Neighborhood-level Racial/Ethnic and Socioeconomic Inequality and Severe Maternal Morbidity in the State of California: Employing the Index of Concentration at the Extremes

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Society for Pediatric and Perinatal Epidemiologic Research (SPER) 2021 Virtual Conference

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Structural racism has emerged as a root cause of racial/ethnic disparities in severe maternal morbidity (SMM), however, empirical investigations remain limited. We examined associations between the Index of Concentration at the Extremes (ICE), which quantifies area-level racial and economic inequality, and SMM to address this important gap in knowledge. We leveraged linked vital statistics and hospital discharge records from the Office of Statewide Health Planning and Development in California (OSHPD) from 1997 to 2012 to identify occurrences of SMM (as defined by the 21 Centers for Disease Control indicators). Three ICE measurements (ICE-race/ethnicity; ICEincome; ICE-race/ethnicity & income) were used to capture the individual and joint influence of racial and economic spatial polarization, based on residential census tract (n= 8057 tracts; average= 897 participants within tracts) at time of giving birth (categorized into quartiles; Q1=most inequality, Q4=least inequality). Mixed effects logistic regression models (i.e. participants nested within neighborhoods) were used to compare estimates before and after adjustment for sociodemographic factors (age, education, insurance, race/ethnicity), pregnancy-related behaviors (parity, singleton/multiple birth), and a comorbidities index. Odds ratios (ORs) with 95% confidence intervals (CIs) were reported as approximations of relative risk, given that SMM is a rare outcome. Of the 8,147,839 participants who gave birth, 1.0% experienced SMM (1.6% Black; 1.0% Hispanic; 1.0% Asian/Pacific Islander; 0.8% White; 1.2% American Indian/Alaska Native or “Other”). In the adjusted models, greater (Q1 vs. Q4) racial/ethnic inequality (OR=1.13, 95% C.I. 1.11-1.16), economic inequality (OR=1.04, 95% C.I. 1.02-1.07), and combined racial and economic inequality (OR=1.12, 95% C.I. 1.09-1.15) were associated with a higher odds of SMM. These results provide support for the harmful effects of structural racism on SMM.


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