Neighborhood disadvantage and the racial disparity in postpartum hypertension

Postpartum hypertension is the leading cause of postpartum readmission and has long-lasting cardiovascular effects. Black patients have higher incidence rates of hypertensive disorders after delivery and subsequent severe maternal morbidity. Neighborhood advantage, a marker of social determinants of health, has not been studied concerning postpartum hypertension. Moreover, the interplay between race and neighborhood advantage and their effect on postpartum hypertension have not been previously explored.

This study aimed to evaluate the association between neighborhood-level social determinants of health and postpartum hypertension and explore whether these factors explain previously documented racial disparities.

This study included a retrospective cohort of people enrolled in a remote monitoring program of postpartum hypertension at the time of delivery within 1 health network from March 2019 to September 2021. Patients were eligible for enrollment after a diagnosis of hypertensive disorder during pregnancy or delivery. We further limited the cohort to self-reported Black and White patients with blood pressures recorded at 3 weeks and 6 weeks postpartum. The neighborhood advantage for each person at the time of delivery was classified using the area deprivation index, an accepted surrogate of social determinants of health and our primary exposure. The secondary exposure was self-reported race. Study outcomes of interest were hypertensive status (stage 1 hypertension: ≥130 to 139/80 to 89 mm Hg; stage 2 hypertension: ≥140/90 mm Hg) at 3 and 6 weeks after delivery. In addition, hypertensive status by neighborhood area deprivation index using logistic regression was molded. In secondary analyses, a case-control cohort matched on the area deprivation index was created, and conditional logistic regression was used to evaluate race. Finally, mixed-effects models modeling hypertension by race and clustering within the area deprivation index were used.

Of 4193 people enrolled, 2722 were Black or White and had blood pressure data recorded at 3 weeks after delivery, and 1126 had blood pressure data recorded at 6 weeks after delivery. After accounting for prenatal body mass index, smoking status, type of hypertension, and antihypertensives prescribed at discharge, persons living in the most disadvantaged neighborhoods were twice as likely (adjusted odds ratio, 2.03; 95% confidence interval, 1.53-2.69) to develop stage 2 hypertension at 21 days after delivery and 1.67 times more likely (95% confidence interval, 1.06-2.64) to develop stage 2 hypertension at 6 weeks after delivery than persons living in the most advantaged neighborhoods. Both associations were attenuated after adjusting for race. When people with stage 2 hypertension were matched on area deprivation index with normotensive counterparts, Black patients were still 3 to 4 times more likely to develop stage 2 hypertension at 3 (adjusted odds ratio, 3.00; 95% confidence interval, 1.95-4.63) and 6 (adjusted odds ratio, 4.61; 95% confidence interval, 2.05-10.36) weeks after delivery. This association remained after clustering within a neighborhood at 3 (adjusted odds ratio, 3.12; 95% confidence interval, 2.41-4.06) and 6 (adjusted odds ratio, 2.99; 95% confidence interval, 1.96-4.54) weeks after delivery. There was no significant difference in stage 1 hypertension.

Neighborhood advantage was associated with the development of persistent hypertension at 3 and 6 weeks after delivery. This association did not explain the racial disparity in sustained high blood pressure.