Factors associated with postpartum readmission for hypertensive disorders of pregnancy

Abstract

Postpartum readmission has negative implications for patients and health systems. Previous studies suggest that up to 5% of women with hypertensive disorders of pregnancy experience postpartum readmission. Studies examining factors associated with postpartum readmission for hypertension have had small sample sizes and conflicting results. This study aimed to characterize the incidence of and risk factors for postpartum readmission for hypertensive disorders of pregnancy among a cohort of women with preexisting hypertensive disorders of pregnancy. This was a retrospective cohort study of pregnant women with known hypertensive disorders of pregnancy who delivered live births in a large managed care organization in 2018. The primary outcome was hospital readmission for a hypertensive diagnosis or stroke within 42 days after delivery. The primary exposure of interest was persistent postpartum hypertension, defined as a maximum systolic blood pressure of ≥140 mm Hg or maximum diastolic blood pressure of ≥90 mm Hg within 24 hours before discharge from delivery hospitalization. Continuous and categorical variables were compared using bivariate analysis. Risk factors independently associated with postpartum readmission were identified using multivariable logistic regression. Of 42,022 women who delivered in 2018, 7151 had hypertensive disorders of pregnancy-an incidence of 17%. The rate of postpartum readmission among women with hypertensive disorders of pregnancy was 4.43% (317 of 7151). The following risk factors were associated with increased odds of postpartum readmission in women with hypertensive disorders of pregnancy: systolic blood pressure of ≥140 mm Hg within 24 hours before discharge (adjusted odds ratio, 2.29; 95% confidence interval, 1.71-3.07), diastolic blood pressure of ≥90 mm Hg within 24 hours before discharge (adjusted odds ratio, 1.33; 95% confidence interval, 1.02-1.73), maternal age of ≥30 years (30-34: adjusted odds ratio, 1.57; 95% confidence interval, 1.12-2.19; 35-39: adjusted odds ratio, 2.36; 95% confidence interval, 1.70-3.28; ≥40: adjusted odds ratio, 2.95; 95% confidence interval, 1.95-4.46), receipt of magnesium sulfate (adjusted odds ratio, 1.47; 95% confidence interval, 1.11-1.94), and receipt of inpatient rapid-acting antihypertensive medication (adjusted odds ratio, 1.46; 95% confidence interval, 1.10-1.93). In addition, 1 blood pressure of ≥140/90 mm Hg within 24 hours before discharge increased the odds of readmission (adjusted odds ratio, 1.98; 95% confidence interval, 1.37-2.87). Furthermore, 2 or more elevated blood pressure values further increased the odds (adjusted odds ratio, 3.14; 95% confidence interval, 2.33-4.24). Median postpartum day of readmission was day 5 (interquartile range=3). Hospital readmission for postpartum hypertension was associated with persistent postpartum hypertension (blood pressure of ≥140/90 mm Hg), increasing maternal age, and more severe antepartum hypertension. Women with these characteristics may be targeted in future quality initiatives to mitigate readmission.