Association between hospital case volume and maternal adverse events in patients with placental abruption: An analysis using a Japanese national inpatient database.

Abstract

To clarify the relationship between the prognosis of patients with placental abruption (PA) and the healthcare delivery system using data from a large national inpatient database in Japan. Using the Diagnosis Procedure Combination database, we conducted a retrospective cohort study with the data of patients in almost 1000 hospitals with the primary diagnosis of PA who were hospitalized from April 2014 to March 2021. We divided the hospitals into four groups based on the number of deliveries per month. We performed multilevel logistic regression analysis to analyze the relationship between hospital case volume and maternal end-organ injury (MEOI). Altogether, 8222 patients were included for analysis; among whom, 3575 (44%) were transferred by ambulance. MEOI was noted in 977 patients (12%) with no obvious difference by hospital case volume. Ambulance transfer, age, gestational weeks at admission, delivery on the first day of hospitalization, and history of eclampsia were significantly associated with a higher incidence of MEOI, but the hospital case volume was not. Using a Japanese administrative database, our study shows that hospital case volume was not significantly associated with the severity of maternal illness among patients with PA.