Severe Maternal Morbidity, Race, and Rurality: Trends Using the National Inpatient Sample, 2012-2017

Background: Severe maternal morbidity is related to maternal mortality and an important measure of maternal health outcomes. Our objective was to evaluate differences in rates of severe maternal morbidity and mortality (SMM M) by rurality and race, and examine these trends over time. Materials and Methods: It involves the retrospective cohort study of delivery hospitalizations from January 1, 2012 to December 31, 2017 from the National Inpatient Sample. We identified delivery hospitalizations using International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis and procedure codes and diagnosis-related groups. We used hierarchical regression models controlling for insurance status, income, age, comorbidities, and hospital characteristics to model odds of SMM M. Results: The eligible cohort contained 4,494,089 delivery hospitalizations. Compared with women from small cities, women in the most urban and most rural areas had higher odds of SMM M (urban adjusted odds ratio [aOR] 1.09, 95% confidence interval [1.04-1.14]; noncore rural aOR 1.24 [1.18-1.31]). Among White women, the highest odds of SMM M were in noncore rural counties (aOR 1.20 [1.12-1.27]), while among Black women the highest odds were in urban (aOR 1.21 [1.11-1.31]) and micropolitan areas (aOR 1.36 [1.19-1.57]). Findings were similar for Hispanic, Native American, and other race women. Rates of SMM M increased from 2012 to 2017, especially among urban patients. Conclusions: Women in the most urban and most rural counties experienced higher odds of SMM M, and these relationships differed by race. These findings suggest particular areas for clinical leaders and policymakers to target to reduce geographic and racial disparities in maternal outcomes.