Effects Of Oral Glucose Tolerance Test And Steamed Bread Meal Test On Serum 1,5-Anhydroglucitol Levels And Agreement Of Non-Fasting Measurement

Objective:This study was conducted to explore acute changes in 1,5-AG levels after an oral glucose tolerance test（OGTT）or a steamed bread meal test（SBMT）and evaluate concordance between fasting and non-fasting levels of 1,5-AG.Simultaneous agreement of 1,5 AG with glycated hemoglobin(HbA_1c)and that with glycated albumin（GA）were further comparedMethods:The study population included participants without a prior history of diabetes（DM）who underwent an OGTT in outpatient department and Shanghai community resident.All of the participants underwent a 75 g OGTT or 100 g SBMT.Fasting and postload levels of plasma glucose and 1,5-AG were measured.Statistical analysis methods included intra-class correlation coefficient,rate of agreement analysis,mountain plot,Passing-Bablok regression,and Bland-Altman difference plots.Results:（1）In total of 681 subjects who underwent an OGTT,serum 1,5-AG levels were slightly elevated after a glucose load.Regression analysis showed that body weight was negatively associated with the range of variation in the postload 1,5-AG level（Δ1,5-AG）.There is a strong and positive association between baseline 1,5-AG andΔ1,5-AG,but not betweenΔ1,5-AG and insulin levels.The ratio of theΔ1,5-AG to the baseline 1,5-AG was higher in participants with DM（7.3%[3.4–11.5%]）than in those without DM（6.2%[3.6–9.2%]）.Agreement analyses showed good agreement of 1,5-AG levels after OGTT compared with baseline levels.（2）Among 104 Shanghai community participants,the levels of 1,5-AG slightly increased from 30 to 120 min after SBMT.Consistency analyses of 1,5-AG after SBMT showed good stability.In the same circumstances,however,stability of HbA_1cc and GA were better than that of 1,5-AG,of which HbA_1cc is the best.Conclusions:The present study demonstrated that,unlike the decrease with long-term hyperglycemia,serum 1,5-AG levels were slightly elevated by 6–7%after a glucose load.Agreement analysis provided a basis for the application of measuring 1,5-AG in non-fasting blood sample to clinical practice.Both HbA_1cc and GA stabilities were superior to that of 1,5-AG after SBMT.