Risks of Postpartum Kidney Disease Following Preeclampsia and Gestational Hypertension

Rationale & Objective Preeclampsia and gestational hypertension affect over 1 in 8 pregnancies in the US. Gestational hypertension differs, in part, from preeclampsia by not being associated with proteinuria. However, it is unclear whether these two conditions differ in their risk of subsequent kidney disease. We studied the postpartum risks of kidney disease, comparing individuals with a history of gestational hypertension to those with prior preeclampsia. Study Design Retrospective cohort study. Setting & Participants Pregnant patients aged 15 to 54 with in-hospital deliveries in the United States, 2010 to 2020, complicated by a hypertensive disorder of pregnancy and identified in the Healthcare Cost and Utilization Project's Nationwide Readmissions Database. Exposure New-onset hypertensive disease in pregnancy, classified either as gestational hypertension, preeclampsia without severe features, or preeclampsia with severe features. Outcomes Hospital readmissions within one calendar year of delivery for acute or chronic kidney disease. Analytical Approach Multivariable Cox proportional hazards regression. Results 3,425,221 deliveries were complicated by a new onset hypertensive disease of pregnancy. The readmission rate for patients with new hypertensive disease in pregnancy was 1.3% for kidney disease complications. Kidney disease hospitalization rates for gestational hypertension, preeclampsia without severe features, and preeclampsia with severe features were 246, 407, and 648 per 100,000 delivery hospitalizations, respectively. Compared to those with gestational hypertension, preeclampsia without severe features was associated with an increased hazard of any kidney disease (adjusted hazard ratio HR 1.55, 95% confidence interval CI 1.41-1.71), acute kidney injury (HR 1.49, 95% CI 1.31-1.6), and chronic kidney disease (HR 2.31, 95% CI 1.70-3.13). Compared to gestational hypertension, patients with preeclampsia with severe features had a yet higher hazard of hospitalization for any kidney disease (HR 2.44, 95% CI 2.23-2.68) and chronic kidney disease (HR 6.03, 95% CI 4.54-8.01). Limitations Potential underreporting of kidney disease diagnoses and incomplete data on confounders. Conclusions This population-based study suggests that preeclampsia is associated with a substantial increase in the hazard of subsequent kidney disease compared to gestational hypertension in the first year postpartum. These findings may inform clinical surveillance strategies following the occurrence of hypertensive disorders of pregnancy, in particular, preeclampsia.