The Significance Of2-hour Blood Glucose After Standardized Steamed Bread Meal In Diabetes Screening

Objective To study the significance of2-hour blood glucose after standardizedsteamed bread meal (SB-2hBG) in diabetes screening. Method A retrospectivestudy about diabetes screening data of annual check-up in PLA general hospital(1996-2002) was done.100g standardized steamed bread meal test was done among thenon-diabetic subjects. Those subjects with SB-2hBG≥7.2mmol/L underwent a75g oralglucose tolerance test (OGTT) within2weeks to determine whether the diagnosis ofdiabetes mellitus (DM) could be established (WHO,1999, diagnostic criteria fordiabetes). By extracting data for7consecutive years, we analyzed the significance andthe cut-off point of SB-2hBG in the diagnosis of DM, and investigated the changes ofblood glucose curves in different glucose tolerance status after different glucose loadingtest. Result A total of3,343subjects with complete information were included in thestudy (3,101males,242females,40-94years of age). According to the results of OGTT,429(12.8%) subjects were diagnosed as DM,1405(42.1%) were diagnosed as impairedglucose regulation (IGR)(0.7%impaired fasting glucose,41.4%impaired glucosetolerance); and1509(45.1%) subjects had normal glucose tolerance (NGT). With thedeterioration of glucose tolerance status, the difference between SB-2hBG andOGTT-2hBG increased gradually, namely the NGT group1.911±1.495mmol/L, IGRgroup-0.273±1.551mmol/L, DM group-2.595±2.450mmol/L （P<0.01）, which wascharacterized by OGTT-2hBG becoming more higher than SB-2hBG gradually. Thecut-off points of FBG for the diagnosis of IGR and DM were5.3(sensitivity of46.2%,specificity of68.5%) and5.6(sensitivity of57.4%, specificity of76.4%)mmol/L,respectively. The cut-off points of SB-2hBG were8.2mmol/L for the diagnosis of IGR(sensitivity of63.8%, specificity of59.9%) and9.2mmol/L for the diagnosis of DM(sensitivity of66.4%, specificity of76.4%). If the cut-off point of SB-2hBG was set at 7.2mmol/L, the diagnostic specificity became quite low, but when the cut-off point wasset at11.1mmol/L, the sensitivity was31.5%and the specificity was95.7%for thediagnosis of DM. The coincidences of the cut-off points of FBG and SB-2hBG for thediagnosis of IGR and DM were at equal (P>0.05). When the cut-off point of SB-2hBGwas set at7.8mmol/L, the sensitivity was77.4%and the specificity was41.8%for thediagnosis of IGR, which was quite better than FBG at5.6mmol/L (P<0.01).Conclusions With the deterioration of glucose tolerance, the diference betweenSB-2hBG and OGTT-2hBG increased gradually. Compared to the diagnostic criteria ofOGTT, the best cut-off points for the diagnosis of IGR and DM were5.3mmol/L and5.6mmol/L for FBG, and8.2mmol/L and9.2mmol/L for SB-2hBG, respectively. Thediagnostic significance of the cut-off point of FBG and SB-2hBG was similar, but thesensitivity for the diagnosis of impaired glucose regulation was better for SB-2hBG at7.8mmol/L than FBG at5.3and5.6mmol/L. For diabetes screening in middle andelderly person, the cut-off points of FBG at5.3mmol/L and SB-2hBG at7.8mmol/Lwere indicators for further OGTT.