Postpartum cardiac readmissions among women without a cardiac diagnosis at delivery.

Objective: To determine risk for cardiac readmissions among women without cardiac diagnoses present at delivery up to 9 months after delivery hospitalization discharge.

Methods: Delivery hospitalizations without cardiac diagnoses were identified from the 2010-2014 Nationwide Readmissions Database and linked with subsequent cardiac hospitalizations over the following 9 months. The temporality of new-onset cardiac hospitalizations was calculated for each 30-day interval from delivery discharge up to 9 months postpartum. Multivariable log-linear regression models were fit to identify risk factors for cardiac readmissions adjusting for patient, medical, and obstetrical factors with adjusted risk ratios as measures of effect (aRR).

Results: Among 4.4 million delivery hospitalizations without a cardiac diagnosis, readmission for a cardiac condition within 9 months occurred in 26.8 per 10,000 women. Almost half of readmissions (45.9%) occurred within the first 30 days after delivery discharge with subsequent hospitalizations broadly distributed over the remaining 8 months. Factors such as hypertensive diseases of pregnancy (aRR 2.19, 95% CI 2.09, 2.30), severe maternal morbidity at delivery (aRR 2.06, 95% CI 1.79, 2.37), chronic hypertension (aRR 2.52, 95% CI 2.31, 2.74), lupus (aRR 4.62, 95% CI 3.82, 5.60), and venous thromboembolism during delivery (aRR 3.72, 95% CI 2.75, 5.02) were all associated with increased risk for 9-month postpartum cardiac admissions as were Medicaid (aRR 1.57, 95% CI 1.51, 1.64) and Medicare insurance (aRR 3.06, 95% CI 2.70, 3.46) compared to commercial insurance and maternal ages 35-39 and 40-54 years (aRR 1.24, 95% CI 1.17, 1.32, aRR 1.74, 95% CI 1.60, 1.90, respectively) compared to maternal age 25-29 years.

Conclusions: Among women without a cardiac diagnosis at delivery, multiple medical factors and obstetrical complications are associated with development of new cardiac disease requiring readmission in the postpartum period. Given that pregnancy complications and comorbidities may be associated with intermediate-term health outcomes, these findings support the importance of continued health care access after six weeks postpartum.