Postpartum Diabetes Screening and Conversion Rates Among Women Diagnosed with Gestational Diabetes Mellitus Using Standard versus Modified Criteria During the COVID-19 Pandemic.

Aims: To examine postpartum diabetes screening and rates in women diagnosed with gestational diabetes mellitus (GDM) using standard versus modified criteria during the COVID-19 pandemic.

Methods: Individuals with GDM pregnancies between January 1, 2020, and December 31, 2021, in Alberta, Canada, were stratified by the GDM diagnosis criteria used and followed for 18-months postpartum diabetes screening. Proportions of prediabetes and diabetes were compared between the standard versus modified GDM criteria groups at 6 and 18 months. Multivariable logistic regression analysis was used to examine differences in prediabetes and diabetes rates between the two GDM criteria groups after adjusting for baseline differences.

Results: Among 10,238 individuals with GDM, 780 were diagnosed using the modified criteria and 9,458 using the standard criteria. There was no difference in the proportion of individuals who underwent postpartum screening by 6-months (27.1% versus 28.9%, p=0.29) or by 18-months (43.1% versus 45.3%, p=0.24), among modified and standard groups, respectively. Diabetes proportions were higher in women diagnosed with GDM using the modified criteria than in those diagnosed using the standard criteria (27.0% versus 4.2%, p<0.0001; adjusted odds ratio 8.18, 95% confidence interval 5.76-11.6). Proportions of prediabetes and diabetes at 18-months were 15.2% and 20.8% (p=0.014), and 29.8% and 6.1% (p<0.0001), among modified and standard groups, respectively.

Conclusion: Regardless of the GDM diagnostic method, postpartum diabetes screening among women with GDM was suboptimal during the COVID-19 pandemic. The modified criteria for GDM identified a group of women who were at higher risk for conversion to diabetes.