Abstract:Objective To study glycated serum protein, glycated hemoglobin HbA_1C and their interactions, and to analyze their relationship with insulin resistance (IR) in pregnant women with gestational diabetes mellitus. Methods A total of 110 pregnant women with gestational diabetes mellitus who were treated in the Xinjiang 474 Hospital from February 2020 to February 2024 were selected. The pregnant women were divided into IR group (n=32) and non-IR group (n=78) according to whether they were complicated with IR. The clinical data, GSP and HbA_1C levels of the two groups were compared. Multivariate logistic regression was used to analyze the influencing factors of IR in pregnant women with gestational diabetes mellitus, and the association of GSP, HbA_1C and their interaction with IR in pregnant women with gestational diabetes mellitus was analyzed. Multiple linear regression was used to analyze the correlation between GSP, HbA_1C and homeostasis model assessment of insulin resistance (HOMA-IR). Receiver operating curve (ROC) curve was used to evaluate the GSP, HbA_1C and their interactions on IR in pregnant women with gestational diabetes mellitus. Results Significant differences in body mass index (BMI) during pregnancy, triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), GSP, HbA_1C, fasting plasma glucose (FPG), fasting insulin (FINS), and HOMA-IR were observed between the IR and non-IR groups (P＜0.05). Multinominal logistic regression analysis revealed that increased BMI during pregnancy, GSP, HbA_1C, FPG, FINS, and HOMA-IR were independent risk factors for the occurrence of IR in pregnant women with gestational diabetes mellitus (P＜0.05). The results of multiple linear regression analysis indicated that both GSP and HbA_1C were positively correlated with HOMA- IR (P＜0.05). The multiplicative interaction model showed that there was no multiplicative interaction between GSP and HbA_1C for the occurrence of IR in pregnant women with gestational diabetes mellitus ( P> 0.05). The additive interaction model demonstrated that GSP and HbA_1C had an additive interaction on the occurrence of IR in pregnant women with gestational diabetes mellitus (P＜0.05) ; the probability of IR in pregnant women with gestational diabetes mellitus who had high expression of GSP and HbA_1C was significantly higher than in those with low expression of GSP and HbA_1C (P＜0.05). The ROC curve showed that the area under the curve (AUC) for GSP was 0.831, for HbA_1C was 0.805, and for their additive interaction was 0.882 (P＜0.05). Conclusion GSP and HbA_1C have an additive interaction effect on the occurrence of IR in pregnant women with gestational diabetes mellitus, and GSP, HbA_1C and their interaction have high clinical value in predicting IR.