Decomposing Racial Disparities in Severe Maternal Morbidity Within Insurance Groups

Rates of severe maternal morbidity (SMM) are related to maternal, hospital, and residential factors, but the contribution of these factors to racial disparities in SMM within Medicaid and private insured groups is largely unknown. Linked Georgia vital records/hospital discharge data for 2016-2020 are used to identify SMM during delivery or within 42 days postpartum for Medicaid and private insured. The Oaxaca-Blinder decomposition is used to describe the percentage of the Black-White SMM gap explained, based on linear probability models without and with hospital fixed-effects. While the rate of SMM is higher for Medicaid than private insured, the Black-White SMM gap is lower within Medicaid than private insured (1.15 vs. 1.40 per 100 deliveries). Including hospital fixed-effects increased the explained gap by 29.1 percentage points (from 13.8% to 42.9%) within Medicaid and by 9.4 percentage points (from 20.0% to 29.4%) within private insured. Residential factors significantly reduced the Black-White gap explained for Medicaid (-19.6%) but were insignificant (∼0%) for privately insured. According to the Oaxaca-Blinder algebraic calculation, differences in within-hospital processes by race contribute a large portion of the discriminatory Black-White SMM gap among Georgia deliveries while residential areas with greater provider access tends to reduce the gap among Medicaid insured.