A Novel Nomogram for Predicting Gestational Diabetes Mellitus During Early Pregnancy

Abstract

Objective: Gestational diabetes mellitus (GDM) is a serious threat to maternal and child health. However, there isn't a standard predictive model for the disorder in early pregnancy. This study is to investigate the association of blood indexes with GDM and establishes a practical predictive model in early pregnancy for GDM.

Methods: This is a prospective cohort study enrolling 413 pregnant women in the department of Obstetrics and Gynecology in Shanghai General Hospital from July 2020 to April 2021.A total of 116pregnantwomen were diagnosed with GDM during the follow-up. Blood samples were collected at early trimester (gestational weeks 12-16) and second trimester(gestational weeks 24-26 weeks). A predictive nomogram was established based on results of the multivariate logistic model and 5-fold cross validation. We evaluate the nomogram by the area under the receiver operating characteristic curve (AUC), calibration curves and decision curve analysis (DCAs).

Results: Significant differences were observed between the GDM and normal controls among age, pre-pregnancy BMI, whether the pregnant women with complications, the percentage of B lymphocytes, fasting plasma glucose (FPG), HbA1c, triglyceride and the level of progesterone in early trimester. Risk factors used in nomogram included age, pre-pregnancy BMI, FPG, HbA1c, the level of IgA, the level of triglyceride, the percentage of B lymphocytes, the level of progesterone and TPOAb in early pregnancy. The AUC value was 0.772, 95%CI (0.602,0.942). The calibration curves for the probability of GDM demonstrated acceptable agreement between the predicted outcomes by the nomogram and the observed values. DCA curves showed good positive net benefits in the predictive model.

Conclusions: A novel predictive nomogram was developed for GDM in our study, which could do help to patient counseling and management during early pregnancy in clinical practice.

Keywords: B lymphocytes; IgA; gestational diabetes mellitus; nomogram; risk factors.

Figure 1

A novel nomogram predicting for the risk of GDM. Ten indicators in early pregnancy including age, pre-pregnancy BMI, parity, FPG, HbA1c, the level of IgA, the percentage of B lymphocytes, the level of triglyceride, the level of progesterone in early pregnancy and TPOAb were enrolled in the nomogram prediction model. The difference of the relative proportion of patients in each subgroup was represented by the area of rectangles. Patient 1 from our study is listed as an example (expressed in red). Her total score is 373 which indicating that her probability of GDM was 2.83%. GDM gestational diabetes mellitus, BMI body mass index, FPG fasting plasma glucose, CD19 the percentage of B lymphocytes, TG triglyceride. *P value between 0.01 and 0.05; **P value between 0.0009 and 0.009; ***P value < 0.0009.

Figure 2

The ROC curve and the AUC value to evaluate the discrimination ability of the nomogram. ROC receiver operating characteristic, AUC area under the receiver operating characteristic curve.

Figure 3

Calibration curves for the nomogram. The y-axis indicates the observed cumulative incidence for GDM, and the x-axis is the predicted probability of GDM based on the predictive model. The line adjacent to the ideal line represents the predictive accuracy.

Figure 4

Decision curve analysis plot of the nomogram. Blue line represent the clinical net benefits according to the threshold probabilities; horizontal line assume no cases will experience GDM; grey line assume all cases will experience GDM. GDM, gestational diabetes mellitus.