Glycosylated hemoglobin level in diagnosis and management of gestational diabetes mellitus

Abstract

Objective To evaluate the value of glycosylated hemoglobin (HbAlc) level in glucose monitoring,insulin therapy and neonatal birth weight prognosis in gestational diabetes mellitus (GDM) patients.Methods Data of 1074 women who were diagnosed as GDM and delivered at Peking University First Hospital between January 1,2005 and August 31,2011 were collected and retrospective analysis was conducted.The relationship of HbAlc level with plasma glucose level of oral glucose tolerance test (OGTT),insulin administration and neonatal birth weight were investigated with Pearson correlation analysis,Logistic regression analysis or receiver operating characteristic (ROC) curve.Results OGTT was done on 1074 women with (31.8± 4.0) years old during the second and third trimester and diagnosed GDM at (27.6 ± 3.4) weeks of gestational age.Among them,glucose level of fasting and 1 and 2 hours after OGTT were (5.2 ± 0.7),(10.9± 1.4) and (9.4±1.5) mmol/L.The levels of HbAlcwere (5.57±0.48)％ at the fist time of HbAlc testing at (31.8±4.3) weeks of gestational age.(1)The average value of HbAlc in 726 women determined at one month after OGTT was (5.54±0.47)％,and increased from (5.34±0.41)％ in women with one abnormal item in OGTT to (5.47±0.41)％ and (5.71±0.46)％ in women with two or three abnormal items inOGTT (t=3.025 and 6.399,all P＜0.01).(2) HbAlc level in women received insulin therapy was higher than those who did not [(5.78±0.58) ％ vs (5.42±0.37) ％,t=9.431,P＜0.01].The sensitivity and specificity were 57.8％ and 75.5％ respectively in predicting insulin requirement in women with GDM at the cut-off value of 5.67％ for HbAlc (Logistics analysis:OR＝6.847,95％CI:4.588-10.218,P＜0.01).(3) Maternal HbAlc levelat the third trimester was higher in large for gestational age(LGA) group than that in non-LGA group [(5.75±0.52)％ vs (5.54±0.42)％,t=6.845,P＜0.01].The sensitivity and specificity were 44.8％ and 73.8％ respectively in predicting LGA at the cut-off value of 5.75％ for HbAlc (Logistics analysis:OR=2.187,95％CI:2.097-3.783,P＜0.01).(4) Maternal HbAlc level at the third trimester was higher in macrosomia group than that in non-macrosomia group [(5.88±0.53)％ vs (5.57±0.45)％,t=5.990,P＜0.01].The sensitivity and specificity were 50.4％ and 79.8％ respectively in predicting macrosomia at the cut-off value of 5.85％ for HbAlc (Logistics analysis:OR=3.299,95％CI:2.237-4.865,P＜0.01).Conclusions HbAlc level at the time of GDM diagnosis could imply the severity of disease and might predict insulin requirement.While maternal HbAlc level at the third trimester may predict the occurrence of LGA and macrosomia. Key words: Diabetes, gestational; Hemoglobin A, glycosylated; Blood glucose