Standardization of HbA1c measurements: a consensus statement

External validation of the UK prospective diabetes study (UKPDS) risk engine in patients with type 2 diabetes identified in the national diabetes program in Iran

Background

Cardiovascular diseases are the first leading cause of mortality in the world. Practical guidelines recommend an accurate estimation of the risk of these events for effective treatment and care. The UK Prospective Diabetes Study (UKPDS) has a risk engine for predicting CHD risk in patients with type 2 diabetes, but in some countries, it has been shown that the risk of CHD is poorly estimated. Hence, we assessed the external validity of the UKPDS risk engine in patients with type 2 diabetes identified in the national diabetes program in Iran.

Methods

The cohort included 853 patients with type 2diabetes identified between March 21, 2007, and March 20, 2018 in Lorestan province of Iran. Patients were followed for the incidence of CHD. The performance of the models was assessed in terms of discrimination and calibration. Discrimination was examined using the c-statistic and calibration was assessed with the Hosmer-Lemeshow χ2 statistic (HLχ2) test and a calibration plot was depicted to show the predicted risks versus observed ones.

Results

During 7464.5 person-years of follow-up 170 first Coronary heart disease occurred. The median follow-up was 8.6 years. The UKPDS risk engine showed moderate discrimination for CHD (c-statistic was 0.72 for 10-year risk) and the calibration of the UKPDS risk engine was poor (HLχ2 = 69.9, p < 0.001) and the UKPDS risk engine78% overestimated the risk of heart disease in patients with type 2 diabetes identified in the national diabetes program in Iran.

Conclusion

This study shows that the ability of the UKPDS Risk Engine to discriminate patients who developed CHD events from those who did not; was moderate and the ability of the risk prediction model to accurately predict the absolute risk of CHD (calibration) was poor and it overestimated the CHD risk. To improve the prediction of CHD in patients with type 2 diabetes, this model should be updated in the Iranian diabetic population.

Okra [Abelmoschus esculentus (L.) Moench] improved blood glucose and restored histopathological alterations in splenic tissues in a rat model with streptozotocin-induced type 1 diabetes through CD8+ T cells and NF-kβ expression

Diabetes mellitus is a complex metabolic syndrome that involves dysfunction of spleen and other lymphoid organs. Medicinal plants, including okra (Abelmoschus esculentus (L.) Moench), were used widely for diabetes treatment. Scarce data are available about the potential anti-diabetic effects of okra, the histopathological alterations in splenic tissues and the mechanistic pathways underlying this association. The current research investigated the effects of okra pod extract on the biochemical parameters and expression of CD8+ T cells and nuclear factor kappa (NF-k) B and releasing proinflammatory cytokines in spleen in streptozotocin (STZ)-induced diabetic rat models. A total of 50 mature male Wister albino rats were divided into five isolated groups; the first served as control (untreated) animals, the second (DM group) diabetes induced by STZ (at a dose of 45 mg/kg body weight, administered intraperitoneally), the third group (DM + Insulin): diabetic rats administered insulin subcutaneously (10 units/kg bw/day) daily for 4 weeks, the fourth group was administrated 400 mg/kg okra extract daily for 4 weeks, and diabetic induced rats in the fifth group were administrated 400 mg/kg okra extract daily for 4 weeks. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity in Abelmoschus esculentus (L.) Moench was studied, and the content of phenolic compounds in okra pods was estimated using high-performance liquid chromatography. Diabetes induction led to decreased body weight, increased blood glucose levels. Capsular thickness was significantly increased, white pulp was widely dispersed, and mature lymphocytes in the periphery were also drastically decreased, with thick follicular arteries, necrosis, and depletion of lymphocytes in the germinal center. Red pulp revealed severe congestion and degenerative changes, deposition of hemosiderin granules and lymphocytic depletion. In addition, collagen fiber deposition was increased also in this group. The induction of diabetes exaggerated NF-kβ expression and mediated downregulation of the expression of CD8+ T cells in spleen tissue. Interestingly, oral administration of okra extracts post diabetes induction could mitigate and reverse such adverse effects. Altogether, our study points out the potential benefits of okra in improving blood glucose levels and restoring histopathological alterations in splenic tissues through CD8+ T cells and NF-kβ expression in a diabetic rat model.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association for Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (HbA1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of HbA1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Analysis of the Influence of Diabetic Nephropathy in Patients with Diabetic Foot Osteomyelitis

This study analyzed the influence of diabetic nephropathy on the healing prognosis after conservative surgery in diabetic foot osteomyelitis (DFO). A retrospective observational study was carried out between January 2021 and December 2022 and involved 278 outpatients with a diagnosis of DFO at a specialized diabetic foot unit, including 74 (26.62%) patients with DN (group 2) and 204 (73.38%) patients without DN (group 1). There were 266 (95.70%) ulcers on the forefoot, 8 (2.90%) on the midfoot, and 4 (1.45%) on the hindfoot (p = 0.992). The healing rates were 85.1% (n = 63) for group 2 and 81.3% (n = 165) for group 1 (p = 0.457). When exploring the influence of DN on the risk of delayed ulcer healing, the results did not show a significant effect [12 (6; 28) weeks among patients with DN vs. 12 (6; 21) weeks among patients without DN; p = 0.576]. No significant differences were observed in complications, with one (2.59%) death occurring in group 1 (p = 0.296) and three minor amputations being performed in both groups [two (5.13%) amputations in group 1 vs. one amputation (9.09%) in group 2; p = 0.217]. Bone cultures were performed for a total of 190 patients (133 in group 1 and 57 in group 2). Of these, 176 positive bone cultures were isolated: 71 positive bone cultures (57.7%) were monomicrobial cultures in group 1, with 30 (56.6%) in group 2. There were 52 (42.3%) that had at least two microorganisms in group 1, and 23 (43.4%) in group 2 (p = 0.890). The most frequently prescribed oral antibiotic was amoxicillin/clavulanate (43.89%), followed by levofloxacin (28.4%), and trimethoprim/sulfamethoxazole (14.7%). This study shows that DN does not have a significant influence on the healing prognosis of patients with DFO after conservative surgery.

Melatonin downregulates the increased hepatic alpha-fetoprotein expression and restores pancreatic beta cells in a streptozotocin-induced diabetic rat model: a clinical, biochemical, immunohistochemical, and descriptive histopathological study

Background

Diabetes mellitus (DM) is a chronic metabolic disorder. Hepatopathy is one of the serious effects of DM Melatonin (MT) is a potent endogenous antioxidant that can control insulin output. However, little information is available about the potential association between melatonin and hepatic alpha-fetoprotein expression in diabetes.

Objective

This study was conducted to assess the influence of MT on diabetes-related hepatic injuries and to determine how β-cells of the pancreas in diabetic rats respond to MT administration.

Materials and methods

Forty rats were assigned to four groups at random (ten animals per group). Group I served as a normal control group. Group II was induced with DM, and a single dose of freshly prepared streptozotocin (45 mg/kg body weight) was intraperitoneally injected. In Group III, rats received 10 mg/kg/day of intraperitoneal melatonin (IP MT) intraperitoneally over a period of 4 weeks. In Group IV (DM + MT), following the induction of diabetes, rats received MT (the same as in Group III). Fasting blood sugar, glycosylated hemoglobin (HbA1c), and serum insulin levels were assessed at the end of the experimental period. Serum liver function tests were performed. The pancreas and liver were examined histopathologically and immunohistochemically for insulin and alpha-fetoprotein (AFP) antibodies, respectively.

Results

MT was found to significantly modulate the raised blood glucose, HbA1c, and insulin levels induced by diabetes, as well as the decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Furthermore, MT attenuated diabetic degenerative changes in the pancreas and the hepatic histological structure, increased the β-cell percentage area, and decreased AFP expression in the liver tissue. It attenuated diabetes-induced hepatic injury by restoring pancreatic β-cells; its antioxidant effect also reduced hepatocyte injury.

Conclusion

Collectively, the present study confirmed the potential benefits of MT in downregulating the increased hepatic alpha-fetoprotein expression and in restoring pancreatic β-cells in a streptozotocin-induced diabetic rat model, suggesting its promising role in the treatment of diabetes.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association of Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (Hb A1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of Hb A1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Bacterial Diversity and Antibiotic Resistance in Patients with Diabetic Foot Osteomyelitis

This study analysed the bacterial diversity, antibiotic susceptibility, and resistance in patients with complications of diabetic foot osteomyelitis (DFO). A retrospective observational study was carried out between September 2019 and September 2022 and involved 215 outpatients with a diagnosis of DFO at a specialized diabetic foot unit. A total of 204 positive bone cultures were isolated, including 62.7% monomicrobial cultures, and 37.3% were formed with at least two microorganisms. We observed that Proteus spp., Coagulase-negative staphylococci (CoNS), Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Corynebacterium were the most frequently isolated microorganisms and accounted for more than 10% of the DFO cases. With stratification by Gram-positive (GP) and Gram-negative (GN) bacteria, we observed that 91.6% of cultures presented at least one GP bacteria species, and 50.4% presented at least one GN bacteria species. The most common GP species were CoNS (29%), S. aureus (25.8%), and Corynebacterium spp. (14%). The most frequent GN species consisted of Proteus spp. (32%), P. aeruginosa (23.3%), and E. coli (17.5%). The main antibiotics with resistance to GP-dominated infections were penicillins without β-lactamase inhibitor, and those in GN-dominated infections were sulfonamides and penicillins without β-lactamase. Significant differences were not observed in mean healing time in DFU with acute osteomyelitis (12.76 weeks (4.50;18)) compared to chronic osteomyelitis (15.31 weeks (7;18.25); p = 0.101) and when comparing cases with soft tissue infection (15.95 (6;20)) and those without such an infection (16.59 (7.25;19.75), p = 0.618). This study shows that when treatment of DFO is based on early surgical treatment, the type of DFO and the presence of soft infection are not associated with different or worse prognoses.

Melatonin ameliorates the adrenal and pancreatic alterations in streptozotocin-induced diabetic rats: Clinical, biochemical, and descriptive histopathological studies

Previous studies have demonstrated the beneficial effects of melatonin in diabetic rats. However, limited studies have been conducted on the potential effects of melatonin on the descriptive histopathological and morphometric findings in different compartments of the adrenal glands in diabetic animal models. In this study, using a streptozotocin (STZ)-induced diabetic rat model, we sought to examine histological alterations in the pancreas and adrenal glands and observe the effect of the administration of melatonin on the histopathology and morphology of the pancreas and the adrenal gland cortex and medulla that are altered by STZ-induced hyperglycemia. Rats were randomly assigned to four different groups: Group I, normal control; Group II, melatonin group (MT) (10 mg/kg/day); Group III, (diabetic STZ group), and Group IV, diabetic (STZ) + melatonin group (MT). Throughout the experiment, the animals' fasting blood sugar levels were measured. Blood was obtained to determine the animals' cumulative blood sugar levels after sacrification. For histological and morphometrical evaluations, the pancreatic and adrenal gland tissues were dissected and processed. Our results showed that diabetic rats receiving melatonin significantly (P < 0.05) improved their fasting blood sugar and cumulative blood sugar levels compared to the diabetic group not receiving melatonin. Furthermore, histopathological examinations of the pancreatic and adrenal tissues of the diabetic rats indicated the occurrence of severe histopathological and morphometric changes. Morphometric analysis of the adrenals indicated a significant increase (P < 0.05) in the thickness of the cortex zones [zona glomerulosa (ZG), zona fasciculata (ZF), and zona reticularis (ZR)] for the diabetic STZ group compared with other groups, and a significant decrease (P < 0.05) in the diameter of the in adrenal gland medullas in the diabetic STZ rats compared to the other groups. Furthermore, treatment with melatonin restored these changes in both the pancreatic and adrenal gland tissues and produced a significant (P < 0.05) improvement in the cortex and medulla thickness compared to the untreated diabetic rats. Overall, melatonin significantly reduced the hyperglycemic levels of glucose in diabetic rats and reversed the majority of histopathological alterations in the tissues of the pancreas and adrenals, demonstrating its anti-diabetic activity.

Method comparison of Particle Enhanced Immunoturbidimetry (PEIT) with High Performance Liquid Chromatography (HPLC) for glycated hemoglobin (HbA1c) analysis

BACKGROUND AND OBJECTIVE

High Performance Liquid Chromatography (HPLC) technique is considered as a gold standard for HbA1c analysis however all laboratories cannot adopt it due to certain limitations. Our aim was to compare Particle Enhanced Immunoturbidimetry (PEIT) method with High Performance Liquid Chromatography (HPLC) for HbA1c analysis.

METHOD

All blood samples were analyzed by HPLC assay on a Bio-Rad D-10 analyzer and PEIT on an Erba XL-200 analyzer. Precision studies were undertaken and Coefficient of Variation (%CV) calculated. Systemic Error (SE), Random Error (RE) and Total Error (TE_calc) were obtained. The Total Allowable Error (TEa) set by the National Glycohemoglobin Standardization Program (NGSP) for HbA1c is 6%.The acceptable evaluation method is where TE_calc is less than TE_a. RESULTS: The Precision studies were satisfactory with Coefficient of Variation (%CV) being less than 4% for both techniques. Mean HbA1c levels were slightly higher from HPLC than PEIT 9.07 ± 2.23% and 8.93 ± 2.10% respectively, although the difference was minimal. RE was 1.41%, TE_calc was 1.55%, which was less than TEa set by the NGSP. Both methods strongly correlated with the correlation coefficient (r) 0.9716, p < 0.0001.

CONCLUSION

Our study showed HbA1c analysis by PEIT technique is precise, accurate, rapid and convenient and can be employed as an alternative to HPLC technique in countries where cost is a major problem for diagnosis and treatment.

Influence of type 1 diabetes on the postural control of women in the third gestational trimester

BACKGROUND

Diabetes can cause biomechanical alterations that may be responsible for additional changes to those existing in a regular gestational period. The way a maternal body responds when affected by diabetes has not been clearly understood. This study aimed to describe the influence of type 1 diabetes on pregnant women's postural control.

METHODS

Forty pregnant women in their third gestational trimester were allocated in two equal groups - the control group and the type 1 diabetic group. The variables related to postural control and balance were assessed using photogrammetry (head protrusion; cervical lordosis; thoracic kyphosis; lumbar lordosis; pelvic anteversion, knee flexion, tibiotarsal and foot inclination angles were measured), and baropodometry (anteroposterior and mediolateral distance trajectory of the center of pressure, amplitude and average speed of displacement of the center of pressure).

FINDINGS

The results of the type 1 diabetic group showed, in the postural analysis, lower head protrusion and pelvic anteversion angles, while there was higher cervical lordosis, thoracic kyphosis, and lumbar lordosis angles. In the baropodometry, the anteroposterior distance and the amplitude of the center of pressure displacement with eyes open and closed were higher.

INTERPRETATION

The findings suggest that type 1 diabetes mellitus in the third trimester of pregnancy is associated with postural changes, a decrease in the active ankle range of motion and increase in the anteroposterior oscillation of the center of pressure, with negative repercussions for postural control.

Carbohydrate restriction for glycaemic control in Type 2 diabetes: a systematic review and meta-analysis

AIM

To conduct a systematic review and meta-analysis to evaluate the effect of carbohydrate restriction on glycaemic control in Type 2 diabetes.

METHODS

We searched Medline, EMBASE and CINAHL for the period between 1976 and April 2018. We included randomized controlled trials comparing carbohydrate restriction with a control diet which aimed to maintain or increase carbohydrate intake, and that reported HbA_1c as an outcome and reported the amount of carbohydrate consumed during or at the end of the study, with outcomes reported at ≥3 months.

RESULTS

We identified 1402 randomized controlled trials, 25 of which met the inclusion criteria, incorporating 2132 participants for the main outcome. Definitions of low carbohydrate varied among the studies. The pooled effect estimate from meta-analysis was a weighted mean difference of -0.09% [95% CI -0.27, 0.08 (P = 0.30); I² 72% (P <0.001)], suggesting no effect on HbA_1c of restricting the quantity of carbohydrate. A subgroup analysis of diets containing 50-130 g carbohydrate resulted in a pooled effect estimate of -0.49% [95% CI -0.75, -0.23 (P <0.001); I² 0% (P = 0.56)], suggesting a clinically and statistically significant effect on HbA_1c in favour of low-carbohydrate diets in studies of ≤6 months' duration.

CONCLUSIONS

There was no overall pooled effect on HbA_1c in favour of restricting carbohydrate; however, restriction of carbohydrate to 50-130 g per day had beneficial effects on HbA_1c in trials up to 6 months. Future randomized controlled trials should be of >12 months' duration, assess pre-study carbohydrate intake, use recognized definitions of low-carbohydrate diets and examine reasons for non-adherence to prescribed diets in greater detail.

Haemoglobin A1c in the diagnosis and monitoring of diabetes mellitus

Haemoglobin A(1c) (HbA(1c)) is due to celebrate its 40th birthday. Many people would argue that the clinical studies relating the test to diabetes complications while in its late 20s are likely to be its finest ever achievement. However, this article looks at how HbA(1c) has matured since then and discusses in detail how its many strengths and idiosyncrasies as a marker of glycaemic risk have, as a 30-something, become more clearly understood. As HbA(1c) approaches middle age, this paper also describes how the test appears to be developing a mid-life crisis, as debate over how its results should be expressed seems likely to divide opinion among clinicians for some time to come.

Consensus guidelines for glycemic monitoring in type 1/type 2 & GDM

Stringent monitoring of blood glucose in diabetes plays an important role as the treatment of the disease itself. Blood glucose monitoring (BGM) strategies such as measurement of Hb1Ac, Self-Monitoring of Blood Glucose (SMBG) and Continuous Glucose Monitoring (CGM) plays a vital role in achieving the important goal of preventing long term complications of diabetes. Although the use of BGM is recommended by various international guidelines in T1DM and T2DM, there is no consensus on the utility of BGM in India. So, there is a need to develop a guidance for uniform monitoring mechanism among the care givers taking into account the variations and challenges that are unique to Indian population. A committee was established that comprised of physicians, researchers and other healthcare professionals having expertise in diabetes treatment to oversee the formulation of guidelines on different monitoring and treatment aspects of diabetes. Extensive literature searches were conducted to identify and analyze the evidence available on BGM. An initial draft of BGM guidelines was presented to core members who discussed the subject matter and presented their opinion. This was then taken to wider expert audience to invite their comments that were incorporated in the initial draft. The first compilation was presented at a conference attended by nearly 200 experts. Again, their opinion was sought and the next version was prepared which was sent to core committee members for the final inputs. The Indian consensus guideline on BGM using Hb1Ac, SMBG and CGM as the primary tools was then finalized.

Direct diabetes-related costs in young patients with early-onset, long-lasting type 1 diabetes

Objective

To estimate diabetes-related direct health care costs in pediatric patients with early-onset type 1 diabetes of long duration in Germany.

Research Design and Methods

Data of a population-based cohort of 1,473 subjects with type 1 diabetes onset at 0–4 years of age within the years 1993–1999 were included (mean age 13.9 (SD 2.2) years, mean diabetes duration 10.9 (SD 1.9) years, as of 31.12.2007). Diabetes-related health care services utilized in 2007 were derived from a nationwide prospective documentation system (DPV). Health care utilization was valued in monetary terms based on inpatient and outpatient medical fees and retail prices (perspective of statutory health insurance). Multiple regression models were applied to assess associations between direct diabetes-related health care costs per patient-year and demographic and clinical predictors.

Results

Mean direct diabetes-related health care costs per patient-year were €3,745 (inter-quartile range: 1,943–4,881). Costs for glucose self-monitoring were the main cost category (28.5%), followed by costs for continuous subcutaneous insulin infusion (25.0%), diabetes-related hospitalizations (22.1%) and insulin (18.4%). Female gender, pubertal age and poor glycemic control were associated with higher and migration background with lower total costs.

Conclusions

Main cost categories in patients with on average 11 years of diabetes duration were costs for glucose self-monitoring, insulin pump therapy, hospitalization and insulin. Optimization of glycemic control in particular in pubertal age through intensified care with improved diabetes education and tailored insulin regimen, can contribute to the reduction of direct diabetes-related costs in this patient group.

Costs of paediatric diabetes care in Germany: current situation and comparison with the year 2000

AIMS

To estimate direct costs of paediatric Type 1 diabetes care and associated factors in Germany for the year 2007 and to compare results with the costs for the year 2000.

METHODS

Our study includes clinical data and charges for any diabetes-related health care service of 14,185 continually treated subjects with paediatric diabetes aged < 20 years [52.5% male, mean age (SD) 12.1 (4.2) years], derived from a nationwide prospective patient documentation system (DPV). Health-care utilization was valued in monetary terms by using inpatient and outpatient medical fees and retail prices (perspective of the statutory health insurance). Associations between average total diabetes-related costs or various single cost categories per patient and age, sex, migration background, diabetes duration, and metabolic control were analysed by multiple regression procedures and by a two-part model for hospitalization costs. Total direct costs in the whole paediatric diabetes population in Germany were estimated. Mean costs per patient as well as total costs in the German paediatric diabetes population in 2007 were compared to 2000 costs (inflated to the year 2007).

RESULTS

Mean direct diabetes-associated costs per subject were €3524 (inter-quartile range: 1831-4743). Main cost categories were hospitalization (32%), glucose self-monitoring (29%), insulin pump therapy (18%), and insulin (15%). Based on the present estimation, the total costs of paediatric diabetes care in Germany exceeded €110 million in 2007. Compared with estimates of the year 2000, average costs per patient had increased by 20% and total costs for German paediatric diabetes care by 47%.

CONCLUSIONS

Direct costs for paediatric Type 1 diabetes care increased between 2000 and 2007, probably partly because of new therapeutic strategies and an increase in diabetes prevalence.

Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus

BACKGROUND

Multiple laboratory tests are used to diagnose and manage patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these tests varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for the use of laboratory testing for patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. Draft guidelines were posted on the Internet and presented at the 2007 Arnold O. Beckman Conference. The document was modified in response to oral and written comments, and a revised draft was posted in 2010 and again modified in response to written comments. The National Academy of Clinical Biochemistry and the Evidence-Based Laboratory Medicine Committee of the American Association for Clinical Chemistry jointly reviewed the guidelines, which were accepted after revisions by the Professional Practice Committee and subsequently approved by the Executive Committee of the American Diabetes Association.

CONTENT

In addition to long-standing criteria based on measurement of plasma glucose, diabetes can be diagnosed by demonstrating increased blood hemoglobin A(1c) (HbA(1c)) concentrations. Monitoring of glycemic control is performed by self-monitoring of plasma or blood glucose with meters and by laboratory analysis of HbA(1c). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed.

SUMMARY

The guidelines provide specific recommendations that are based on published data or derived from expert consensus. Several analytes have minimal clinical value at present, and their measurement is not recommended.

Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus

BACKGROUND

Multiple laboratory tests are used to diagnose and manage patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these tests varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for the use of laboratory testing for patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. Draft guidelines were posted on the Internet and presented at the 2007 Arnold O. Beckman Conference. The document was modified in response to oral and written comments, and a revised draft was posted in 2010 and again modified in response to written comments. The National Academy of Clinical Biochemistry and the Evidence Based Laboratory Medicine Committee of the AACC jointly reviewed the guidelines, which were accepted after revisions by the Professional Practice Committee and subsequently approved by the Executive Committee of the American Diabetes Association.

CONTENT

In addition to long-standing criteria based on measurement of plasma glucose, diabetes can be diagnosed by demonstrating increased blood hemoglobin A(1c) (Hb A(1c)) concentrations. Monitoring of glycemic control is performed by self-monitoring of plasma or blood glucose with meters and by laboratory analysis of Hb A(1c). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed.

SUMMARY

The guidelines provide specific recommendations that are based on published data or derived from expert consensus. Several analytes have minimal clinical value at present, and their measurement is not recommended.

Frequency of SMBG correlates with HbA1c and acute complications in children and adolescents with type 1 diabetes

The aim of this study was to correlate the frequency of self-monitoring of blood glucose (SMBG) to the quality of metabolic control as measured by hemoglobin A1c (HbA1c), the frequency of hypoglycemia and ketoacidosis, and to see whether the associations between SMBG and these outcomes are influenced by the patient's age or treatment regime. We analyzed data from the DPV-Wiss-database of 26 723 children and adolescents aged 0-18 yr with type 1 diabetes recorded during 1995-2006. Variables evaluated were gender, age at visit, diabetes duration, therapy regime, insulin dose, body mass index-standard deviation scores (BMI-SDS), HbA1c, rate of hypoglycemia, and ketoacidosis. In the youngest age group of children under the age of 6 yr, the frequency of SMBG was the highest compared with that in children aged 6-12 yr or children aged > 12 yr: 6.0/d vs. 5.3/d vs. 4.4/d (p < 0.001). Frequency of SMBG differed significantly also in the different groups of treatment (p < 0.001), but only for the continuous subcutaneous insulin infusion (CSII) group the frequency was considerably higher: 5.3/d (CSII) vs. 4.7/d (multiple daily injections) vs. 4.6/d (conventional therapy). Adjusted for age, gender, diabetes duration, year of treatment, insulin regimen, insulin dose, BMI-SDS, and center difference, SMBG frequency was significantly associated with better metabolic control with a drop of HbA1c of 0.20% for one additional SMBG per day (p < 0.001). Increasing the SMBG frequency above 5/d did not result in further improvement of metabolic control. A higher frequency of SMBG measurements was related to better metabolic control. But only among adolescents aged > 12 yr, metabolic control (HbA1c) improved distinctively with two or more blood glucose measurements.

Investigation of quality of life and family burden issues during insulin pump therapy in children with Type 1 diabetes mellitus--a large-scale multicentre pilot study

AIMS

To investigate psychosocial aspects of continuous subcutaneous insulin infusion (CSII) therapy in children with Type 1 diabetes and to identify relevant and sensitive measures.

METHODS

We performed a multi-centre prospective pre-/post-study with children (53 girls, 64 boys, age 10.5 +/- 3.7 years, mean +/- sd) with Type 1 diabetes and their main carer from 18 German diabetic centres. Twenty-five children aged 8-11 years and 63 adolescents aged 12-16 years and their parents, plus 29 parents of children aged 4-7 years completed standardized questionnaires on generic and diabetes-specific quality of life (QOL), generic parenting stress, mealtime behaviour, fear of hypoglycaemia and family conflict immediately before and 6 months after transition to CSII.

RESULTS

After transition to CSII, diabetes-specific QOL of children increased significantly (P < 0.001) in all age groups, with moderate to large effect sizes (children aged 4-7 years: Cohen's effect sized = 1.3; 8-11 years: d = 0.9, adolescents 12-16 years: d = 0.6). Parents reported reduced frequency (P < 0.01, d = 0.4-0.7) and difficulty (P < 0.01, d = 0.3-0.6) of overall parenting stress and decreased worries about hypoglycaemia (P < 0.01, d = 0.4-0.6). Parents of younger children (4-7 years) reported reduced problems with nutrition management (frequency: P < 0.001, d = 1.1; difficulty: P < 0.05, d = 0.7).

CONCLUSIONS

CSII may have substantial psychosocial benefits. Controlled studies are needed.

Desirable performance standards for HbA(1c) analysis - precision, accuracy and standardisation: consensus statement of the Australasian Association of Clinical Biochemists (AACB), the Australian Diabetes Society (ADS), the Royal College of Pathologists of Australasia (RCPA), Endocrine Society of Australia (ESA), and the Australian Diabetes Educators Association (ADEA)

BACKGROUND

HbA(1c) (glycohaemoglobin) is universally used in the ongoing monitoring of all patients with diabetes. There are many % HbA(1c) target control rating recommendations by national, regional and international expert bodies for diabetes patients and these are variable around the world. General patient target control ratings are currently most often recommended as either <6.5% or <7.0% HbA(1c), with <6.0% HbA(1c) stated for individual patients where clinically possible. This necessitates very precise HbA(1c) assays and the same patient values, irrespective of HbA(1c) method or area of the world.

METHODS

HbA(1c) targets recommended by major expert groups and published HbA(1c) assay precision (coefficient of variation, %CV) levels have been detailed. These have been compared with published biological variation levels and with calculated HbA(1c) error ranges at various HbA(1c) levels and %CV levels. In addition, these have been compared with the analytical precision necessary to differentiate between the upper limit of the normal range for HbA(1c) and targets recommended by expert groups for diabetes control.

RESULTS

Intralaboratory analytical CVs of <2% are necessary and are achievable on automated HPLC analysers, and are supported on grounds of both clinical need and biological variation, as well as the need to differentiate the national, regional and international target recommendations from the upper limit of the normal range (<6.0% HbA(1c) level).

CONCLUSIONS

Routine methods with tight long-term imprecision with CVs of <2% are recommended. International HbA(1c) targets essentially require that all HbA(1c) methods be precise, and have minimal standardisation bias and minimal methodological interferences in individual patients.

Development of a combined setup for simultaneous detection of total and glycated haemoglobin content in blood samples

An original setup for analysis of glycated haemoglobin (HbA1c) in blood is reported. The construction employed a combination of the piezoelectric biosensor for glycated haemoglobin and the flow-through photometric sensor for total haemoglobin (Hb). The modification of gold electrodes with 3-aminophenylboronic acid (APBA) as a specific ligand was studied; the chemisorbed conjugate of APBA with a long-chain thiocompound provided the best affinity for HbA1c. The effect of various operating parameters, such as flow rate and instrumental setup, was optimised. The total haemoglobin content was analysed as absorbance of the haemoglobin-cyanide derivative at 540 nm. Only one standard (calibrator) diluted in various ratio was necessary for calibration and 1 microl of blood was sufficient for analysis. The full range of HbA1c content (4-15%) in blood can be analysed; the working ranges of total and glycated haemoglobin were 50-2000 and 10-90 microg/ml, respectively. The developed method was successfully evaluated on blood samples collected from diabetics.

Severe hypoglycaemia, metabolic control and diabetes management in children with type 1 diabetes in the decade after the Diabetes Control and Complications Trial -- a large-scale multicentre study

Hypoglycaemia is frequently the limiting factor in achieving optimal glycaemic control. Therefore, insulin therapy, the incidence of hypoglycaemia, and glycaemic control were investigated in 6309 unselected children with type 1 diabetes in a large-scale multicentre study. Using standardised computer-based documentation, the incidence of severe hypoglycaemia, HbA1( c) levels, insulin regimen, diabetes duration, and the number of patients attending a treatment centre were investigated for the age groups 0-<5 years ( n =782), 5-<7 years ( n =1053), and 7-<9 years ( n =4474). The average HbA1( c) level was 7.6% (no significant difference between age groups). Young children had more severe hypoglycaemic events (31.2/100 patient years) as compared to older children (19.7; 21.7/100 patient years, P <0.05) independent of the treatment regimen. Our data suggest that diabetes centres treating less than 50 patients per year have a higher incidence of hypoglycaemia in 0-<5-year-old children (43.0/100 patient years) as compared to larger centres (24.1/100 patient years; P <0.0001). Significant predictors of hypoglycaemia were younger age ( P <0.0001), longer diabetes duration ( P <0.0001), higher insulin dose/kg per day ( P <0.0001), injection regimen ( P <0.0005), and centre experience ( P <0.05).

CONCLUSION

Despite modern treatment, young children have an elevated risk for developing severe hypoglycaemia compared to older children, especially when treated at smaller diabetes centres. The therapeutic goal of carefully regulating metabolic control without developing hypoglycaemia has still not been achieved. Further advances in diabetic treatment may result from giving more attention to hypoglycaemia in young children.

Introduction of IFCC reference method for calibration of HbA: implications for clinical care

Abstract HbA(1c) is recommended for monitoring glycaemic control and quantifying the risk of complications in patients with diabetes. National guidelines for treatment of patients with diabetes in UK specify that HbA(1c) measurements should be Diabetes Control and Complications Trial (DCCT)-aligned i.e. comparable to the DCCT and UK Prospective Diabetes Study (UKPDS). The IFCC reference method for HbA(1c) will be introduced in Europe in December 2003 for calibration of all laboratory and POCT (point of care testing) methods for HbA(1c) following the recent EC "In Vitro Diagnostic" (IVD) directive. This reference method involves measurement of HbA(1c) and HbA(0) by electron-spray ionisation-mass spectrometry or capillary electrophoresis with the reference range approximately 2% HbA(1c) lower than the corresponding range from the DCCT. However, this EC IVD directive will not change reporting of DCCT-aligned HbA(1c) in the UK. Professionals involved in the care of patients with diabetes in the UK met with Dr Sue Roberts in London in July 2003. It was decided that in the UK DCCT-aligned HbA(1c) will continue to be reported from December 2003 for patient care and that laboratories currently reporting non-aligned DCCT HbA(1c) should change to reporting DCCT-aligned results as soon as possible. It was considered important for diabetes care in the UK that the reporting of HbA(1c) should not fragment. The UK HbA(1c) Standardization Committee was set up to hold "a watching brief " on HbA(1c) especially with relation to reporting of HbA(1c) in other countries.

Haemoglobin A1c--a marker for complications of type 2 diabetes: the experience from the UK Prospective Diabetes Study (UKPDS)

Haemoglobin A1c (HbA1c) is the pre-eminent factor for quantifying the risk of complications in patients with diabetes and for monitoring glycaemia. Intervention to lower blood glucose in the two landmark clinical trials, the UK Prospective Diabetes Study (UKPDS) and the Diabetes Control and Complications Trial (DCCT), led to a reduction in the microvascular complications of diabetes. Glycaemic status could be compared in the UKPDS and DCCT as the Bio-Rad Diamat HPLC analyser, as used in the DCCT, was introduced in 1989 for measurement of HbA1c in the UKPDS, after liaison with the DCCT. Results from other methods used for measurement of glycated haemoglobin during the UKPDS were aligned to this method. The Bio-Rad Diamat analyser in the central laboratory for the UKPDS, reference range 4.5-6.2% HbA1c, was certified as comparable to the DCCT by the National Glycohemoglobin Standardization Program in 1998. A median difference in HbA1c of 0.9% was maintained over 10 years between the intensively and conventionally treated groups in the UKPDS (7.0% vs. 7.9% HbA1c) despite HbA1c increasing over time. Clinical care was transferred to general practitioners after the end of the main glucose control study for post-study monitoring. Over the first 3 years of post-study monitoring, HbA1c rose slightly in the previously intensively treated group with no appreciable increase in the conventional group, due to intensification of therapy. At near-normal HbA1c, < 6%, the updated mean value chosen to reflect glycaemic exposure throughout the UKPDS, the incidence of myocardial infarction was 2-3 times that of microvascular disease, with similar incidences for both complications at >10% updated mean HbA1c. Relationships between the risk of complications of type 2 diabetes and updated mean HbA1c had no observable thresholds. The UKPDS risk engine derived from the UKPDS database calculates coronary heart disease risk using HbA1c as a continuous variable and could now replace the Framingham equations for patients with type 2 diabetes.

Glycated hemoglobin standardization--National Glycohemoglobin Standardization Program (NGSP) perspective

The Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) demonstrated conclusively that risks for complications in patients with diabetes are directly related to glycemic control, as measured by glycated hemoglobin (GHb). Many diabetes organizations worldwide now recommend GHb targets in terms of DCCT/ UKPDS hemoglobin A1c (HbA1c). However, in 1993 there was a lack of comparability of GHb test results among methods and laboratories that represented a major obstacle to meaningful implementation of specific guidelines for diabetes care. The National Glycohemoglobin Standardization Program (NGSP) was implemented to enable laboratories to report DCCT/UKPDS-traceable GHb/HbA1c results. The number of methods and laboratories certified by the NGSP as traceable to the DCCT has steadily increased. Proficiency testing results show marked improvement in the comparability of GHb results. By the end of 2002, 98% of surveyed laboratories (n = approx. 2000) reported GHb results as HbA1c or equivalent compared to 50% in 1993. Ninety-seven percent of laboratories used an NGSP-certified method. For most certified methods in 2002, between-laboratory CVs were < 5%. For all certified methods in 2002, the mean HbA1c value (%) was within 0.8% HbA1c from the NGSP target at all HbA1c concentrations. The vast majority of laboratories in the US are now reporting results that are traceable to DCCT/UKPDS outcomes.

Issues to consider when attempting to achieve the American Diabetes Association clinical quality requirement for haemoglobin A1c

Diabetes mellitus is a chronic disease that is monitored by measurement of haemoglobin A1c (A1C) as an index of glycaemic control. The limitations of using A1C, given the consensus clinical practice recommendations made by the American Diabetes Association, need to be better understood by clinicians. These include bias between DCCT-aligned methods, analytical variation and intra-individual variation. As intra-individual variation is the principal factor determining variation in A1C in rolling means of the last four A1C results and to stable patients, clinicians may need to monitor A1C more frequently to achieve precise results. Laboratories need to report current values and the analyse six internal quality control specimens for each analytical run. 'Delta check' criteria ought to be applied and results reported to highlight acute deviations in A1C. Such procedures will aid the attainment of the clinical quality requirements and give appropriate results for audit purposes.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

Background: Multiple laboratory tests are used in the diagnosis and management of patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

Approach: An expert committee drafted evidence-based recommendations for the use of laboratory analysis in patients with diabetes. An external panel of experts reviewed a draft of the guidelines, which were modified in response to the reviewers’ suggestions. A revised draft was posted on the Internet and was presented at the AACC Annual Meeting in July, 2000. The recommendations were modified again in response to oral and written comments. The guidelines were reviewed by the Professional Practice Committee of the American Diabetes Association.

Content: Measurement of plasma glucose remains the sole diagnostic criterion for diabetes. Monitoring of glycemic control is performed by the patients, who measure their own plasma or blood glucose with meters, and by laboratory analysis of glycated hemoglobin. The potential roles of noninvasive glucose monitoring, genetic testing, autoantibodies, microalbumin, proinsulin, C-peptide, and other analytes are addressed.

Summary: The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are of minimal clinical value at the present time, and measurement of them is not recommended.

Determination of a diabetes control and complications trial-aligned HbA(1c) reference range in pregnancy

A diabetes control and complications trial (DCCT)-aligned 95% inter-fractile reference range for glycated haemoglobin in non-diabetic pregnancy was determined as 4.1-5.9% (n=493; two-sided 90% confidence intervals around the lower and upper limits are 4.0-4.2% and 5.8-6.0%, respectively).