Identifying the risk profile of anemia subtypes and hemodynamic obstetric complications in relation to peripartum cardiomyopathy

Background: Peripartum cardiomyopathy (PPCM) is a leading cause of maternal mortality worldwide, with worse outcomes associated with African Ancestry and delayed presentation. However, the mechanisms underlying PPCM are incompletely understood. Objective: Use a large, nationwide cohort to explore associations between PPCM and underexplored perinatal risk factors and complications of childbirth. Methods: Public hospital discharge data were obtained from eleven U.S. states between 2003-2019. Delivery hospitalizations, patient characteristics and obstetric complications were identified using ICD-9 and -10 CM codes. Only cases with unique patient identifiers enabling readmission analysis were included. The primary outcome was incident PPCM coded between 30 days antepartum and 150 days postpartum. Results: Of 7,424,916 delivering patients, 5,488 patients were diagnosed with PPCM. Patients with PPCM had higher rates of anemia, anemia of chronic disease (ACD), iron deficiency anemia (IDA), sickle cell disease (SCD), sickle cell trait (SCT), red blood cell (RBC) transfusion, and postpartum hemorrhage (PPH) (p<0.001 for all). Transfusion was associated with increased risk of postpartum PPCM both with PPH (OR 2.16) and without PPH (OR 1.92). In multivariable analysis antepartum diagnosis was more common in the setting of anemia (OR 2.5, p<0.001), ACD (OR 16.31 p<0.006), SCD (9.11, p=0.002) and SCT (OR 2.96 p=0.021), while IDA was associated with peripartum and postpartum PPCM (OR 2.04 p<0.001). Conclusion: Anemia subtypes, RBC transfusion, and PPH were associated with an increased risk for PPCM. The magnitude of risk varied by race and timing of presentation. Further study of peripartum interventions directed at these risk factors is warranted.