Clinical Utility Of An Enzymatic Method For The Measurement Of Glycated Albumin In Gestation Diabetes Mellitus

Gestation diabetes mellitus(GDM)is defined as glucose intolerance that begins, or is first recognized during pregnancy.GDM represents nearly 80-90%of all pregnancies complicated by diabetes.GDM was classified as a grade A disease by the World Health Organization in 1979 and treated as an independent category.The incidence of GDM is increasing.A wide range of complications is associated with the GDM.For mother: gestation diabetes increase the he frisk of preeclampsia,cesarean delivery,and future type 2 diabetes.In tetus or neonate,the disorder is associated with higher rate of perinatal mortality macrosomia,birth trauma,hyperbilirubinemia,and neonatalhypoglycemia.Earlier studies suggest that tight glycemic control significantly reduces perinantal morbidity in case of gestation diabetes.It is recommended that treatment of GDM shoud be aimed at lowing blood glucose to normal or near-normal levels.So the assessmentof blood glucose control becomes a crucial component of gestation diabetes mullitus treatment.Mornitoring of glycemic status is considered a cornerstone of GDM care.Self-monitoring blood glucose(SMBG)is an effective tool for monitoring glycemic status and offers several advantages,including real-time,reliable blood glucose concentration,ability to reflect postprandial excursion and improved safety through detection of hypoglycemia.But SMBG can't provied a quantitative measure of mean glucose exposure over an extended period.HemoglobinA1c(HbA1c)is a stable fraction of hemoglobin resulting from linkage of glucose to erythrocyte hemoglobin.Because the average erythrocyte lifespan is 120 days,the HbA1c level is proportional to ambient blood glucose levels during the previouse 2 to 3 months.The HbA1c levels have been widely used as an index of long-term glycemic control.HbA1c measurements have been considered the gold standard of diabetes care in the non-pregnant sate.Some diabetic programs use levels of HbA1c as a glycemic goal in the management of GDM.Several confounding factors occurs in pregnancy.GDM control is being assessed over a very short time frame,it is unclear how will HbA1c which retrospectively reflects glycemic profile over the previous 2 to 3 months reflect this.Glycated albumin(GA)is aproduct of non-enzymatic glycation.Because the tumover of human seyum albumin is much more rapid(half-life of 17 days)than that of hemoglobin,so the measurement of glycated albumin provides an index of glycemic control over a short period of time(2 weeks)than measurement of HbA1c. Additionally,serum GA levels are not affected by erythrocyte tumover.Furthermore, recently a new enzymatic method of determining GA was developed,and was confirmed to have sufficient accurancy and a good correlation with the conventional HPLC method.Recently,there are many reports on GA show that GA is a better glycemic indicator than HbA1c in diabetic subject on hemodialysis and usefulness of GA for evaluation of short-term changes in glycemic control.But to our knowledge there has no study about GA in GDM.The objectives of our investigation were to clarify the change of GA in normal pregnancy and GDM and to explore its role in the GDM.Material and Methods:Pregnant women attending the Women's Hospital School of Medicine Zhejing University for rotine prenatal clinical care were screened for GDM.Routinely,all pregnant women undergo 50g-1hGCT between the 24th-32th weeks of gestation. those whose 50g-1h GCT values are=7.8mmol/1(positive GCT)are further scheduled for a 75g-3h OGTT.Among them,women with nephritic syndrome,hypothyroidism, hyperthyroidism and overt diabetes were excluded.236 of them were evaluated.The diagnosis of GDM was based on the criteria of NDDG.236 pregnant women were divided into 3 groups:normal group(n=201);GIGT group(n=13);GDM group (n=22).GA,HbA1c and fasting plasma glucose are measured on the same day as the GCT in all case.A total of 35 GDM and GIGT patients were put on a diet and SMBG.All GDM women were monitored for metabolic and obstetric control up until delivery.while GA and HbA1c were simultaneously measured at 2 weeks intervals for 8 weeks.Plasma glucose was tested with a glucose-oxidase method.GA was determined by an enzymatic method using a liquied chemistry system(GA assay,Asahi kasei corp, Tokyo,Japan)in a clinical autoanalyzer.HbA1c was measured by a cation exchange column chromatograph(Noyco card Reader).Data are expressed as mean±SD.Correlation coefficients were calculated by simple regression analysis,and the differences in means between the two groups were analyzed by t test and one way anova.The level of significance was 0.05.The receive operating characteristic(ROC)curve was used to analyze the performance of GA to predict GDM.All analyses were performed with spss10.0 for winder.Results:1.Two hundred thirty-six subjects underwent 50g-1hGCT universal screening, one hundred twenty-three subjects who resulted positive to the 50g-1h GCT further underwent 75g-3h OGTT.Eighty-eight subjects were negative.The positive rate of GCT was 52.1%(123/236).The false positive rate of GCT was 43.78%(88/201). According to the NDDG criteric,the incidence of GIGT was 5.5%,the incidence of GDM was 9.3%(22/236).2.The mean age,fasting glucose,HbA1C and GA are all significant higher in GDM group than the normal group(p＜0.05).The mean GA(%)of normal pregnant women was 14.08±1.13%. 3.In the normal group,positive significant correlations were found between GA with HbA1c and fasting plasma glucose(p=0.01,p＜0.001);In the GIGT group, there was no strong positive correlationsbetween GA with HbA1c and fasting glucose.GA was positive significant correlation with HbA1c in the group of GDM (P=0.01).There were no positive signification correlations between GA with fasting glucose,no signification correlations between GA with albumin concentration(p =0.0173).4.Testing the GA as a screening test,at a cutoff of 14%,the sensitivity of GDM was 77.14%,the specificity was 44.28%.5.Comparison of GA,HbA1c and the GA/HbA1c ration values at baseline and 8 weeks after the start of therapy.GA was decreased more rapidly than HbA1c in GDM.The HbA1c didn't decreased significantly at 8 weeks.From as early as 4 weeks,GA show significantly decrease than the baseline.The GA/HbA1c ration was also significantly lower at 8weeks than baseline.Conclusions1.GA as measured by Lucica GA-L enzymatic assay can be a indicater for blood glucose control in gestation diabetes millutus,and provides an index of glycemic control over a short period of time(2 weeks).The mean GA(%)of normal pregnant women was 14.08±1.13%.2.GA is a sensitive marker for detecting short-term and mild changes of glycemic control during treatment in GDM.Forthermore GA is unaffected by the lifespan of erytherocytes,it can accurately reflects the glycemic control.3.GA can't be a method to screen for GDM.