Persistent postpartum proteinuria, renal dysfunction, and future chronic kidney disease risk in women with preeclampsia

Objectives: Previous studies demonstrated that preeclampsia (PE) with proteinuria is associated with concurrent renal injury. However, it is unclear how renal damage that occurs during pregnancy changes after delivery. This study was conducted to assess postpartum renal impairment in women with PE and to examine its possible link to the subsequent development of chronic kidney disease (CKD). Study design: We conducted a retrospective cohort study analyzing a group of women with PE and proteinuria (PE-UP (+)) (N = 30). Control data were obtained from normotensive participants at 35 weeks of gestation (N = 20) and 12 weeks postpartum (N = 15).Main Outcome Measures.Serum hyaluronan (glycocalyx injury), urinary podocalyxin (podocyte injury), urinary liver-type fatty acid-binding protein (L-FABP) and N-acetyl-β-D-glucosaminidase (NAG) (tubular injury) were measured at PE diagnosis and at 12 weeks postpartum. Results: Based on the urinary protein/creatinine ratio (UPCR) at 12 weeks postpartum, the PE-UP (+) group was stratified into the PE-UP improved group (UPCR <0.15 g/g Cr; N = 20) and PE-UP persistent group (UPCR ≥0.15 g/g Cr; N = 10). The urinary L-FABP and NAG levels in the PE-UP improved group were significantly lower than those in the PE-UP persistent group. In contrast, the levels of hyaluronan and podocalyxin remained significantly elevated in both PE subgroups compared to those in the postpartum controls. Conclusions: Postpartum women with PE and prolonged proteinuria exhibit residual tubular dysfunction. Women with PE in whom proteinuria has resolved may still have residual glomerular damage at 12 weeks postpartum.The clinical trial described in this paper was registered at the UMIN Clinical Trials Registry under registration number UMIN000058351.URL of registration: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000066708