Introduction: Gestational diabetes mellitus (GDM) affects up to 14% of pregnancies in the U.S. and is associated with a sevenfold increased lifetime risk for type 2 diabetes (T2D). Clinical guidelines recommend postpartum glucose screening 4-12 weeks after a GDM pregnancy, and re-screening every 1-3 years thereafter. However, an inadequate proportion of persons with GDM actually receive these screenings. Racial/ethnic differences in risk of developing T2D following GDM may partially be driven by differential receipt of screening services. The aim of this study was to examine racial/ethnic differences in subsequent development of T2D, receipt of screening services, and glycated hemoglobin (HbA1c) in a nationally representative sample of women with a GDM history.
Methods: We analyzed data from the National Health and Nutrition Examination Survey (NHANES, 2007-2014). Race/ethnicity, GDM and diabetes diagnosis, and receipt of diabetes screening tests were determined by self-report; HbA1c was measured using standard laboratory procedures. Associations of race/ethnicity with outcomes of interest were evaluated using linear, logistic, and Cox regression, with adjustment for demographic, clinical, and healthcare access factors.
Results: Among 629 women with a history of GDM in NHANES, non-Hispanic Black women had 98% higher risk (95% CI (1.28, 3.08), p=0.003), and Hispanics about double the risk (HR = 2.04, 95% CI (1.25, 3.32), p=0.005) of developing T2D following GDM compared to non-Hispanic Whites. In fully adjusted models, this was attenuated slightly, although still statistically significantly greater risk for both non-Hispanic Black (p=0.05) and Hispanic (p=0.03) women. Both non-Hispanic Black and Hispanic women were less likely to report being screened for diabetes in the past 3 years. In adjusted linear regression models, among women who remained diabetes-free, non-Hispanic Blacks had 0.40-% point higher HbA1c (p=0.02), and Hispanics had 0.26-% point higher HbA1c (p<0.001) compared to non-Hispanic Whites. Additionally, the odds of prediabetes were 4.9-fold higher for non-Hispanic Blacks (p<0.001), and 2.4-fold greater for Hispanics (p=0.03) as compared to non-Hispanic Whites. Odds of undiagnosed diabetes (HbA1c>6.5%) were significantly higher in non-Hispanic Blacks (OR=3.3, p=0.05) and marginally greater in Hispanics (OR=3.5, p=0.07) compared to non-Hispanic Whites.
Conclusions: Differential receipt of follow-up services by minority women may exacerbate observed disparities in the burden of T2D. In this study, racial/ethnic disparities were apparent with regards to T2D diagnosis, receipt of diabetes screening tests, and HbA1c. Additional investigation to identify underlying factors contributing to this observed disparity will be particularly important to inform recommendations to improve delivery of quality care equitably across population subgroups.