [SD] age: 62.2 [7.4], mean [SD] HbA1c: 7.43 [0.80] and N = 49 [51%] men). Regular measurements of their HbA1c were obtained till 2015. We included N = 69 healthy controls without any diabetes (mean [SD] age: 63.0 [7.0], mean [SD] HbA1c: 5.41 [0.32], N = 29 [42%] men). The groups were compared for radiographic hand OA (Kellgren-Lawrence grade ≥2 in ≥1 joint) and erosive hand OA (central erosions in ≥1 joint), Australian/Canadian index (AUSCAN) for hand pain, disability and stiffness using regression analyses adjusted for age, sex, educational level and waist circumference.

RESULTS

We found no associations between having long term type 1 diabetes and more prevalent radiographic hand OA (OR = 0.83, 95% CI = 0.38-1.81). We found a trend towards higher prevalence of erosive hand OA in diabetes patients (OR = 2.96, 95% CI = 0.82-10.64). Strong and consistent associations were observed between long term type 1 diabetes and increased hand pain (B = 2.78, 95% CI = 1.65-3.91), disability (B = 5.30, 95% CI = 3.48-7.12) and stiffness (B = 2.00, 95% CI = 1.33-2.67). These associations were particularly strong for women and participants below the median age of 61 years.

CONCLUSION

Long-term type 1 diabetes was not associated with radiographic hand OA, but was strongly associated with hand pain, disability and stiffness. The association between diabetes and erosive hand OA warrants further investigation.

Lipoprotein metabolism in patients with type 1 diabetes under intensive insulin treatment

Background

Type 1 diabetes (T1DM) is frequently accompanied by dyslipidemia related with insulin-dependent steps of the intravascular lipoprotein metabolism. T1DM dyslipidemia may predispose to precocious cardiovascular disease and the lipid status in T1DM under intensive insulin treatment has not been sufficiently explored. The aim was to investigate the plasma lipids and the metabolism of LDL and HDL in insulin-treated T1DM patients with high glycemic levels.

Methods

Sixteen male patients with T1DM (26 ± 7 yrs) with glycated hemoglobin >7%, and 15 control subjects (28 ± 6 yrs) were injected with a lipid nanoemulsion (LDE) resembling LDL and labeled with ¹⁴C-cholesteryl ester and ³H-free-cholesterol for determination of fractional clearance rates (FCR, in h^-1) and cholesterol esterification kinetics. Transfer of labeled lipids from LDE to HDL was assayed in vitro.

Results

LDL-cholesterol (83 ± 15 vs 100 ± 29 mg/dl, p=0.08) tended to be lower in T1DM than in controls; HDL-cholesterol and triglycerides were equal. LDE marker ¹⁴C-cholesteryl ester was removed faster from plasma in T1DM patients than in controls (FCR=0.059 ± 0.022 vs 0.039 ± 0.022h-1, p=0.019), which may account for their lower LDL-cholesterol levels. Cholesterol esterification kinetics and transfer of non-esterified and esterified cholesterol, phospholipids and triglycerides from LDE to HDL were also equal.

Conclusion

T1DM patients under intensive insulin treatment but with poor glycemic control had lower LDL-cholesterol with higher LDE plasma clearance, indicating that LDL plasma removal was even more efficient than in controls. Furthermore, HDL-cholesterol and triglycerides, cholesterol esterification and transfer of lipids to HDL, an important step in reverse cholesterol transport, were all normal. Coexistence of high glycemia levels with normal intravascular lipid metabolism may be related to differences in exogenous insulin bioavailabity and different insulin mechanisms of action on glucose and lipids. Those findings may have important implications for prevention of macrovascular disease by intensive insulin treatment.

Glycemia and cardiovascular disease in type 1 diabetes mellitus

OBJECTIVE

To evaluate the role of glycemic control in the development of cardiovascular disease (CVD) in type 1 diabetes mellitus (DM).

METHODS

We review the literature regarding coronary atherosclerosis, coronary artery calcification, and the epidemiologic studies related to the role of glycemia and the classic risk factors for coronary artery disease (CAD) in type 1 DM.

RESULTS

Four prospective studies (Wisconsin Epidemiologic Study of Diabetic Retinopathy, EURODIAB, Steno Diabetes Center Study of Adults With Type 1 DM, and Pittsburgh Epidemiology of Diabetes Complications study) do not show that glycemic control predicts CAD occurrence. Findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study show that compared with conventional insulin therapy, intensive insulin therapy reduces CVD among patients with type 1 DM and is associated with lower prevalence of coronary artery calcification. The discrepancies between the findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study and the Pittsburgh Epidemiology of Diabetes Complication study are likely due to differences between the study populations and the lower prevalence of renal disease in the former study. Besides duration of DM and albuminuria/overt nephropathy, insulin resistance is a major determinant of CAD associated with type 1 DM.

CONCLUSIONS

Discrepant study results regarding the relationship between glycemia and CAD/coronary artery calcification may be related to the prevalence of renal disease and the presence of the metabolic syndrome. Published data suggest that addressing traditional risk factors including albuminuria, the metabolic syndrome, and inflammatory markers is better for preventing and treating CAD than focusing exclusively on glycemic control, which is still necessary for preventing microvascular complications. Furthermore, there is a synergistic effect of glycemic control and albuminuria on the development of CVD.

[Cardiovascular disease in type 1 diabetes mellitus]

The association between type 1 diabetes and coronary heart disease has become very clear since the late 1970. It has been demonstrated that there is an important increased risk in morbidity and mortality caused by coronary artery disease in young adults with type 1 diabetes compared with the non diabetic population. The underlying pathogeneses is still poorly understood. While the role of glycemic control in the development of microvascular disease complication is well established its role in CVD in patients with DM1 remains unclear with epidemiologic studies reporting conflicting data. Recent findings from the DCCT/EDIC showed that prior intensive diabetes treatment during the DCCT was associated with less atherosclerosis, largely because of reduced level of HbA1c during the DCCT. The improvement of glycemic control itself appeared to be particularly effective in younger patients with shorter duration of the disease. Other analyses suggested the glycemia may have a stronger effect on CAD in patients without than in those with albuminúria. Other major determinants of coronary artery disease are the components of metabolic syndrome and the surrogate measure of insulin resistence: eGDR. It is proposed that patients with DM1 should have aggressive medical therapy, risk factor modification and careful monitoring not only of his blood sugar but also of the other processes involved in the atherosclerotic process, mostly the ones with family history of type 2 diabetes.

Long-Term Efficacy and Tolerability of Acarbose Treatment in Patients with Type 2 Diabetes Mellitus

OBJECTIVE

The aim of the study was to investigate the efficacy and tolerability of long-term acarbose therapy in type 2 diabetic patients.

STUDY DESIGN

In this double-blind, single-centre group comparison, patients were randomised to receive either acarbose or matching placebo, in addition to their regular antidiabetic therapy, over a period of 78 weeks. Eligibility for inclusion in the efficacy evaluation included a study duration of >/=510 days.

METHODS

The primary efficacy parameter was the change in glycosylated haemoglobin (HbA(1)) from baseline to end of study. Secondary variables included changes in blood glucose and lipid parameters, as well as signs of retinopathy and nephropathy.

PATIENTS

A total of 139 patients were assessed for safety and 88 patients (44 in each treatment group) were included in the efficacy analysis. Patients were generally overweight and the majority had previously been treated with sulphonylureas.

RESULTS

Acarbose significantly improved fasting and 1-hour postprandial blood glucose levels compared with placebo (p = 0.039 and 0.009), and improvements in HbA(1) with acarbose versus placebo fell just short of significance (p = 0.057). There were no differences between treatments in changes in microvascular complications, but blood pressure improved with acarbose treatment. Two patients in the acarbose group experienced elevated liver enzyme levels. Generally, acarbose had a good safety profile and was well tolerated.

CONCLUSION

Long-term treatment with acarbose was safe and efficacious in patients with type 2 diabetes mellitus that was insufficiently controlled by other oral antidiabetics.

Monitoring diabetic control in developing countries: a review of glycated haemoglobin and fructosamine assays

Measurement of glycated proteins, especially haemoglobins, is now a routine procedure for monitoring previous glycaemic control in diabetic patients in the developed world. Until recently, however, the assays were sophisticated and costly and, therefore, were only rarely used in developing countries. With easier and cheaper tests now available, the measurement of glycaemic control could be also introduced into regional hospitals in developing countries. This paper reviews feasible methods for clinical laboratories with limited resources. Recent experiences from African countries are included.

Glycated haemoglobins

The association between elevated levels of glycated haemoglobins and diabetes mellitus has been known for twenty years [92]. Since then the determination of glycated haemoglobins has become a valuable tool for the objective assessment of long-term glycaemia in diabetic patients. The marked clinical interest in reliable measurements of glycated haemoglobins has stimulated the development and perfection of the necessary methodology. Limitations of the techniques have led to investigation of the underlying causes. Some of them led to the recognition of processes that were not known to occur in vivo before, such as glycation at sites other than the amino terminus of the beta-chains, modification of haemoglobin by reactants other than glucose or the existence of labile haemoglobin adducts. With ideal methodology these features would have gone unnoticed. Furthermore, the determination of glycated haemoglobin in large populations of diabetic patients has lead to the discovery of new, clinically silent mutant haemoglobins. Today, the routine determination of glycated haemoglobins in diabetic patients probably represents the broadest screening for mutant haemoglobins. The experience with glycated haemoglobins shows that overcoming difficulties in their determination, and progress in biomedical research, are closely intertwined.

Comparison of three methods for the elimination of the labile fraction of HbA1

Three different procedures were used to remove the "labile" fraction in the chromatographic quantitation of hemoglobin A1 (HbA1) by a minicolumn assay: (a) preincubation of the erythrocytes at 37 degrees C in isotonic saline for 4 h, (b) preincubation in the presence of semicarbazide-aniline at pH 5.0 for 30 min, and (c) preincubation in acetate buffer at pH 5.5 for 30 min. The results show that the two latter methods are not only more rapid but are also slightly more effective. The use of the acetate buffer is preferred because this reagent is more easily prepared and also because the presence of semicarbazide and aniline did not markedly accelerate the dissociation of Hb pre-A1c at pH 5.5. The procedure relies simply on the greater instability of Schiff base in acidic solution. There is a significant correlation between the "labile" fraction and the plasma glucose concentration at sampling time. The results support the view that the elimination of the "labile" precursor is essential to preserve the utility of the assay.

Glycosylated haemoglobins: biochemical evaluation and clinical utility

A review is given of the biochemical background of the glycosylated haemoglobins, their methods of determination, and their clinical significance. Special attention is paid to the sample preparation. For all methods except the colorimetric TBA-method, the removal of the labile pre-HbA1c fraction is essential. Under proper conditions, high-performance liquid chromatography, agar-gel electrophoresis and affinity chromatography are suitable methods for use in the clinical laboratory for the estimation of HbA1c and HbA1. However, the colorimetric TBA-method must be considered to be the method of choice. The clinical utility of the test is stressed with special respect to the management of diabetic pregnancies, the control of home-monitoring of blood glucose, and the objective measurement of the effect of changing diabetic therapy.

Increase in stable glycosylated haemoglobin after induction of poor glycaemic control

Eight insulin-treated diabetic patients in good glycaemic control were studied as out-patients with frequent determinations of stable glycosylated haemoglobin (HbA1c) before, during and after 1 week of induced poor glycaemic control. Stable HbA1c was determined by cation exchange chromatography after elimination of the labile fraction by incubation in saline (0.15 mol/l). The increase in mean blood glucose was significant on the first day of reduced insulin therapy and greatest after 1 week (6.9 +/- 3.9 mmol/l above basal values). Stable HbA1c increased significantly on day 7 of the reduced insulin treatment. The increase represented, on average, 0.009% of total haemoglobin per mmol/l increase in mean blood glucose per 24 h during the period of induced hyperglycaemia. After restoring insulin therapy, a significant decrease in blood glucose was achieved on day 1 and after 2 days, the blood glucose level was similar to before the study. There was no significant decrease in stable HbA1c within the first 2 weeks of improved glycaemia.

Comparison of column chromatographic, colorimetric and electrophoretic methods for determination of glycosylated hemoglobin (HbA1)

A comparison of two column chromatographic (BioRad & Helena), an electrophoretic (Corning) and a colorimetric method for the determination of glycosylated hemoglobin (HbA1) was performed. Blood samples were obtained from a diverse diabetic population and normal persons. Inter-and intra-run precision studies with normal and above normal HbA1 samples indicated that there was no statistically significant difference (p greater than 0.05) in precision among the methods. The electrophoretic and BioRad column chromatographic methods showed best correlation (r = 0.96 p less than 0.001 y = 0.465 + 1.036 x), while the colorimetric method gave HbA1 levels consistently higher than those obtained by electrophoresis (r = 0.852 p less than 0.001 y = 4.99 + 0.867 x). The effects of preincubation to remove labile glycosylated hemoglobin with saline or semicarbazide - aniline preincubation were also studied. There was no statistically significant difference (p greater than 0.05) in the HbA1 levels from erythrocytes after saline preincubation as compared to nontreated samples. Further investigation concerning the value of preincubation to remove the labile HbA1 fraction is warranted.