Services and payer mix of Black-serving hospitals and related severe maternal morbidity

Background: Black-serving hospitals are associated with increased maternal risk. However, prior administrative data research on maternal disparities has generally included limited hospital factors. More detailed evaluation of hospital factors related to obstetric outcomes may be important in understanding disparities. Objective: To examine detailed characteristics of Black-serving hospitals and how these characteristics are associated with risk for severe maternal morbidity (SMM). Methods: This serial cross-sectional study linked the 2010-2011 Nationwide Inpatient Sample and the 2013 American Hospital Association Annual Survey Databases. Delivery hospitalizations occurring to women 15-54 years of age were identified. The proportions of non-Hispanic Black patients within a hospital was categorized into quartiles, and hospital factors such as specialized medical, surgical and safety-net services as well as payer mix were compared across these quartiles. A series of models was performed evaluating risk for SMM with Black-serving hospital quartile as the primary exposure. Log linear regression models with a Poisson distribution (and robust variance) were performed with unadjusted and adjusted risk ratios (aRR) with 95% confidence intervals (CIs) as measures of effect. Results: Overall 965,202 deliveries from 430 hospitals met inclusion criteria and were included in the analysis. By quartile, non-Hispanic Black patients accounted for 1.3%, 5.4%, 13.4%, and 33.8% of patients. Many services were significantly less common in the lowest compared to the highest Black-serving hospital quartile including cardiac intensive care (48.9% versus 74.5%), neonatal intensive care (28.9% versus 64.9%), pediatric intensive care (20.0% versus 45.7%), pediatric cardiology (29.6% versus 44.7%), and HIV/AIDS services (36.3% versus 71.3%) (p≤0.01 for all). Indigent care clinics, crisis prevention, and enabling services (p≤0.01 for all) were more common at Black-serving hospitals as was Medicaid payer. Following adjustments for detailed hospital factors, the lowest Black serving hospital quartile carried the lowest risk for SMM. However, SMM risks were similar across the 2^nd (aRR 1.31, 95% CI 1.08, 1.59), 3^rd (aRR 1.27, 95% 1.05, 1.55), and 4^th (aRR 1.29, 95% CI 1.07, 1.55) quartiles. Conclusion: Black-serving hospitals were more likely to provide a range of specialized medical, surgical, and safety-net services and to have a higher Medicaid burden. Payer mix and unmeasured confounding may account for some of the maternal risk associated with Black-serving hospitals.