For a study, researchers sought to examine the relationship between community-level social vulnerability and establishing glycemic control (defined as Hb A1c less than 6.0% or less than 6.5%) in people with pregestational diabetes. From 2012 to 2016, they conducted a retrospective cohort of persons with pregestational diabetes and singleton gestations at a tertiary care hospital. Addresses were geocoded using ArcGIS and then connected at the census tract level to the CDC’s 2018 SVI (Social Vulnerability Index), which integrates 15 Census factors to provide a composite score and four scores across thematic categories (socioeconomic status, household composition, and disability, minority status and language, and housing type and transportation). Scores vary from 0 to 1, with higher values indicating more social vulnerability at the community level. In the second or third trimesters, the primary result was Hb A1c less than 6.0%, and the secondary outcome was Hb A1c less than 6.5%. The connection between SVI score as a continuous measure and goal Hb A1c was evaluated using multivariable Poisson regression with robust error variance.

At a mean gestational age of 29.5 weeks, 41.4% (173/418) of pregnant women with type 1 diabetes reached Hb A1c less than 6.0%, and 56.7% (237/418) achieved Hb A1c less than 6.5% (SD 5.78). Pregnant women with a higher SVI score were less likely than those with a lower SVI score to have Hb A1c less than 6.0%. Each 0.1-unit increase in SVI scores reduced the likelihood of reaching Hb A1c by less than 6.0% by approximately 50% (adjusted risk ratio [aRR] 0.53; 95% CI 0.36–0.77) and by more than 30% for Hb A1c less than 6.5% (adjusted odds ratio 0.67; 95% CI 0.51–0.88). In terms of individual SVI domains, those with greater socioeconomic level (aRR 0.50; 95% CI 0.35–0.71) and household composition & disability (aRR 0.55; 95% CI 0.38–0.79) were less likely to have Hb A1c less than 6.0%. Pregnant women with pregestational diabetes who lived in a socially vulnerable location were less likely to attain glycemic control, as judged by HgbA1c values.