Risks of Postpartum Kidney Disease Following Pre-eclampsia and Gestational Hypertension.

RATIONALE &

OBJECTIVE

Pre-eclampsia and gestational hypertension affect over 1 in 8 pregnancies in the United States. Gestational hypertension differs, in part, from pre-eclampsia by not being associated with proteinuria. However, it is unclear whether these 2 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 with those with prior pre-eclampsia.

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, pre-eclampsia without severe features, or pre-eclampsia with severe features.

OUTCOME: 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, pre-eclampsia without severe features, and pre-eclampsia with severe features were 246, 407, and 648 per 100,000 delivery hospitalizations, respectively. Compared to those with gestational hypertension, pre-eclampsia without severe features was associated with an increased hazard of any kidney disease (adjusted HR, 1.55 [95% 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 with gestational hypertension, patients with pre-eclampsia with severe features had a 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 pre-eclampsia is associated with a substantial increase in the hazard of subsequent kidney disease compared with gestational hypertension in the first year postpartum. These findings may inform clinical surveillance strategies after the occurrence of hypertensive disorders of pregnancy, in particular, pre-eclampsia.

PLAIN-LANGUAGE SUMMARY: This retrospective cohort study included over 3.4 million deliveries complicated by a new-onset hypertensive disorder of pregnancy, either gestational hypertension, pre-eclampsia without, or pre-eclampsia with severe features. These patients were followed for 1 year postpartum, over which time 1.3% were readmitted for kidney disease complications. Compared with gestational hypertension, pre-eclampsia without and with severe features was associated with a 1.6-fold and 2.4-fold increased rate of kidney disease, respectively. These findings may inform clinical follow-up strategies after the occurrence of hypertensive disorders of pregnancy, in particular, pre-eclampsia.