Supplementary Material for: Preeclampsia and the Ten-Year Risk of Incident Chronic Kidney Disease

Background: Although preeclampsia (PE), as an endothelial disorder can lead to renal dysfunction during pregnancy, results of studies focusing on the potential long-term potential effects of PE on renal function are insufficient and those available are controversial. This study investigated the incidence rate and risk of chronic kidney disease (CKD) among women with prior history of PE compared with healthy controls in a long-term population-based study. Methods: This was a prospective population-based cohort study. Subjects were 1,851 eligible women, aged 20–50 years, with at least 1 pregnancy (177 women with prior-PE and 1,674 non-PE controls) selected from among the Tehran-Lipid and Glucose-Study-participants. A pooled-logistic-regression-model and Cox’s-proportional-hazards-models were utilized to estimate the risk of CKD in women of both PE and without PE groups, after further adjustment for confounders. Results: Median and interquartile ranges for follow-up durations of the PE and non-PE groups were 7.78 (5.19–10.40) and 7.32 (4.73–11.00) years, respectively. Total cumulative incidence rates of CKD at the median follow-up time of each group were 35/100,000 (95% CI 25/100,000–50/100,000) and 36/100,000 (95% CI 32/100,000–39/100,000) in PE and non-PE women, respectively (p value = 0.90). Based on pooled-logistic-regression-analysis, OR of CKD progression (adjusted for age, body mass index [BMI], systolic blood pressure [SBP], and diastolic blood pressure [DBP]) for the PE group did not differ, compared to their non-PE counterparts (OR 1.04; p value = 0.80; 95% CI 0.77–1.40). Compared to non-PE women, women with prior PE did not have higher hazard ratios (HRs) of developing CKD in the unadjusted model (unadjusted HR 1.1, 95% CI 0.83–1.69, p = 0.35), results which remained unchanged after adjustment for age, BMI, baseline SBP, and DBP. Conclusion: PE was not found to be a risk factor for CKD. More studies using a prospective cohort design with long-term follow-ups are needed to investigate the relationship between preeclamsia and CKD.