| Diabetes mellitus is characterized as a metabolic disease of chronic hyperglycemia due to insulin secretory insufficiency and/or insulin resistance. Hyperglycemia injuries to body through chronic persistent and fluctuant high glucose levels. Glycated albumin(GA) reflects mean glucose level in preceding 2-3 weeks and is well known to assess recent glucose control and glucose variety in patients with diabetes. This study has three sections to investigate the clinical utility of GA, including use of GA to distinguish occult diabetes from stress-induced hyperglycemia, the clinical use of GA in gestational diabetes mellitus, and the predictive value of GA to diabetic retinopathy,.Section 1. Use of glycated albumin to distinguish occult diabetes mellitus from stress-induced hyperglycemia in Chinese orthopedic trauma patientsObjective Some non-diabetic trauma patients with hyperglycemia have been found to have occult diabetes mellitus(ODM). We studied whether glycated albumin(GA) was an effective tool for detecting ODM in orthopedic trauma patients with elevated glucose levels.Method After obtaining approval from local ethnic committee, a cross-sectional, sequential case series study of adult patients(≥18 years of age) presenting to Orthopaedic Trauma Center from September 2009 to March 2010 for new limb fracture, was performed. Hemoglobin A1 c and GA level were measured in the hyperglycemic patients with no prior diabetes mellitus. Receiver operating characteristic(ROC) curve was plotted to examine the sensitivity, specificity, positive and negative predictive value of GA in identifying occult diabetes from hospitalized acute hyperglycemia.Result A total of 2,058 trauma patients were screened and 399 patients(19.4%) with no known diabetes mellitus were noted to be hyperglycemic. Of these 399 patients, 38.3%(n 153) had ODM according to the Hb A1 c diagnosis cutoff point. GA level was strongly correlated with Hb A1 c using Pearson’s correlation analysis(r=0.887, p < 0.01). Using logistic regression analysis, GA(odds ratio [OR]=1.60, p< 0.001) and fasting plasma glucose(OR =1.974, p< 0.001) were identified as significant risk factors for the diagnosis of ODM. Receiver operating characteristic curve analysis showed that a GA value of 17.5% gave an optimal sensitivity of 73.20% and specificity of 99.12% for distinguishing ODM from stress-induced hyperglycemia.Conclusion The hyperglycemia presented in the orthopaedic trauma population should not solely be attributed to the stress-induced metabolic response to injury. Our study demonstrates that almost 40% of presumably non-diabetic trauma patients presenting with hyperglycemia were found to have ODM in newly orthopaedic trauma patients. A GA value of 17.5%, the optimal cut-off point, could distinguish between ODM and stress-induced hyperglycemia in Chinese orthopaedic trauma subjects. It is necessary to determine the association of expanded ODM detecting by GA measurement with decrease of infection risk and long-term health outcomes in trauma patients.Section 2. The value of glycated albumin in screening for gestational diabetes mellitus in pregnant womenObjective To assess the value of glycated albumin in screening for gestational diabetes mellitus in pregnant women and to examine the differential effects of insulin sensitivity and secretion on hemoglobin A1c(Hb A1c) and glycated albumin(GA) at 24–32 weeks of pregnancy in women with gestational diabetes mellitus(GDM).Methods A cross-sectional, sequential case series study of pregnancy women with age from 20 to 35 years presenting to the obstetric clinics between January, 2011 and May, 2012 was performed. The women at 24-28 weeks’ gestation with abnormal 50 g oral glucose screening test(1h post-load glucose≥7.2mmol/L) underwent 75 g oral glucose tolerance test(OGTT) after an 8-h overnight fasting within a week. Hb A1 c and GA measurements were implemented in OGTTs. The homeostasis modeling assessment of insulin resistance(HOMA-IR), HOMA-%β,ISOGTT,and modified insulinogenic index were calculated to access insulin sensitivity and secretory function.Results A total of 101 gravidas were analyzed in the present study, including 297 subjects with GCT(-) 243 GDM and 470 subjects with GCT(+)/OGTT(-). GDM group and GCT(+)/OGTT(-) group had higher level of age, BMI(recruitment and pre-pregnancy), GA and FPG(P<0.01). ROC ananlysis showed that AUC of GA to screening for GCT(+) is 0.772(0.739-0.805). The sensitivity and specificity of GA≥10.85% to detect GCT(+) is 89.5% and 52.8%. In the population of GCT(+), GDM group had higher level of age, BMI(recruitment and pre-pregnancy), systolic pressure, diastolic pressure, hemoglobin A1 c, GA, 0-min plasma glucose(PG), 30-min PG, 60-min PG and 120-min PG compared with non-GDM group(P<0.01). With respect to insulin sensitivity and secretory indices, GDM group had lower level of ISOGTT and insulinogenic index, and higher level of HOMA-IR(P<0.01). Hb A1 c was positively correlated with BMI(r=0.338, P<0.01), systolic pressure(r=0.232, P<0.01), diastolic pressure(r=0.322, P<0.01), HOMA-IR(r=0.350, P<0.01). GA had negative correlation with Δ I0-30/Δ G0-30(r=-0.219, P=0.001) and HOMA-%β(r=-0.171, P=0.01). GA showed stronger correlation with glucose levels at OGTT than Hb A1 c. Multiple regression analyses observed that diastolic pressure(β =0.195, P=0.031), 0-min PG(β =0.248, P=0.001), 120-min PG(β = 0.213, P=0.000) and HOMA-IR(β=0.195, P=0.003) were independently significant in the equation with Hb A1 c as dependent variable. 0-min PG(β =0.430, P=0.000) and 120-min PG(β = 0.311, P=0.000) were found to be independent explanatory variables for GA.Conclusion GA is not a suitable glycemic index for gestational diabetes melluts screening. GA might be an alternative index for 50 g glucose screening. GA is closely correlated with early-phase insulin secretory function but not with insulin resistance. Insulin secretoy impairement, but not insulin resistance, might influence the postprandial glucose level and result in a greater increase in GA over Hb A1 c. We suggested that GA might be a better monitoring index in GDM patients treated with insulin or diet.Section 3. Serum glycated albumin predicts the progression of diabetic retinopathy—a five year retrospective longitudinal studyObjective Diabetic retinopathy(DR) is a major microvascular complication in type 2 diabetes and can lead to the consequence of blindness. Among the known mechanism of DR, advanced glycated end products(AGEs) mediated vascular inflammation has been confirmed to cause endothelial injuries. In this study, we hypothesized that, in addition to poor glycemic control, a higher glycation index of GA might also predict or influence an onset or a progression of DR. According to this hypothesis, we aimed to characterize and compare the associations of Hb A1 c and GA with a progression of diabetic retinopathy in a hospital-based population of type 2 diabetes.Methods In this retrospective longitudinal study, we enrolled the subjects with type 2 diabetes who had undergone fundus photography twice with a 5-years gap between January 2006 and December 2012, and had been measured consecutively for hemoglobin A1c(Hb A1c) and GA levels every 3 or 6 months. The subjects were divided into two groups with or without a progression of DR. The mean Hb A1 c and mean GA were calculated separately by the sum of all measured values divided by the numbers of values throughout the study period.Results Of the 359 subjects, progression group showed significantly higher diabetes duration(8.41 ± 5.72 vs.6.46 ± 5.77, P<0.01), baseline Hb A1c(9.13 ± 2.71 vs. 8.41 ± 2.32, P <0.05), fasting plasma glucose(8.71 ± 2.78 vs. 7.94 ± 2.63, P<0.05), 2 h-postprandial glucose(15.12 ± 11.20 vs.13.14 ± 4.72, P<0.05), e GFR(114.81 ± 39.15 vs. 103.23 ± 32.18, P<0.01), mean Hb A1c(8.32 ± 1.69 vs. 7.39 ± 1.35, P<0.01)and mean GA(22.66 ± 5.92 vs. 19.83 ± 5.18, P<0.01) than non-progression group. The frequencies of subjects with DR progression increased obviously with the increment of baseline Hb A1 c, mean Hb A1 c and mean GA according to quartile stratification of the above three glucose parameters.Multivariable binary logistic regression analysis investigated that the factors affected the DR progression were the presence of DR at baseline, mean Hb A1 c, mean GA and e GFR. The optimal cut-off values of mean Hb A1 c and GA to predict DR progression were 7.27% and 21.85%, respectively.Conclusions The presence of DR at baseline, poor glycemic control, glycated albumin, and impaired renal function predicted DR progression in patients with type 2 diabetes. GA might be a pathogenic protein in the onset or development of diabetic retinopathy. |
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