Statistical analysis.
Participants’ baseline characteristics were summarised using means, medians, standard deviations, and interquartile ranges for continuous variables where applicable. Categorical data were summarized using numbers and proportions. We used Pearson’s chi-square and Fisher’s exact tests to assess the associations between GDM and maternal and neonatal outcomes, and present crude odds ratios (ORs).
Participants with DIP were excluded from the multivariate analysis. Univariable and multivariable logistic regression was used to investigate the effect of GDM, as a categorical variable, and OGTT blood glucose concentrations as continuous variables, for each of the primary and secondary outcomes. These were adjusted for potential confounders i.e. study site, mid-gestational BMI, maternal height, maternal age, parity, mean arterial pressure, HIV status, and previous macrosomia. These final adjust models are presented as odds ratios and their 95% confidence interval, as per the HAPO Study.3
For continuous variable analysis, odds ratios were calculated for every 1-SD increase in the fasting, 1-hour and 2-hour plasma glucose concentrations, as per the HAPO study.3 All analyses were conducted in STATA 15.1 (College Station, Texas).