Chronic Hypertension and the Risk of Readmission for Postpartum Cardiovascular Complications.

Objective: Preeclampsia is an important risk factor for cardiovascular disease (CVD, including heart disease and stroke) along the life course. However, whether exposure to chronic hypertension in pregnancy, in the absence of preeclampsia, is implicated in CVD risk during the immediate postpartum period remains poorly understood. Our objective was to estimate the risk of readmission for CVD complications within the calendar year after delivery for people with chronic hypertension.

Methods: The Healthcare Cost and Utilization Project's Nationwide Readmission Database (2010-2018) was used to conduct a retrospective cohort study of patients aged 15-54 years. International Classification of Diseases codes were used to identify patients with chronic hypertension and postpartum readmission for CVD complications within 1 year of delivery. People with CVD diagnosed during pregnancy or delivery admission, multiple births, or preeclampsia or eclampsia were excluded. Excess rates of CVD readmission among patients with and without chronic hypertension were estimated. Associations between chronic hypertension and CVD complications were determined from Cox proportional hazards regression models.

Results: Of 27,395,346 delivery hospitalizations that resulted in singleton births, 2.0% of individuals had chronic hypertension (n=544,639). The CVD hospitalization rate among patients with chronic hypertension and normotensive patients was 645 (n=3,791) per 100,000 delivery hospitalizations and 136 (n=37,664) per 100,000 delivery hospitalizations, respectively (rate difference 508, 95% CI 467-549; adjusted hazard ratio 4.11, 95% CI 3.64-4.66). The risk of CVD readmission, in relation to chronic hypertension, persisted for 1 year after delivery.

Conclusion: The heightened CVD risk as early as 1 month postpartum in relation to chronic hypertension underscores the need for close monitoring and timely care after delivery to reduce blood pressure and related complications.