Black-White Disparities in Maternal In-Hospital Mortality According to Teaching and Black-Serving Hospital Status

Abstract [from journal]

Background: Maternal mortality is higher among Black compared to White people in the United States. Whether Black-White disparities in maternal in-hospital mortality during the delivery hospitalization vary across hospital types (Black-serving vs. non-Black-serving and teaching vs. non-teaching) and whether overall maternal mortality differs across hospital types is not known.

Objectives: 1) Determine whether risk-adjusted Black-White disparities in maternal mortality during the delivery hospitalization vary by hospital types - this is analysis of disparities in mortality within hospital types. 2) Compare risk-adjusted in-hospital maternal mortality among Black-serving and non-Black-serving teaching and non-teaching hospitals regardless of race - this is an analysis of overall mortality across hospital types.

Study design: We performed a population-based, retrospective cohort study of 5,679,044 deliveries among Black (14.2%) and White (85.8%) patients in three states (CA, MO, PA) from 1995-2009. A hospital discharge disposition of "death" defined maternal in-hospital mortality. Black-serving hospitals had at least 7% Black obstetric patients (top quartile). We performed risk adjustment by calculating expected death rates using predictions from logistic regression models incorporating sociodemographics, rurality, comorbidities, multiple gestations, gestational age at delivery, year, state, and mode of delivery. We calculated risk-adjusted risk ratios of mortality by comparing observed:expected ratios among Black and White patients within hospital types and then examined mortality across hospital types, regardless of patient race. We quantified the proportion of Black-White disparities in mortality attributable to delivering in Black-serving hospitals using causal mediation analysis.

Results: There were 330 maternal deaths among 5,679,044 patients (5.8 per 100,000). Black patients died more often (11.5 per 100,000) than White patients (4.8 per 100,000) (RR 2.38, 95% CI: 1.89-2.98). Examination of Black-White disparities revealed that after risk adjustment, Black patients had significantly greater risk of death (adjusted RR 1.44, 95% CI 1.17-1.79) and that the disparity was similar within each of the hospital types. Comparison of mortality, regardless of race, across hospital types, revealed that among teaching hospitals, mortality was similar in Black-serving and non-Black-serving hospitals. However, among non-teaching hospitals, mortality was significantly higher in Black-serving versus non-Black-serving hospitals (adjusted RR 1.47, 95% CI: 1.15-1.87). Notably, 53% of Black patients delivered in non-teaching, Black-serving hospitals, compared with just 19% of White patients. Among non-teaching hospitals, 47% of Black-White disparities in maternal in-hospital mortality attributable to delivering at Black-serving hospitals.

Conclusion: Maternal in-hospital mortality during the delivery hospitalization among Black patients is more than double that of White patients. Our data suggest this disparity is due to both excess mortality among Black patients within each hospital type, in addition to excess mortality in non-teaching, Black-serving hospitals where most Black patients deliver. Addressing downstream effects of racism to achieve equity in maternal in-hospital mortality will require transparent reporting of quality metrics by race to reduce differential care and outcomes within hospital types, improvements in care delivery at Black-serving hospitals, overcoming barriers to accessing high-quality care among Black patients, and eventually desegregation of healthcare.