Background and Objectives: Pregnant women with chronic kidney disease (CKD) are at high risk of adverse maternal and fetal outcomes. Preeclampsia (PE) superimposed on CKD is estimated to occur in 21%-79% of pregnancies. Both conditions share common features such as proteinuria and hypertension, making differential diagnosis difficult. Objective: The aim of this study was to evaluate the incidence and the clinical-biological predictors of preeclampsia in pregnant women with CKD. Material and Methods: We retrospectively analyzed 34 pregnant women with pre-existing CKD admitted to our department between 2008 and 2017. Results: Among the 34 patients, 19 (55.8%) developed PE and the mean time of occurrence was 31.26 ± 2.68 weeks of gestation. The median value of 24-h proteinuria at referral was 0.87 g/day (interquartile range 0.42-1.50) and 47.1% of patients had proteinuria of ≥1 g/day. Patients with PE tended to be more hypertensive, with a more decreased renal function at referral and had significantly higher proteinuria (1.30 vs 0.63 g/day, p = 0.02). Cox multivariate analysis revealed that proteinuria ≥1 g/day at referral and pre-existing hypertension were independently associated with PE (adjusted hazard ratio = 4.10, 95% confidence interval: 1.52-11.02, p = 0.005, adjusted hazard ratio = 2.62, 95% confidence interval: 1.01-6.77, p = 0.04, respectively). The cumulative risk of PE was significantly higher in pregnant women with proteinuria ≥1 g/day at referral (log-rank, p = 0.003). Proteinuria ≥ 1 g/day at referral and pre-exiting hypertension predicted PE development with accuracies of 73.5% and 64.7%, respectively. Conclusions: Pregnant patients with pre-existing CKD are at high risk of developing preeclampsia, while proteinuria ≥ 1 g/day at referral and pre-existing hypertension were independent predictors of superimposed preeclampsia.
Keywords: chronic kidney disease; hypertension; preeclampsia; proteinuria.