Severe Maternal Morbidity in California Hospitals: Performance Based on a Validated Multivariable Prediction Model

Severe maternal morbidity (SMM) is under development as a quality indicator for maternal health care. The aim of this study is to evaluate California hospital performance based on a standardized SMM measure.

California maternal hospital delivery discharge data from 2016 to 2017 were used to develop logistic regression models for SMM, adjusted for clinical risk factors at admission. Data from 2018 were used to test the models and evaluate hospital performance. SMM was defined per the Centers for Disease Control and Prevention, including (excluding) blood transfusion. Independent models were developed for each hospital type: community, teaching, integrated delivery system (IDS), and IDS teaching. Within each type, model-based expected SMM values and observed-to-expected (O/E) ratios were calculated for each hospital. For each hospital type, hospitals were ranked by O/E ratio, and over- and underperforming hospitals were identified using 95% confidence intervals.

Rates of SMM including (excluding) transfusion by hospital type were 1.7% (0.9%) for community, 2.7% (1.5%) for teaching, 2.3% (1.2%) for IDS, and 3.0% (1.6%) for IDS teaching hospitals. In higher-volume community hospitals (≥ 500 births/year), the proportion of underperformers including (excluding) transfusion was 20.7% (11.0%). Summing over all hospital types, 25.3% (14.9%) of hospitals were identified as underperformers in that they experienced significantly more SMM events than expected including (excluding) transfusion.

California hospital discharge data demonstrated significant hospital variation in standardized childbirth SMM. These data suggest that a standardized SMM measure may help guide and monitor statewide quality improvement efforts.