Statistical Methods for Monitoring the Relationship between the IFCC Reference Measurement Procedure for Hemoglobin A1c and the Designated Comparison Methods in the United States, Japan, and Sweden

Differential impact of glomerular and tubule-interstitial histological changes on kidney outcome between non-proteinuric and proteinuric diabetic nephropathy

BACKGROUND

Studies on kidney function and histological findings in diabetic nephropathy (DN) with low urinary protein (UP) are few. We examined the differential impact of histological changes on kidney outcomes between non-proteinuric and proteinuric DN.

METHODS

Patients diagnosed with DN by renal biopsy during 1981-2014 were divided into non-proteinuric (UP ≤ 0.5 g/day) and proteinuric (UP > 0.5 g/day) DN. The Cox proportional hazard model was used to examine the association of glomerular lesions (GLs) and interstitial fibrosis and tubular atrophy (IFTA) with end-stage kidney disease (ESKD) development after adjusting for relevant confounders.

RESULTS

The non-proteinuric and proteinuric DN groups included 197 and 199 patients, respectively. During the 10.7-year median follow-up period, 16 and 83 patients developed ESKD in the non-proteinuric and proteinuric DN groups, respectively. In the multivariable Cox hazard model, hazard ratios (HRs) [95% confidence intervals (CIs)] of GL and IFTA for ESKD in proteinuric DN were 2.94 [1.67-5.36] and 3.82 [2.06-7.53], respectively. Meanwhile, HRs [95% CIs] of GL and IFTA in non-proteinuric DN were < 0.01 [0-2.48] and 4.98 [1.33-18.0], respectively. IFTA was consistently associated with higher incidences of ESKD regardless of proteinuria levels (P for interaction = 0.49). The prognostic impact of GLs on ESKD was significantly decreased as proteinuria levels decreased (P for interaction < 0.01).

CONCLUSIONS

IFTA is consistently a useful predictor of kidney prognosis in both non-proteinuric and proteinuric DN, while GLs are a significant predictor of kidney prognosis only in proteinuric DN.

Associations of combined polygenic risk score and glycemic status with atrial fibrillation, coronary artery disease and ischemic stroke

BACKGROUND

It is unknown whether high hemoglobin A1c (HbA1c) is associated with increases in the risk of cardiovascular disease among individuals with elevated genetic susceptibility. We aimed to investigate the association between HbA1c and atrial fibrillation (AF), coronary artery disease (CAD), and ischemic stroke according to the polygenic risk score (PRS).

METHODS

The UK Biobank cohort included 502,442 participants aged 40-70 years who were recruited from 22 assessment centers across the United Kingdom from 2006 to 2010. This study included 305,605 unrelated individuals with available PRS and assessed new-onset AF, CAD, and ischemic stroke. The participants were divided into tertiles based on the validated PRS for each outcome. Within each PRS tertiles, the risks of incident events associated with HbA1c levels were investigated and compared with HbA1c < 5.7% and low PRS. Data were analyzed from November 2022 to May 2023.

RESULTS

Of 305,605 individuals, 161,605 (52.9%) were female, and the mean (SD) age was 56.6 (8.1) years. During a median follow-up of 11.9 (interquartile range 11.1-12.6) years, the incidences of AF, CAD, and ischemic stroke were 4.6, 2.9 and 1.1 per 100 person-years, respectively. Compared to individuals with HbA1c < 5.7% and low PRS, individuals with HbA1c ≥ 6.5% and high PRS had a 2.67-times higher risk for AF (hazard ratio [HR], 2.67; 95% confidence interval (CI), 2.43-2.94), 5.71-times higher risk for CAD (HR, 5.71; 95% CI, 5.14-6.33) and 2.94-times higher risk for ischemic stroke (HR, 2.94; 95% CI, 2.47-3.50). In the restricted cubic spline models, while a U-shaped trend was observed between HbA1c and the risk of AF, dose-dependent increases were observed between HbA1c and the risk of CAD and ischemic stroke regardless PRS tertile.

CONCLUSIONS

Our results suggest that the nature of the dose-dependent relationship between HbA1c levels and cardiovascular disease in individuals with different PRS is outcome-specific. This adds to the evidence that PRS may play a role together with glycemic status in the development of cardiovascular disease.

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.

Age at Menopause and the Risk of Stroke: Observational and Mendelian Randomization Analysis in 204 244 Postmenopausal Women

Background Observational studies have shown that women with an early menopause are at higher risk of stroke compared with women with a later menopause. However, associations with stroke subtypes are inconsistent, and the causality is unclear. Methods and Results We analyzed data of the UK Biobank and EPIC-CVD (European Prospective Investigation Into Cancer and Nutrition-Cardiovascular Diseases) study. A total of 204 244 postmenopausal women without a history of stroke at baseline were included (7883 from EPIC-CVD [5292 from the subcohort], 196 361 from the UK Biobank). Pooled mean baseline age was 58.9 years (SD, 5.8), and pooled mean age at menopause was 47.8 years (SD, 6.2). Over a median follow-up of 12.6 years (interquartile range, 11.8-13.3), 6770 women experienced a stroke (5155 ischemic strokes, 1615 hemorrhagic strokes, 976 intracerebral hemorrhages, and 639 subarachnoid hemorrhages). In multivariable adjusted observational Cox regression analyses, the pooled hazard ratios per 5 years younger age at menopause were 1.09 (95% CI, 1.07-1.12) for stroke, 1.09 (95% CI, 1.06-1.13) for ischemic stroke, 1.10 (95% CI, 1.04-1.16) for hemorrhagic stroke, 1.14 (95% CI, 1.08-1.20) for intracerebral hemorrhage, and 1.00 (95% CI, 0.84-1.20) for subarachnoid hemorrhage. When using 2-sample Mendelian randomization analysis, we found no statistically significant association between genetically proxied age at menopause and risk of any type of stroke. Conclusions In our study, earlier age at menopause was related to a higher risk of stroke. We found no statistically significant association between genetically proxied age at menopause and risk of stroke, suggesting no causal relationship.

Klotho and Fibroblast Growth Factor 23 Are Independent of Vitamin D, and Unlike Vitamin D, Are Not Associated With Graft- and Patient Survival After Kidney Transplantation

Short-term survival after kidney transplantation is excellent but long-term survival remains suboptimal. The aim of the study was to explore the relationship between soluble α-Klotho (sKlotho) and intact fibroblast growth factor 23 (iFGF23) measured 8 wk and 1 y posttransplant with long-term graft- and patient survival in a cohort of kidney transplant recipients with deficient and nondeficient vitamin D (25[OH]D) levels.

Methods

Vitamin D, sKlotho, and iFGF23 were measured 8 wk and 1 y posttransplant in 132 recipients transplanted between November 2012 and October 2013.

Results

Of the 132 kidney transplant recipients, 49 had deficient vitamin D levels (<30 nmol/L) and 83 had nondeficient vitamin D levels (≥30 nmol/L) at 8 wk posttransplant. The mean age was 51 y and the median follow-up was 7.4 y. At 1 y posttransplant, vitamin D increased significantly. There were no significant differences in sKlotho or iFGF23 levels between the 2 vitamin D groups neither at 8 wk nor 1 y. sKlotho increased significantly and iFGF23 decreased significantly in the whole cohort. During the follow-up, there were 36 graft losses (27%) and 27 deaths (20%). Ninety-four percent of the transplant recipients with nondeficient vitamin D levels were alive with a well-functioning graft after 5 y using Kaplan-Meier survival estimates, compared with 84% of the patients with deficient vitamin D levels (P = 0.014). Klotho and FGF23 levels did not influence graft- and patient survival.

Conclusions

In this nationwide cohort of kidney transplant recipients, long-term graft- and patient survival were significantly better in patients with vitamin D ≥30 nmol/L 8 wk posttransplant compared with those with vitamin D <30 nmol/L. sKlotho levels increased and iFGF23 levels decreased from 8 wk to 1 y posttransplant. Klotho and FGF23 levels were not associated with graft- and patient survival.

Michaelis-Menten kinetic modeling of hemoglobin A1c status facilitates personalized glycemic control

INTRODUCTION

Discrepancy between measured HbA1c and HbA1c calculated from plasma glucose is associated with higher risk for diabetic complications. However, quantification of this difference is inaccurate due to the imperfect linear conversion models. We propose to introduce a mathematical formula that correlates with the observational data and supports individualized glycemic control.

METHODS

We analysed 175,437 simultaneous plasma glucose and HbA1c records stored in our laboratory database. Employing the Michaelis-Menten (MM) equation, we compared the calculated HbA1c levels to the measured HbA1c levels. Data from patients with multiple records were used to establish the patients' glycemic status and to assess the predictive power of our MM model.

RESULTS

HbA1c levels calculated with the MM equation closely matched the population's average HbA1c levels. The Michaelis constant (Km) had a negative correlation with HbA1c (r2 = 0.403). Using personalized Km values in the MM equation, 85.1% of HbA1c predictions were within 20% error (ADAG calculation: 78.4%). MM prediction also performed better in predicting pathologic HbA1c levels (0.904 AUC vs. 0.849 AUC for ADAG).

CONCLUSION

MM equation is an improvement over linear models and could be readily employed in routine diabetes management. Km is a reliable and quantifiable marker to characterize variations in glucose tolerance.

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.

Glycated albumin and post-transplant diabetes mellitus in kidney transplant recipients

BACKGROUND

Post-transplant diabetes mellitus is one of the most important cardiovascular risk factors after solid organ transplantation. Factors other than hyperglycaemia found in patients post-transplant, affect the level of haemoglobin A_1c (HbA_1c), and new markers of hyperglycaemia are needed. Our aim was to establish a 95% reference interval for glycated albumin in kidney transplant recipients, and to compare glycated albumin concentrations to the diagnostic criteria for diabetes mellitus post-transplant using oral glucose tolerance test and HbA_1c.

METHODS

A total of 341 non-diabetic kidney transplant recipients aged ≥18 years who underwent an oral glucose tolerance test at 8 weeks and 1 year after transplantation were included. Glycated albumin was determined by liquid chromatography coupled with tandem mass spectrometry.

RESULTS

The 95% reference interval for glycated albumin was 8.2 (90% CI: 7.2-8.5) to 12.8% (90% CI: 12.2-13.5) which is not significantly different from our laboratory's 95% reference interval for persons without diabetes. At both 8 weeks and 1 year after transplantation, 35 patients (10.3%) fulfilled one, two or all three diagnostic criteria for diabetes mellitus. One year after transplantation, eight additional patients had glycated albumin concentration >12.8%.

CONCLUSION

Our findings are in accordance with the notion that kidney transplant recipients form glycation end products like normal controls as estimated by glycated albumin and HbA_1c. Further studies should address glycated albumin as a supplemental tool for the diagnosis of post-transplant diabetes mellitus in kidney transplant recipients.

The Effect of Regular Consumption of Reformulated Breads on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Bread is a major source of grain-derived carbohydrates worldwide. High intakes of refined grains, low in dietary fiber and high in glycemic index, are linked with increased risk for type 2 diabetes mellitus (T2DM) and other chronic diseases. Hence, improvements in the composition of bread could influence population health. This systematic review evaluated the effect of regular consumption of reformulated breads on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM. A literature search was performed using MEDLINE, Embase, Web of Science and the Cochrane Central Register of Controlled Trials. Eligible studies employed a bread intervention (≥2 wk) in adults (healthy, at cardiometabolic risk or manifest T2DM) and reported glycemic outcomes (fasting blood glucose, fasting insulin, HOMA-IR, HbA1c, and postprandial glucose responses). Data were pooled using generic inverse variance with random-effects model and presented as mean difference (MD) or standardized MD between treatments with 95% CIs. Twenty-two studies met the inclusion criteria (n = 1037 participants). Compared with "regular" or comparator bread, consumption of reformulated intervention breads yielded lower fasting blood glucose concentrations (MD: -0.21 mmol/L; 95% CI: -0.38, -0.03; I² = 88%, moderate certainty of evidence), yet no differences in fasting insulin (MD: -1.59 pmol/L; 95% CI: -5.78, 2.59; I² = 38%, moderate certainty of evidence), HOMA-IR (MD: -0.09; 95% CI: -0.35, 0.23; I² = 60%, moderate certainty of evidence), HbA1c (MD: -0.14; 95% CI: -0.39, 0.10; I² = 56%, very low certainty of evidence), or postprandial glucose response (SMD: -0.46; 95% CI: -1.28, 0.36; I² = 74%, low certainty of evidence). Subgroup analyses revealed a beneficial effect for fasting blood glucose only among people with T2DM (low certainty of evidence). Our findings suggest a beneficial effect of reformulated breads high in dietary fiber, whole grains, and/or functional ingredients on fasting blood glucose concentrations in adults, primarily among those with T2DM. This trial was registered at PROSPERO as CRD42020205458.

Diet May Moderate the Relationship Between Arterial Stiffness and Cognitive Performance in Older Adults

BACKGROUND

Cognitive decline is influenced by various factors including diet, cardiovascular disease, and glucose control. However, the combined effect of these risk factors on cognitive performance is yet to be fully understood.

OBJECTIVE

The current study aimed to explore the inter-relationship between these risk factors and cognitive performance in older adults at risk of future cognitive decline.

METHODS

The sample comprised 163 (Age: M = 65.23 years, SD = 6.50) participants. Food Frequency Questionnaire data was used to score diet quality and adherence to the Western Style Diet (WSD) and Prudent Style Diet (PSD). Glucose control was gauged by serum levels of glycated hemoglobin (HbA1c) and arterial stiffness was measured using carotid to femoral pulse wave velocity. Cognitive performance was assessed using two subtests of the Swinburne University Computerized Cognitive Assessment Battery (SUCCAB) and Rey's Verbal Learning Test (RVLT).

RESULTS

Diet quality, adherence to the WSD or PSD, and glucose control were not significantly related to cognitive outcomes. However, a significant negative association was found between arterial stiffness and the spatial working memory subtest of SUCCAB (β= -0.21, p <  0.05). Arterial stiffness also significantly interacted with the PSD to impact total recall (F change (1,134) = 5.37, p <  0.05) and the composite score of RVLT (F change (1,134) = 4.03, p <  0.05).

CONCLUSION

In this sample of older adults at risk of cognitive decline, diet alone was not found to predict cognitive performance; however, it was found to moderate the relationship between arterial stiffness and cognition.

Comparison of Turbidimetric Inhibition Immunoassay, High-Performance Liquid Chromatography, and Capillary Electrophoresis Methods for Glycated Hemoglobin Determination

OBJECTIVE

The purpose of this study was to compare the performances of and evaluate the agreement among glycated hemoglobin values analyzed by using National Glycohemoglobin Standardization Program-certified and International Federation of Clinical Chemistry-standardized analyzers.

THIS CROSS-SECTIONAL STUDY WAS CONDUCTED AT THE

Armed Forces Institute of Pathology, Department of Chemical Pathology from March 2019 to May 2019.

METHODS

Glycated hemoglobin (HbA1c) was measured in the blood specimens from 100 patients on an ADVIA 1800 by a turbidimetric inhibitory immunoassay (TINIA), Sebia instrument by electrophoresis, and Bio-Rad Variant II Turbo system by high-performance liquid chromatography (HPLC). Quantitative variables were calculated as the mean ± standard deviation (SD). Precision and method comparisons were carried out according to Clinical and Laboratory Standards Institute recommendations. The results obtained from each analyzer were compared by correlation analysis. Method comparison was done by linear regression and Bland-Altman plots using the SPSS software version 24.

RESULTS

The mean ± SD HbA1c values from TINIA, electrophoresis, and HPLC were 7.188% ± 1.89%, 7.164% ± 1.866%, and 7.160% ± 1.85%, respectively. The between-run coefficients of variation for TINIA, electrophoresis, and HPLC were 0.64%, 0.61%, and 0.60%, respectively. All 3 showed good correlation (TINIA, R2 = .994, P = .00; electrophoresis, R2 = .992, P = 0.00; and HPLC, R2 = .994, P = 0.00).

CONCLUSION

The good clinical agreements of HbA1c and strong correlations between analyzers indicate that these analyzers can be used interchangeably.

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 (TEcalc) 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 TEcalc is less than TEa. 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%, TEcalc 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.

The Effect of Laparoscopic Gastric Bypass Surgery on Insulin Resistance and Glycosylated Hemoglobin A1c: a 2-Year Follow-up Study

BACKGROUND

Bariatric surgery improves insulin sensitivity and secretion in patients with type 2 diabetes, but the effect on patients with prediabetes or even normal glucose tolerance deserves further consideration.

METHODS

Cohort study including patients operated with laparoscopic Roux-en-Y gastric bypass surgery (LRYGB) between November 2012 and June 2017 at the Örebro University Hospital (n = 813) with follow-up of 742 patients 2 years after surgery. Fasting insulin, glucose, glycosylated hemoglobin (HbA1c), and homeostatic model assessment of insulin resistance (HOMA-IR) were analyzed at baseline and 2 years after surgery for patients with overt type 2 diabetes, prediabetes, or non-diabetes.

RESULTS

Fasting insulin levels improved for all groups (diabetics baseline 25.5 mIU/L, IQR 17.5-38.0, 2 years 7.6 mIU/L, IQR 5.4-11.1, p < 0.001; prediabetics baseline 25.0 mIU/L, IQR 17.5-35.0, 2 years 6.7mIU/L, IQR 5.3-8.8, p < 0.001; non-diabetics baseline 20.0 mIU/L, IQR 14.0-30.0, 2 years 6.4 mIU/L, IQR 5.0-8.5, p < 0.001). HbA1c improved in all groups (diabetics baseline 56 mmol/mol, IQR 49-74 [7.3%, IQP 6.6-8.9], 2 years 38 mmol/mol, IQR 36-47 [5.6%, IQR 5.4-6.4], p < 0.001; prediabetics baseline 40 mmol/mol, IQR 39-42 [5.8%, IQR5.7-6.0], 2 years 36 mmol/mol, IQR 34-38 [5.5%, IQR 5.3-5.6], p < 0.001; non-diabetics baseline 35 mmol/mol, IQR 33-37 [5.4%, IQR 5.2-5.5]; 2 years 34 mmol/mol, IQR 31-36 [5.3%, IQR 5.0-5.4], p < 0.001). HOMA-IR improved in all groups (diabetics baseline 9.3 mmol/mol, IQR 5.4-12.9, 2 years 1.9 mmol/mol, IQR 1.4-2.7, p < 0.001; prediabetics baseline 7.0 mmol/mol, IQR 4.3-9.9, 2 years 1.6 mmol/mol, IQR 1.2-2.1, p < 0.001; non-diabetics 4.9 mmol/mol, IQR 3.4-7.3, 2 years 1.4 mmol/mol, IQR 1.1-1.9, p < 0.001).

CONCLUSION

Insulin homeostasis and glucometabolic control improve in all patients after LRYGB, not only in diabetics but also in prediabetics and non-diabetic obese patients, and this improvement is sustained 2 years after surgery.

Renal arteriolar hyalinosis, not intimal thickening in large arteries, is associated with cardiovascular events in people with biopsy-proven diabetic nephropathy

AIMS

Diabetic nephropathy, a pathologically diagnosed microvascular complication of diabetes, is a strong risk factor for cardiovascular events, which mainly involve arteries larger than those affected in diabetic nephropathy. However, the association between diabetic nephropathy pathological findings and cardiovascular events has not been well studied. We aimed to investigate whether the pathological findings in diabetic nephropathy are closely associated with cardiovascular event development.

METHODS

This retrospective cohort study analysed 377 people with type 2 diabetes and biopsy-proven diabetic nephropathy, with a median follow-up of 5.9 years (interquartile range 2.0 to 13.5). We investigated how cardiovascular events were impacted by two vascular diabetic nephropathy lesions, namely arteriolar hyalinosis and arterial intimal thickening, and by glomerular and interstitial lesions.

RESULTS

Of the 377 people with diabetic nephropathy, 331 (88%) and 295 (78%) had arteriolar hyalinosis and arterial intimal thickening, respectively. During the entire follow-up period, those with arteriolar hyalinosis had higher cardiovascular event rates in the crude Kaplan-Meier analysis than those without these lesions (P = 0.005, log-rank test). When fully adjusted for clinically relevant confounders, arteriolar hyalinosis independently predicted cardiovascular events [hazard ratio (HR) 1.99; 95% confidence interval (CI) 1.12, 3.86], but we did not find any relationship between arterial intimal thickening and cardiovascular events (HR 0.89; 95% CI 0.60, 1.37). Additionally, neither glomerular nor interstitial lesions were independently associated with cardiovascular events in the fully adjusted model.

CONCLUSIONS

Arteriolar hyalinosis, but not intimal thickening of large arteries, was strongly associated with cardiovascular events in people with diabetic nephropathy.

The Bone Markers Sclerostin, Osteoprotegerin, and Bone-Specific Alkaline Phosphatase Are Related to Insulin Resistance in Children and Adolescents, Independent of Their Association with Growth and Obesity

BACKGROUND/AIMS

Sclerostin, osteoprotegerin, and bone-specific alkaline phosphatase (B-ALP), which are primarily related to bone metabolism, have been linked with insulin resistance in adults. We aimed to evaluate the association of these markers with growth, obesity, and parameters of insulin resistance in lean and obese children and adolescents.

METHODS

We measured sclerostin, osteoprotegerin, and B-ALP in fasting and oral glucose tolerance test (oGTT) serum samples from 1,325 children and adolescents, and during 24-h profiles and after exercise and glucose exposure in young adults.

RESULTS

In addition to the positive relationship with height standard deviation scores (SDS), sclerostin (r = 0.035, p < 0.001) and B-ALP (r = 0.06, p = 0.028) increased, whereas osteoprotegerin (r = -0.098, p < 0.001) decreased with BMI SDS. Furthermore, B-ALP correlated with fasting- and oGTT-derived markers of glucose and insulin metabolism suggestive of insulin resistance. To evaluate potential confounding diurnal variation of bone markers, we performed 24-h profiles. B-ALP and osteoprotegerin had lower night-time levels. Exercise acutely and transiently increased B-ALP and osteoprotegerin levels, but glucose ingestion had no effect.

CONCLUSIONS

Besides their association with growth, sclerostin and osteoprotegerin levels are altered in childhood obesity. Particularly B-ALP was related to insulin resistance indices. Our findings accent the link between bone, growth, and insulin resistance.

The National Glycohemoglobin Standardization Program: Over 20 Years of Improving Hemoglobin A1c Measurement

BACKGROUND

Measurement of hemoglobin A1c (HbA1c) in the blood is integral to and essential for the treatment of patients with diabetes mellitus. HbA1c reflects the mean blood glucose concentration over the preceding 8 to 12 weeks. Although the clinical value of HbA1c was initially limited by large differences in results among various methods, the investment of considerable effort to implement standardization has brought about a marked improvement in analysis.

CONTENT

The focus of this review is on the substantial progress that has been achieved in enhancing the accuracy and, therefore, the clinical value of HbA1c assays.

SUMMARY

The interactions between the National Glycohemoglobin Standardization Program and manufacturers of HbA1c methods have been instrumental in standardizing HbA1c. Proficiency testing using whole blood has allowed accuracy-based assessment of methods in individual clinical laboratories that has made an important contribution to improving the HbA1c measurement in patient samples. These initiatives, supported by the efforts of the IFCC network, have led to a continuing enhancement of HbA1c methods.

Many of the factors that previously influenced HbA1c results independently of blood glucose have been eliminated from most modern methods. These include carbamylation, labile intermediates, and common hemoglobin variants. Nevertheless, some factors (e.g., race and aging) may alter HbA1c interpretation, but whether these differences have clinical implications remains contentious. HbA1c has a fundamental role in the diagnosis and management of diabetes. Ongoing improvements in HbA1c measurement and quality will further enhance the clinical value of this analyte.

Associations between quality of work features in primary health care and glycaemic control in people with Type 2 diabetes mellitus: A nationwide survey

AIMS

To describe and analyse the associations between primary health care centres' (PHCCs') quality of work (QOW) and individual HbA1c levels in people with Type 2 diabetes mellitus (T2DM).

METHODS

This cross-sectional study invited all 1152 Swedish PHCCs to answer a questionnaire addressing QOW conditions. Clinical, socio-economic and comorbidity data for 230,958 people with T2DM were linked to data on QOW conditions for 846 (73.4%) PHCCs.

RESULTS

Of the participants, 56% had controlled (≤52mmol/mol), 31.9% intermediate (53-69mmol/mol), and 12.1% uncontrolled (≥70mmol/mol) HbA1c. An explanatory factor analysis identified seven QOW features. The features having a call-recall system, having individualized treatment plans, PHCCs' results always on the agenda, and having a follow-up strategy combined with taking responsibility of outcomes/results were associated with lower HbA1c levels in the controlled group (all p<0.05). For people with intermediate or uncontrolled HbA1c, having individualized treatment plans was the only QOW feature that was significantly associated with a lower HbA1c level (p<0.05).

CONCLUSIONS

This nationwide study adds important knowledge regarding associations between QOW in real life clinical practice and HbA1c levels. PHCCs' QOW may mainly only benefit people with controlled HbA1c and more effective QOW strategies are needed to support people with uncontrolled HbA1c.

The National Glycohemoglobin Standardization Program: Over 20 Years of Improving Hemoglobin A1c Measurement

BACKGROUND

Measurement of hemoglobin A1c (HbA_1c) in the blood is integral to and essential for the treatment of patients with diabetes mellitus. HbA_1c reflects the mean blood glucose concentration over the preceding 8 to 12 weeks. Although the clinical value of HbA_1c was initially limited by large differences in results among various methods, the investment of considerable effort to implement standardization has brought about a marked improvement in analysis.

CONTENT

The focus of this review is on the substantial progress that has been achieved in enhancing the accuracy and, therefore, the clinical value of HbA_1c assays.

SUMMARY

The interactions between the National Glycohemoglobin Standardization Program and manufacturers of HbA_1c methods have been instrumental in standardizing HbA_1c. Proficiency testing using whole blood has allowed accuracy-based assessment of methods in individual clinical laboratories that has made an important contribution to improving the HbA_1c measurement in patient samples. These initiatives, supported by the efforts of the IFCC network, have led to a continuing enhancement of HbA_1c methods.Many of the factors that previously influenced HbA_1c results independently of blood glucose have been eliminated from most modern methods. These include carbamylation, labile intermediates, and common hemoglobin variants. Nevertheless, some factors (e.g., race and aging) may alter HbA_1c interpretation, but whether these differences have clinical implications remains contentious. HbA_1c has a fundamental role in the diagnosis and management of diabetes. Ongoing improvements in HbA_1c measurement and quality will further enhance the clinical value of this analyte.

Socioeconomic Disparity in the Prevalence of Objectively Evaluated Diabetes Among Older Japanese Adults: JAGES Cross-Sectional Data in 2010

Background

Studies on sex-specific socioeconomic gradients in objectively evaluated diabetes among older adults are scarce.

Methods

We used cross-sectional data of 9,893 adults aged 65 years and older in Aichi Prefecture without long-term care insurance from the Japan Gerontological Evaluation Study (JAGES) in 2010 (Response rate: 66.3%). We collected demographic, socioeconomic (income, years of education, and longest occupation) and behavioral information using a mail-in self-reported survey. Blood samples for the objectively evaluated diabetes and self-reported medical history were collected at annual municipal health checkups. Poisson regression analysis stratified by sex with multiple imputations was conducted to calculate prevalence ratio and 95% confidence interval.

Results

A clear income gradient in diabetes prevalence was observed among women, from 11.7% in the lowest income quartile (Q1) to 7.8% in the highest (Q4). Among men, the findings were 17.6% in Q1 to 15.1% in Q4. The prevalence ratios for diabetes with incomes Q1 to Q4 were 1.43 (95% confidence interval [CI], 1.07–1.90) for women and 1.16 (95% CI, 0.90–1.50) for men after adjusting for age and other socioeconomic factors. Even after adjusting for marital status, body mass index, other metabolic risk factors, and lifestyle factors, the income-based gradient remained among women. Education and occupation were not significantly associated with diabetes in the study population.

Conclusions

Only women showed an income-based gradient in diabetes. Monitoring income gradient in diabetes is important in public health actions, even in older populations. Future longitudinal and intervention studies should evaluate the causal link of income to diabetes onset, determine the mechanisms of the potential sex differences in the income/diabetes association, and identify ways to mitigate the income-based inequality.

HbA1c method performance: The great success story of global standardization

Diagnosing and monitoring the treatment of people with diabetes is a global issue and uses considerable resources in laboratories and clinics worldwide. Hemoglobin A1c (HbA1c) has been the mainstay of monitoring glycemic control in people with diabetes for many years and more recently it has been advocated as a diagnostic tool for type 2 diabetes mellitus (T2DM). Good analytical performance is key to the successful use of any laboratory test, but is critical when using the test to diagnose disease, especially when the potential number of diagnoses could exceed 500 million people. Very small variations in bias or increased imprecision could lead to either a missed diagnosis or overdiagnosis of the disease and given the scale of the global disease burden, this could mean erroneous categorization of potentially millions of people. Fundamental to good performance of diagnostic testing is standardization, with defined reference materials and measurement procedures. In this review, we discuss the historical steps to first harmonize HbA1c testing, followed by the global standardization efforts and provide an update on the current situation and future goals for HbA1c testing.

Impact of Chronic Kidney Disease on Cardiovascular and Renal Events in Patients Undergoing Percutaneous Coronary Intervention with Everolimus-Eluting Stent: Risk Stratification with C-Reactive Protein

BACKGROUND

Chronic kidney disease (CKD) and inflammation play critical roles in atherosclerosis. There is limited evidence regarding the relationship between CKD and patients receiving second-generation drug-eluting stents for coronary artery disease.

OBJECTIVE

This study aimed to investigate the effect of CKD on cardiovascular and renal events in patients undergoing percutaneous coronary intervention (PCI) with everolimus-eluting stents (EES).

METHODS

We analyzed 504 consecutive patients with stable angina pectoris and significant coronary artery stenosis treated with EES. CKD was defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m2 before coronary angiography. The primary outcome was the occurrence of major adverse renal and cardiovascular events (MARCE) including cardiac death, revascularization, heart failure, cerebral infarction, worsening renal function > 25% from baseline, and renal replacement therapy at 1 year.

RESULTS

Patients were divided into the a MARCE (n = 126) and a non-MARCE (n = 378) group. The incidence of CKD was 51% in all subjects (including those on hemodialysis) and was significantly higher in the MARCE group than in the non-MARCE group (p = 0.00001). Multivariate logistic regression analysis identified that CKD was independently associated with MARCE (adjusted odds ratio 2.03, 95% confidence interval 1.21-3.39, p = 0.007). Patients were divided into four groups based on CKD and C-reactive protein (CRP) level prior to initial coronary angiography. Cox proportional hazards analysis revealed that patients with CKD and high CRP (≥0.3 mg/dL) had the worst prognosis (hazard ratio 4.371, 95% confidence interval 2.634-7.252, p = 0.00001) compared to patients without CKD and with low CRP.

CONCLUSION

CKD combined with CRP predicted more clinical events in patients undergoing PCI with EES.

Genetic analysis of single-minded 1 gene in early-onset severely obese children and adolescents

Background

Inactivating mutations of the hypothalamic transcription factor singleminded1 (SIM1) have been shown as a cause of early-onset severe obesity. However, to date, the contribution of SIM1 mutations to the obesity phenotype has only been studied in a few populations. In this study, we screened the functional regions of SIM1 in severely obese children of Slovak and Moravian descent to determine if genetic variants within SIM1 may influence the development of obesity in these populations.

Methods

The SIM1 promoter region, exons and exon-intron boundaries were sequenced in 126 unrelated obese children and adolescents (2–18 years of age) and 41 adult lean controls of Slovak and Moravian origin. Inclusion criteria for the children and adolescents were a body mass index standard deviation score higher than 2 SD for an appropriate age and sex, and obesity onset at less than 5 years of age. The clinical phenotypes of the SIM1 variant carriers were compared with clinical phenotypes of 4 MC4R variant carriers and with 27 unrelated SIM1 and MC4R mutation negative obese controls that were matched for age and gender.

Results

Seven previously described SIM1 variants and one novel heterozygous variant p.D134N were identified. The novel variant was predicted to be pathogenic by 7 in silico software analyses and is located at a highly conserved position of the SIM1 protein. The p.D134N variant was found in an 18 year old female proband (BMI 44.2kg/m²; +7.5 SD), and in 3 obese family members. Regardless of early onset severe obesity, the proband and her brother (age 16 years) did not fulfill the criteria of metabolic syndrome. Moreover, the variant carriers had significantly lower preferences for high sugar (p = 0.02) and low fat, low carbohydrate, high protein (p = 0.02) foods compared to the obese controls.

Conclusions

We have identified a novel SIM1 variant, p.D134N, in 4 obese individuals from a single pedigree which is also associated with lower preference for certain foods.

Is a hilly neighborhood environment associated with diabetes mellitus among older people? Results from the JAGES 2010 study

BACKGROUND

Although living in a hilly environment may promote muscular activity in the daily lives of residents, and such activity may prevent diabetes mellitus, few studies have focused on the impact of living in a hilly environment on diabetes mellitus. The purpose of this study was to investigate the impact of a hilly neighborhood environment on DM in older people.

METHODS

We used data from the Japan Gerontological Evaluation Study, a population-based, cross-sectional study of individuals aged 65 or older without long-term care needs in Japan, which was conducted in 2010. A total of 8904 participants in 46 neighborhoods had responded to the questionnaire and undergone a health check. Diabetes mellitus was diagnosed as HbA_1c ≥ 6.5% and those undergoing treatment for diabetes mellitus. Poorly controlled diabetes mellitus was diagnosed in those without other chronic diseases who had an HbA_1c > 7.5%, and in those with other chronic diseases if their HbA_1c was >8.0%. Neighborhood environment was evaluated based on the percentage of positive responses in the questionnaire and geographical information system data. A multilevel analysis was performed, adjusted for individual-level risk factors. Furthermore, sensitivity analysis was conducted for those who were undergoing treatment for diabetes mellitus (n = 1007).

RESULTS

After adjustment for other physical environmental and individual covariates, a 1 interquartile range increase (1.48°) in slope in the neighborhood decreased the risk of poorly controlled diabetes mellitus by 18% (odds ratio [OR]: 0.82, 95% confidence interval [CI]: 0.70-0.97). Sensitivity analysis confirmed that larger slopes in the neighborhood showed a significant protective effect against diabetes mellitus among those who were undergoing treatment for diabetes mellitus (OR: 0.73, 95% CI: 0.59-0.90).

CONCLUSION

A hilly neighborhood environment was not associated with diabetes mellitus, but was protective against poorly controlled diabetes mellitus.

Congenital hyperinsulinism and glycogenosis-like phenotype due to a novel HNF4A mutation

AIM

Congenital hyperinsulinism (CHI) and glycogen storage disease (glycogenosis) are both causing hypoglycemia during infancy, but with different additional clinical features and therapeutic approach. We aimed to identify a genetic cause in a child with an ambiguous phenotype.

METHODS AND RESULTS

We present a child with hyperinsulinemic hypoglycemia, physiological 3-OH butyrate, increased triglyceride serum levels, increased level of glycogen in erythrocytes, increased liver transaminases, and increased echogenicity on liver ultrasonography. As both parents of the proband were referred as healthy, we raised a clinical suspicion on glycogenosis with recessive inheritance. However, whole exome sequencing revealed no mutation in genes causing glycogenosis, but a novel heterozygous variant LRG_483t1: c.427-1G>A in the HNF4A gene was identified. Aberrant splicing resulting in in-frame deletion c.429_476del, p.(T144_I159del) was confirmed by sequencing of HNF4A transcripts reverse-transcribed from whole blood RNA. The same variant was found in five of eight tested family relatives (one of them already had diabetes, two had prediabetes). With regard to the results of DNA analysis, we added diazoxide to the therapy. Consequently, the frequency and severity of hypoglycemia in the proband decreased. We have also recommended sulfonylurea treatment after diabetes onset in adult mutation carriers.

CONCLUSIONS

We have identified a novel HNF4A gene mutation in our patient with CHI and glycogenosis-like phenotype. The proband and her family members benefited from the genetic testing by WES method and consequently personalized therapy. Nevertheless, the HNF4A gene testing may be considered in selected CHI cases with glycogenosis-like phenotype prior WES analysis.

Mortality in patients with diabetes mellitus and Addison's disease: a nationwide, matched, observational cohort study

OBJECTIVE

Our hypothesis was that patients with diabetes mellitus obtain an additional risk of death if they develop Addison's disease (AD).

DESIGN AND METHODS

Nationwide, matched, observational cohort study cross-referencing the Swedish National Diabetes Register with Inpatient, Cancer and Cause of Death Registers in patients with diabetes (type 1 and 2) and AD and matched controls with diabetes. Clinical characteristics at baseline, overall, and cause-specific mortality were assessed. The relative risk of death was assessed using a Cox proportional hazards regression model.

RESULTS

Between January 1996 and December 2012, 226 patients with diabetes and AD were identified and matched with 1129 controls with diabetes. Median (interquartile range) follow-up was 5.9 (2.7-8.6) years. When patients with diabetes were diagnosed with AD, they had an increased frequency of diabetes complications, but both medical history of cancer and coronary heart disease did not differ compared with controls. Sixty-four of the 226 patients with diabetes and AD (28%) died, while 112 of the 1129 controls (10%) died. The estimated relative risk increase (hazard ratio) in overall mortality in the diabetes and AD group was 3.89 (95% confidence interval 2.84-5.32) compared with controls with diabetes. The most common cause of death was cardiovascular in both groups, but patients with diabetes and AD showed an increased death rate from diabetes complications, infectious diseases and unknown causes.

CONCLUSIONS

Patients with the rare combination of diabetes and AD showed a markedly increased mortality and died more frequently from infections and unknown causes than patients with diabetes alone. Improved strategy for the management of this combination of metabolic disorders is needed.

Nurse-led patient-centered self-management support improves HbA1c in patients with type 2 diabetes-A randomized study

OBJECTIVES

The aim of this study was to evaluate the effect of a patient-centered self-management support, in type 2 diabetes (T2D) with regard to metabolic changes.

METHODS

182 patients were randomized into group intervention (GI), individual intervention (II) or internal controls (IC). An external control (EC) group was recruited from another county council. The intervention consisted of six sessions that featured themes, which regarded different views of their illness experiences. Data were collected in 2010 and 2011.

RESULTS

HbA1c was significantly decreased at 12-month follow-up with 5mmol/mol in the GI and 4mmol/mol in the II. In the IC group, the HbA1c was close to baseline. The EC group had increased HbA1c, though not significantly. When the HbA1c difference at baseline was adjusted, there was a significant difference between intervention groups and the EC-group.

CONCLUSION

Patient-centered self-management support, led by nurses, can lower HbA1c among patients with type 2 diabetes.

PRACTICE IMPLICATIONS

It is possible to train diabetes specialist nurses in clinical patient-centered care, and simultaneously influence patients' metabolic balance positively.

Considerably decreased risk of cardiovascular disease with combined reductions in HbA1c, blood pressure and blood lipids in type 2 diabetes: Report from the Swedish National Diabetes Register

OBJECTIVES

Assess the effect of risk factors changes on risk for cardiovascular disease and mortality in patients with type 2 diabetes selected from the Swedish National Diabetes Register.

METHODS

Observational study of 13,477 females and males aged 30-75 years, with baseline HbA1c 41-67 mmol/mol, systolic blood pressure 122-154 mmHg and ratio non-HDL:HDL 1.7-4.1, followed for mean 6.5 years until 2012. Four groups were created: a reference group (n = 6757) with increasing final versus baseline HbA1c, systolic blood pressure and non-HDL:HDL cholesterol during the study period, and three groups with decreasing HbA1c (n = 1925), HbA1c and systolic blood pressure (n = 2050) or HbA1c and systolic blood pressure and non-HDL:HDL (n = 2745).

RESULTS

Relative risk reduction for fatal/nonfatal cardiovascular disease was 35% with decrease in HbA1c only (mean 6 to final 49 mmol/mol), 56% with decrease in HbA1c and systolic blood pressure (mean 12 to final 128 mmHg) and 75% with combined decreases in HbA1c, systolic blood pressure and non-HDL:HDL (mean 0.8 to final 2.1), all p < 0.001 adjusting for clinical characteristics, other risk factors, treatments and previous cardiovascular disease. Similar risk reductions were found for fatal/nonfatal coronary heart disease, fatal cardiovascular disease, all-cause mortality and also in a subgroup of 3038 patients with albuminuria.

CONCLUSION

Considerable risk reductions for cardiovascular disease and mortality were seen with combined long-term risk factor improvement.

Quality of HbA1c Measurement in Trinidad and Tobago

BACKGROUND

Monitoring of HbA1c is the standard of care to assess diabetes control. In Trinidad & Tobago (T&T) there are no existing data on the quality of HbA1c measurement. Our study examined the precision and accuracy of HbA1c testing in T&T.

METHODS

Sets of 10 samples containing blinded duplicates were shipped to laboratories in T&T. This exercise was repeated 6 months later. Precision and accuracy were estimated for each laboratory/method.

RESULTS

T&T methods included immunoassay, capillary electrophoresis, and boronate affinity binding. Most, but not all, laboratories demonstrated acceptable precision and accuracy.

CONCLUSIONS

Continuous oversight of HbA1c testing (eg, through proficiency testing) in T&T is recommended. These results highlight the lack of oversight of HbA1c testing in some developing countries.

Analysis and Quantitation of Glycated Hemoglobin by Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry

Measurement of glycated hemoglobin is widely used for the diagnosis and monitoring of diabetes mellitus. Matrix assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) analysis of patient samples is used to demonstrate a method for quantitation of total glycation on the β-subunit of hemoglobin. The approach is accurate and calibrated with commercially available reference materials. Measurements were linear (R(2) > 0.99) across the clinically relevant range of 4% to 20% glycation with coefficients of variation of ≤ 2.5%. Additional and independent measurements of glycation of the α-subunit of hemoglobin are used to validate β-subunit glycation measurements and distinguish hemoglobin variants. Results obtained by MALDI-TOF MS were compared with those obtained in a clinical laboratory using validated HPLC methodology. MALDI-TOF MS sample preparation was minimal and analysis times were rapid making the method an attractive alternative to methodologies currently in practice.

A Simple and Easy Process for the Determination of Estimated Plasma Glucose Level in Patients Presenting to Hospital: An Example of Multicentric Data Mining

The aim of the present study was to determine the relation between the simultaneous fasting plasma glucose level and HbA1c in a large population of patients presenting to the hospital, based on various measurement methods available for HbA1c. HbA1c levels of 162,210 patients presenting to various hospitals and laboratories were measured based on seven different systems, and at the same time, eAG levels were calculated based on HbA1c levels. The correlation coefficients (r) between serum plasma glucose and HbA1c levels were found to be 0.809, 0.774, 0.779, 0.817, 0.704, 0.796, and 0.747 in Bio-Rad Variant II, Tosoh G8, ADAMS A1c, Trinity Boronate Affinity, Chromsystems HPLC, Roche Tina-quant, and Abbott Architect, respectively. The concordance correlation coefficients between the eAG levels as calculated with the formulas provided in the text and the eAG levels as calculated according to NGSP directions (where eAG = (28.7*HbA1c) - 46.7) were found to be between 0.9339 and 0.9866. Despite the progress made for the standardization of HbA1c measurements, the relation between serum glucose and HbA1c still demonstrated certain discrepancies pertaining to the differences in measurement methodologies. As a conclusion, each laboratory could determine different eAG levels depending on the data originated by their individual analyzer.

Standardising HbA1c-based diabetes diagnosis: opportunities and challenges

Globally, the incidence of diabetes mellitus is rising at an alarming rate and has become a health crisis that threatens the economies of all nations. Therefore, diagnosing diabetes has become an important issue in the management of diabetes. Glycated hemoglobin (HbA1c) is now recommended as a means to diagnose diabetes, but its use still has limitations. In this article, the biology, measurement, standardization, and opportunities and challenges of the use of HbA1c to diagnose diabetes are reviewed. More specifically, its use in China and the Asian region is discussed in detail.

Cardiovascular disease and mortality in patients with type 2 diabetes after bariatric surgery in Sweden: a nationwide, matched, observational cohort study

BACKGROUND

In patients with diabetes and obesity specifically, no studies have examined mortality after bariatric surgery. We did a nationwide study in Sweden to examine risks of cardiovascular disease and mortality in patients with obesity and diabetes who had undergone bariatric surgery (Roux-en-Y gastric bypass [RYGB]).

METHODS

In this nationwide, matched, observational cohort study, we merged data for patients who had undergone RYGB registered in the Scandinavian Obesity Surgery Registry with other national databases, and identified matched controls (on the basis of sex, age, BMI, and calendar time [year]) who had not undergone bariatric surgery from the National Diabetes Registry. We assessed risks of cardiovascular disease and death using a Cox proportional-hazards regression model and other methods to examine the treatment effect while accounting for residual confounding. Primary outcomes were total mortality, cardiovascular death, and fatal or non-fatal myocardial infarction.

FINDINGS

Between Jan 1, 2007, and Dec 31, 2014, we obtained data for 6132 patients who had undergone RYGB and 6132 control patients who had not. Median follow-up was 3·5 years (IQR 2·1-4·7). We noted a 58% relative risk reduction (hazard ratio [HR] 0·42, 95% CI 0·30-0·57; p<0·0001) in overall mortality in the RYGB group compared with the controls. The risk of fatal or non-fatal myocardial infarction was 49% lower (HR 0·51, 0·29-0·91; p=0·021) and that of cardiovascular death was 59% lower (0·41, 0·19-0·90; p=0·026) in the RYGB group than in the control group. 5 year absolute risks of death were 1·8% (95% CI 1·5-2·2) in the RYGB group and 5·8% (5·0-6·8) in the control group.

INTERPRETATION

Our findings provide support for the benefits of RYGB surgery for patients with obesity and type 2 diabetes. The causes of these beneficial effects may be the weight reduction per se, changes in physiology and metabolism, improved care and treatment, improvements in lifestyle and risk factors, or combinations of these factors.

FUNDING

Swedish Association of Local Authorities and Regions and Region Västra Götaland.

Insulin pump therapy, multiple daily injections, and cardiovascular mortality in 18,168 people with type 1 diabetes: observational study

OBJECTIVE

To investigate the long term effects of continuous subcutaneous insulin infusion (insulin pump therapy) on cardiovascular diseases and mortality in people with type 1 diabetes.

DESIGN

Observational study.

SETTING

Swedish National Diabetes Register, Sweden 2005-12.

PARTICIPANTS

18,168 people with type 1 diabetes, 2441 using insulin pump therapy and 15,727 using multiple daily insulin injections.

MAIN OUTCOME MEASURES

Cox regression analysis was used to estimate hazard ratios for the outcomes, with stratification of propensity scores including clinical characteristics, risk factors for cardiovascular disease, treatments, and previous diseases.

RESULTS

Follow-up was for a mean of 6.8 years until December 2012, with 114,135 person years. With multiple daily injections as reference, the adjusted hazard ratios for insulin pump treatment were significantly lower: 0.55 (95% confidence interval 0.36 to 0.83) for fatal coronary heart disease, 0.58 (0.40 to 0.85) for fatal cardiovascular disease (coronary heart disease or stroke), and 0.73 (0.58 to 0.92) for all cause mortality. Hazard ratios were lower, but not significantly so, for fatal or non-fatal coronary heart disease and fatal or non-fatal cardiovascular disease. Unadjusted absolute differences were 3.0 events of fatal coronary heart disease per 1000 person years; corresponding figures were 3.3 for fatal cardiovascular disease and 5.7 for all cause mortality. When lower body mass index and previous cardiovascular diseases were excluded, results of subgroup analyses were similar to the results from complete data. A sensitivity analysis of unmeasured confounders in all individuals showed that an unmeasured confounders with hazard ratio of 1.3 would have to be present in >80% of the individuals treated with multiple daily injections versus not presence in those treated with pump therapy to invalidate the significantly lower hazard ratios for fatal cardiovascular disease. Data on patient education and frequency of blood glucose monitoring were missing, which might have influenced the observed association.

CONCLUSION

Among people with type 1 diabetes use of insulin pump therapy is associated with lower cardiovascular mortality than treatment with multiple daily insulin injections.

[The glycated hemoglobin: indication, interpretation and limitations]

HbA1c is defined by the slow and irreversible binding of glucose to the N-terminal valine of one or both of the beta chains of hemoglobin A (HbA). It is a marker that is becoming increasingly important because of its role in both the diagnosis and monitoring of diabetic patients with type 1 and type 2. It reflects glycemic control of two or three months. Learned societies such as the IFCC and NGSP contributed to its standardization, which allows inter-laboratory comparison of results. Its assay uses chromatographic, electrophoretic or immunochemical methods. The HbA1c concentration is expressed in percent and in mmol/mol, and a number that is between 4 and 6% (20 and 42mmol/mol) is desirable. However, HbA1c cannot be used in some cases and fructosamine assay must be considered.

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

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

Glucagon-like peptide-1 and blood pressure in young and healthy adults from the general population

Hypertension and diabetes mellitus are highly correlated, but the underlying mechanisms are only partly understood. Therefore, the aim of our study was to investigate the relationships between plasma levels of glucagon-like peptide-1, a key factor in the regulation of glucose homeostasis, and various blood pressure indices. Healthy adults aged 25 to 41 years were enrolled in a population-based study. Established cardiovascular disease, diabetes mellitus, or a body mass index >35 kg/m(2) were exclusion criteria. Fasting plasma glucagon-like peptide-1 levels as determined with a novel high-sensitive assay and ambulatory blood pressure data were available in 1479 participants not using antihypertensive treatment. Median age of our population was 38 years. Mean systolic and diastolic blood pressure across increasing glucagon-like peptide-1 quartiles were 120.6, 122.8, 123.2, and 124.9 mm Hg and 77.1, 78.7, 78.9, and 79.9 mm Hg, respectively. We found a linear relationship of glucagon-like peptide-1 with 24-hour ambulatory blood pressure after multivariable adjustment (β per 1 log-unit increase 2.01; 95% confidence interval, 1.02-3.00; P<0.0001 for systolic and 1.22; 0.47-1.97; P=0.002 for diastolic blood pressure). In separate analyses, glucagon-like peptide-1 was significantly related to both awake (β per 1 log-unit increase 2.05; 1.02-3.09; P=0.0001 for systolic and 1.15; 0.35-1.96; P=0.005 for diastolic blood pressure) and asleep blood pressure (β per 1 log-unit increase 1.34; 0.26-2.42; P=0.01 for systolic and 1.05; 0.26-1.84; P=0.009 for diastolic blood pressure). In conclusion, plasma levels of glucagon-like peptide-1 are significantly associated with both systolic and diastolic blood pressure levels.

The utility of urinary myo-inositol as a marker of glucose intolerance

OBJECTIVE

The most common screening tests for glucose intolerance are fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c). Because it reflects the current status of hyperglycemia, urinary myo-inositol (UMI) may be useful. We evaluated UMI as a screening tool for glucose intolerance.

DESIGN AND METHODS

A cross-sectional, community-based population study of 1057 Japanese residents. 173 with an FPG level between 5.5 and 6.9 mmol/L and an HbA1c under 6.5% had an oral glucose tolerance test. We measured UMI level before (fasting UMI) and 2h after (2h-UMI) glucose ingestion. Δ-UMI was defined as the difference between fasting UMI and 2h-UMI.

RESULTS

Δ-UMI, 2h-UMI and HbA1c levels significantly increased as glucose intolerance worsened. Δ-UMI level was significantly positively correlated with 2h-UMI level (r=0.896, p<0.001). Using cutoff levels from receiver operating characteristic (ROC) analyses, the sensitivity of Δ-UMI (82.1%) and 2h-UMI (79.3%) were higher than that of HbA1c (48.3%). The area under the ROC curve values for Δ-UMI (0.903) and 2h-UMI (0.891) were higher than that for HbA1c (0.785).

CONCLUSIONS

2h-UMI is useful as a non-invasive screening of glucose intolerance.

Albuminuria and renal function as predictors of cardiovascular events and mortality in a general population of patients with type 2 diabetes: a nationwide observational study from the Swedish National Diabetes Register

OBJECTIVE

Reduced renal function and albuminuria predict cardiovascular (CV) events and mortality in type 2 diabetes (T2D). In addition, we evaluated the role of co-existing congestive heart failure (CHF) and other CV risk factors on CV events in a large observational population-based cohort of T2D patients.

RESEARCH DESIGN AND METHODS

We included 66,065 patients with T2D who were reported to the National Diabetes Register (NDR) in Sweden between 2003-2006 with a follow-up of 5.7 years. Data on outcomes were collected from the cause of death and hospital discharge registers.

RESULTS

A total of 10% of patients experienced a CV event and 3.7% of these were fatal. Increasing levels of albuminuria and renal impairment were independently associated with increasing risk of CV events and all-cause mortality also when adjusting for CHF. In normoalbuminuric patients, a reduction in renal function is an important predictor of CV events and all-cause mortality. Glycaemic control (high HbA1c), smoking and hyperlipidaemia had important effects on risk for CV events in patients with albuminuria, while high blood pressure, but not glycaemic control, had an effect in patients with normoalbuminuric renal impairment.

CONCLUSION

Albuminuria and renal impairment are independent risk factors for CV outcomes and mortality in T2D, albuminuria being the strongest risk factor and relevant at all levels of renal function. In normoalbuminuric patients, a reduction in renal function is an important predictor of CV events and all-cause mortality.

Evaluation of turbidimetric inhibition immunoassay (TINIA) and HPLC methods for glycated haemoglobin determination

BACKGROUND

Various factors may affect the accuracy of hemoglobin (Hb) A1c measurements that are widely used to monitor glycemic control in diabetic patients. This study was aimed to compare the values of HbA1c obtained by two different methods, Roche Tina-quant second and thirdgeneration HbA1c assays based on the turbidimetric inhibition immunoassay (TINIA), and high-performance liquid chromatography (HPLC) cation-exchange method used by Arkray Adams HA-8160 analyzer.

METHODS

Measurements of HbA1c were carried out in blood samples from 2,917 patients using above-mentioned methods. Linear regression was used for the correlation analysis and linear equations. Bland-Altman plots were performed from method comparison data using MedCalc statistical software.

RESULTS

For the low control, the second generation Tina-quant assay had within-run and between-run CVs 0.8% and 0.9%; for the high control within-run and between-run CVs were 1% and 0.96%, respectively. HPLC method for the low control had within-run CV 1% and between-run CV 1.3%; for the high control within-run CV was 0.6% and between-run CV was 0.9%.

CONCLUSION

There was a good concordance between the results of TINIA and HPLC methods (y = 1.091x - 0.363; r(2) = 0.96).

The serum undercarboxylated osteocalcin level and the diet of a Japanese population: results from the Kyushu and Okinawa Population Study (KOPS)

The elevated serum undercarboxylated osteocalcin (ucOC) level is related to osteoporosis. In Japan, vitamin K intake is lower, and the incidence of hip fractures noticeably higher in northern Kyushu than in other areas. The study was done to determine the serum ucOC levels in a Japanese population and its association with diet and glucose metabolism. The data of 3,658 healthy adults aged 40-69 (1,373 men and 2,285 women) who lived in northern Kyushu area were analyzed. The data included anthropometric measurements and a self-reported personal interview on daily intake of foods. The serum ucOC level of each participant was measured by electrochemiluminescence immunoassay. Glycohemoglobin A1c (HbA1c), fasting plasma glucose, and serum insulin concentrations were measured. The median serum ucOC level of the women (4.65 ng/mL) was significantly higher than that of the men (3.04 ng/mL) (P = 0.0021). The age-specific ucOC levels of the men decreased significantly with age. In contrast, the ucOC levels of the women aged ≥50 were elevated, but the levels varied markedly within the other age groups. For both men and women, multivariate analysis identified a daily diet rich in vitamin K and HbA1c level as independently having a significant, negative relationship to serum ucOC level. Our study indicates that the serum ucOC decreases with age in men, increases postmenopausally in women, and correlates inversely with dietary consumption of certain foods and with fasting glucose and HbA1c level.

Haemoglobin A1c: Historical overview and current concepts

Since the discovery of the relation between increased concentrations of fast haemoglobin fractions in patients with diabetes mellitus compared to concentrations in subjects without diabetes mellitus by Samuel Rahbar and co-workers in 1969, glycated haemoglobin A1c (HbA1c) has become a "gold standard" for glucose management in patients with diabetes mellitus. Recently, HbA1c has been advocated as a diagnostic marker for diabetes mellitus, which further underlines the importance of HbA1c. There are currently more than 30 methods available on the market with an analytical performance ranging from poor to state of the art. This review describes the biochemistry of HbA1c and the concepts of analytical and biological variation with respect to the measurement of HbA1c. Subsequently, aspects regarding the discovery of HbA1c are described. In addition, an overview is given on the assays methods that are currently available for the measurement of HbA1c. Finally, recommendations for the minimally required analytical performance characteristics of the current HbA1c assays are presented.

Ascorbic acid alleviates toxicity of paclitaxel without interfering with the anticancer efficacy in mice

Paclitaxel is used extensively as a chemotherapeutic agent against a broad range of tumors but often leads to the early termination of treatment due to severe toxic side effects. In this study, we hypothesized that ascorbic acid could reduce the toxic side effects without interfering with the anticancer effect of paclitaxel. To demonstrate this, we examined the effect of the combinational treatment of ascorbic acid and paclitaxel using H1299 (a non-small cell lung cancer cell line) and BALB/c mice implanted with or without sarcoma 180 cancer cells. In H1299 cells, the anticancer effects of the combinational treatment with paclitaxel and ascorbic acid were up to 1.7-foldhigher than those of single-agent paclitaxel treatment. In addition, it was shown that the viability of the HEL299 normal cells was up to 1.6-fold higher with the combinational treatment than with paclitaxel treatment alone. In vivo mouse experiments also showed that mice co-treated with paclitaxel and ascorbic acid did not exhibit the typical side effects induced by paclitaxel, such as a reduction in the numbers of white blood cells and red blood cells and the level of hemoglobin (P < .05). The analysis of cancer-related gene expression by quantitative real-time polymerase chain reaction and immunohistochemistry revealed that the combinational treatment suppressed cancer cell multiplication. Taken together, these results suggest that combinational chemotherapy with ascorbic acid and paclitaxel not only does not block the anticancer effects of paclitaxel but also alleviates the cytotoxicity of paclitaxel in vivo and in vitro.

Time trends in absolute and modifiable coronary heart disease risk in patients with Type 2 diabetes in the Swedish National Diabetes Register (NDR) 2003-2008

AIMS

The aim was to evaluate treatment goal achievements early in the course of Type 2 diabetes, and their effect on 10-year risk of coronary heart disease in patients receiving usual care.

METHODS

Assessment of risk factor control 3 years after diagnosis in patients with Type 2 diabetes with no previous coronary heart disease included from the Swedish National Diabetes Register; a total of 19,382 patients (mean age 58 years) in cross-sectional surveys from 2003 to 2008, and a subgroup of 4293 patients followed individually from year of diagnosis to follow-up after a mean 2.6 years. Estimation of absolute 10-year risk of coronary heart disease using the U.K. Prospective Diabetes Study risk engine, and modifiable 10-year risk defined as percentage excess risk above patients with 'normal' risk factor values.

RESULTS

Treatment goals for HbA1c , blood pressure, total and LDL cholesterol were achieved in 78.4, 65.5, 55.6% and 61.0%, respectively, in the cross-sectional survey in 2008, following a trend of generally improved control. In the individually followed patients in the subgroup, mean absolute 10-year coronary heart disease risk increased from 13.7% (men/women 16.9/9.5%) to 14.2 (men/women 17.6/9.6%) (P < 0.001) from year of diagnosis to follow-up after 2.6 years, while mean modifiable risk decreased from 37.7% (men/women 28.6/49.9%) to 19.1% (13.2/26.9%) (P < 0.001 in all).

CONCLUSIONS

A high achievement of treatment goals and a low mean modifiable 10-year coronary heart disease risk was found at the 3-year follow-up, both in the cross-sectional survey in 2008 and in patients individually followed since diagnosis. This indicates the feasibility and significance of early multifactorial risk factor treatment.