Cardiomyopathies in Pregnancy: Trends and Clinical Outcomes in Delivery Hospitalizations in the United States (2005-2020)

Background

Cardiomyopathy (CDM) in pregnancy is associated with maternal morbidity and mortality.

Objectives

To explore trends and clinical outcomes in CDM subtypes during delivery hospitalizations.

Methods

We used the National Inpatient Sample database to identify delivery hospitalizations between 2005-2020 by CDM subtypes: peripartum (PPCM), dilated (DCM), hypertrophic (HCM), and restrictive (RCM). Maternal and fetal outcomes were identified using International Classification of Diseases, 9th and 10th Revision, Clinical Modification codes. Baseline characteristics and temporal trends of CDM subtypes were analyzed. Maternal cardiovascular, pregnancy, and fetal outcomes were evaluated by CDM subtype using univariate logistic regression. The primary outcome was in-hospital mortality.

Results

During 2005-2020, 37,125 out of 61,811,842 delivery hospitalizations were complicated by CDM. Among CDM-related delivery hospitalizations, the most prevalent were DCM (46%), followed by PPCM (45.6%), HCM (4.6%), and RCM (3.9%). The rates of in-hospital mortality (1.7%), adverse cardiovascular events such as acute heart failure (17%), cardiogenic shock (3.4%), and cardiac arrest (3.1%), and adverse pregnancy outcomes such as preeclampsia (14.2%) and preterm labor (11%), were highest among PPCM (all p < 0.0001). The prevalence of PPCM (49.1% to 38.5%) decreased while the prevalence of HCM (2.7% to 8.8%) and DCM (48% to 52.2%) increased over time.

Conclusions

Over a 15-year period, PPCM had higher rates of in-hospital mortality, cardiovascular events, and adverse pregnancy outcomes compared to other CDM subtypes. While the prevalence of PPCM decreased over time, the prevalence of HCM and DCM increased. Hence, further research on cardiomyopathies during pregnancy and prospective studies on this vulnerable patient cohort are urgently needed.