Pre-eclampsia is a valuable opportunity to diagnose chronic kidney disease: a multicentre study.

Background: Pre-eclampsia (PE) and chronic kidney disease (CKD) are known to be associated. Our objective was to assess the prevalence of CKD in a large multicentre cohort of women without acknowledged CKD who experienced a PE episode.

Methods: The setting for the study was France (Le Mans, Central France) and Italy (Cagliari, Sardinia). The study participants were patients who experienced PE in 2018-19, identified from the obstetric charts. Patients with known-acknowledged CKD were excluded. Only singletons were considered. Persistent (micro)albuminuria was defined as present and confirmed at least 3 months after delivery. CKD was defined according to the Kidney Disease Outcomes Quality Initiative guidelines; urinary alterations or low eGFR confirmed at a distance of at least 3 months, or morphologic changes. Patients were divided into four groups: evidence of CKD; no evidence of CKD; unclear diagnosis-ongoing work-up; or persistent microalbuminuria. The outcome 'diagnosis of CKD' was analysed by simple and multiple logistic regressions. Temporal series (week of delivery) were analysed with Kaplan-Meier curves and Cox analysis.

Results: Two hundred and eighty-two PE pregnancies were analysed (Le Mans: 162; Cagliari: 120). The incidence of CKD diagnosis was identical (Le Mans: 19.1%; Cagliari: 19.2%); no significant difference was found in unclear-ongoing diagnosis (6.2%; 5.8%) and microalbuminuria (10.5%; 5.8%). Glomerulonephritis and diabetic nephropathy were more frequent in Cagliari (higher age and diabetes prevalence), and interstitial diseases in Le Mans. In the multivariate logistic regression, CKD diagnosis was associated with preterm delivery (adjusted P = 0.035). Gestation was 1 week shorter in patients diagnosed with CKD (Kaplan-Meier P = 0.007). In Cox analysis, CKD remained associated with shorter gestation after adjustment for age and parity.

Conclusions: The prevalence of newly diagnosed CKD is high after PE (19% versus expected 3% in women of childbearing age), supporting a systematic nephrology work-up after PE.