Association of chronic kidney dysfunction and preeclampsia: insights of the Nationwide Inpatient Sample

Background: Preeclampsia occurs in 3% to 5% of pregnancies and can lead to potentially fatal outcomes for parent and child. Disparities in socioeconomic status, medical access, racial or ethnic, and regional background within the United States result in a very heterogenic population.

Objective: We aimed to assess the regional differences in the severity of chronic kidney disease in pregnant patients as well as the risk of preeclampsia in a contemporary cohort within the United States.

Study design: Pregnant patients were identified within the National Inpatient Sample database between 2015 and 2019. Patients were stratified by diagnosis of end-stage kidney disease or chronic kidney disease. The primary endpoint of this study was to determine the incidence of mild preeclampsia, severe preeclampsia, and eclampsia in hospitalized pregnant patients with kidney dysfunction compared with controls. Secondary endpoints were to determine regional, racial or ethnic, and socioeconomic differences within the United States.

Results: A total of 16,343,563 pregnant patients were identified from 2015 to 2019. Presence of chronic kidney disease increased risk of mild and severe preeclampsia independent of the stage of chronic kidney disease (odds ratio >2 each). There was a markedly difference in prevalence of chronic kidney disease in regard to geographic location within the United States, with patients in the Northeast having predominantly milder stages of chronic kidney disease and patients in the South and West having more progressive kidney disease. There was a significant difference in chronic kidney disease distribution in relation to racial/ethnic background within the United States. Black and Latinx patients were at increased risk of eclampsia and death. There was no significant difference regarding chronic kidney disease and socioeconomic background. However, a larger proportion of patients with very low income had advanced stages of chronic kidney disease.

Conclusion: Our data add to the previous findings that patients with chronic kidney disease are at increased risk of developing preeclampsia even in the modern era of medical management, independent of the cause of chronic kidney disease. Racial or ethnic and geographic differences in chronic kidney disease prevalence exist. A multidisciplinary team approach to follow-up with pregnant patients with chronic kidney disease could decrease maternal and neonatal mortality.