孕初检行口服葡萄糖耐量试验预测妊娠期糖尿病的前瞻性分析

Prospective analysis of oral glucose tolerance test in early pregnancy to predict gestational diabetes mellitus

目的探讨初检孕妇口服葡萄糖耐量试验(OGTT)的血糖对孕中期妊娠期糖尿病(GDM)的预测作用。方法招募2017年1月1日至2018年12月31日于上海市第六人民医院金山分院(上海朱泾地区)妇产科门诊产检孕妇840例,所有研究对象均在孕初检(8~16孕周)时行75 g OGTT,并在孕中期(24~28孕周)接受GDM筛查。将GDM分为仅以空腹血糖(FPG)诊断的GDM(F-GDM)和以OGTT 1h血糖(1hPG)、OGTT 2hPG诊断的GDM(P-GDM);分析孕初检FPG、OGTT 2hPG和GDM筛查的FPG、OGTT 1hPG、OGTT 2hPG的相关关系;以受试者工作特征(ROC)曲线用孕初检FPG预测F-GDM,以孕初检OGTT 2hPG预测P-GDM,分别找到最佳切点,再以该切点作为孕初检GDM诊断标准,用四格表分析初检GDM和中期GDM诊断特性。两组间比较采用t检验,相关性采用Spearman相关分析;相关系数采用Fisher Z变换法,比较采用U检验。结果(1)孕初检FPG和孕中期FPG、OGTT 1hPG和2hPG均相关(相关系数分别为r1=0.461、r2=0.146、r3=0.087,均P<0.05),但孕初检FPG和孕中期FPG相关性更好(r1与r2、r3比较P值均<0.05,r2与r3比较P>0.05);孕初检OGTT 2hPG和孕中期FPG、OGTT 1hPG和2hPG均相关(相关系数分别为r4=0.201、r5=0.425、r6=0.436,均P<0.05),但孕初检OGTT 2hPG和孕中期OGTT 1hPG、2hPG相关性更好(r4与r5、r6比较P值均<0.05,r5与r6比较P>0.05)。(2)孕初检FPG预测F-GDM的ROC曲线下最大面积0.781(95%CI:0.734~0.829,P<0.001),最佳切点4.95 mmol/L,敏感性67.3%,特异性74.4%;孕初检OGTT 2hPG预测P-GDM的ROC曲线下最大面积0.790(95%CI:0.742~0.839,P<0.001),最佳切点7.595 mmol/L,敏感性67.9%,特异性80.8%。(3)用孕初检FPG≥5.0 mmol/L和OGTT 2hPG≥7.6 mmol/L为切点诊断GDM,与孕中期诊断GDM比较:敏感性78.0%,特异性60.7%,阳性预测值33.2%,阴性预测值91.7%。结论建议在孕初检用OGTT筛查GDM,FPG≥5.0 mmol/L和OGTT 2hPG≥7.6 mmol/L可作为孕初检血糖异常参考值。

Objective To investigate the predictive effect of oral glucose tolerance test(OGTT)blood glucose on gestational diabetes mellitus(GDM)in the second trimester of pregnancy.Methods A total of 840 pregnant women were prospectively recruited from Jin Shan Branch of Shanghai Sixth Peoples′Hospital(Zhujing area of Shanghai)between January 1st,2017 and December 31st,2018.All subjects received 75 g OGTT test in initial antenatal examination(8-16 gestational week)and received GDM screening in the second trimester.GDM were divided into F-GDM[only diagnosed by fasting plasma glucose(FPG)]and P-GDM(diagnosed by OGTT 1hPG or 2hPG).Correlative relationship was analyzed between OGTT FPG,OGTT 2hPG in initial antenatal examination and OGTT FPG,OGTT 1hPG,OGTT 2hPG for GDM screening in the second trimester.The receiver operating characteristic(ROC)curve was used to predict F-GDM with OGTT FPG and P-GDM with OGTT 2hPG in initial antenatal examination,the optimal cut-off points were found respectively.Then the cut-off points were used as the diagnostic criteria of GDM in the first trimester of pregnancy.Diagnostic characteristics of GDM in initial antenatal examination and GDM in the middle stage were analyzed by four-fold table.The t test was used for comparison between the two groups,Spearman correlation analysis was used for correlation,Fisher Z transformation method was used for correlation coefficient,and u test was used for comparison.Results(1)FPG in initial antenatal examination was correlated with FPG,OGTT 1hPG or OGTT 2hPG in the second trimester(r1,r2,r3 was 0.461,0.146,0.087,respectively,all P<0.05).However,the correlation between FPG in the first trimester of pregnancy and FPG in the second trimester of pregnancy was better(r1 vs r2,r1 vs r3,both P<0.05;r2 vs r3,P>0.05).OGTT 2hPG in initial antenatal examination was correlative with FPG,OGTT 1hPG or OGTT 2hPG in the second trimester(r4,r5,r6 was 0.201,0.425,0.436,respectively,all P<0.05).However,the correlation between OGTT 2hPG in initial antenatal examination and OGTT 1hPG or OGTT 2hPG in the second trimester of pregnancy was better(r4 vs r5,r4 vs r6,both P<0.05;r5 vs r6,P>0.05).(2)The maximum area under the ROC curve of F-GDM predicted by FPG in initial antenatal examination was 0.781(95%CI:0.734-0.829,P<0.001),and the optimal cut-off of FPG was 4.95 mmol/L,the sensitivity was 67.3%,and the specificity was 74.4%.The maximum area under the ROC curve of P-GDM predicted by OGTT 2hPG in initial antenatal examination was 0.790(95%CI:0.742-0.839,P<0.001),the optimal cut-off of OGTT 2hPG was 7.595 mmol/L,the sensitivity was 67.9%,and the specificity was 80.8%.(3)Compared with GDM in the second trimester,GDM in initial antenatal examination diagnosed with these two cut-off values,the sensitivity was 78.0%,and the specificity was 60.7%,the positive predictive value was 33.2%,and the negative predictive value was 91.7%.Conclusions OGTT may be used to screen GDM in initial antenatal examination,FPG≥5.0 mmol/L and OGTT 2hPG≥7.6 mmol/L may be used as a reference value for abnormal blood glucose at the beginning of pregnancy.