Previous pre-eclampsia ups risk of later kidney disease
Women with a history of pre-eclampsia, particularly early preterm pre-eclampsia, are at an increased risk of developing several chronic renal disorders later in life, making it critical to monitor for kidney disease in the years immediately after pregnancy, according to a study.
“Early detection of chronic renal disorders would allow for early intervention to delay disease progression,” researchers said. “[I]deally, detection of the antecedents of these disorders would permit implementation of measures to prevent the onset of chronic kidney disease entirely.” [BMC Nephrol 2012;13:108; Kidney Int Rep 2016;2:142-151]
Overall, 1,072,330 women were followed for 19,994,470 person-years (mean, 18.6 years per woman). Those with a history of pre-eclampsia had a higher risk of developing chronic renal conditions than women with no previous pre-eclampsia (early preterm pre-eclampsia [delivery <34 weeks]: hazard ratio [HR], 3.93; 95 percent CI, 2.90–5.33; late preterm pre-eclampsia [delivery 34–36 weeks]: HR, 2.81; 2.13–3.71; term pre-eclampsia [delivery ≥37 weeks]: HR, 2.27; 2.02–2.55). [BMJ 2019;365:l1516]
Specifically, associations were robust for chronic kidney disease, hypertensive kidney disease and glomerular/proteinuric disease. These associations were partially attenuated after adjustment for cardiovascular disease and hypertension.
Stratifying the analyses on time since pregnancy revealed stronger associations of pre-eclampsia with chronic kidney disease and glomerular/proteinuric disease within 5 years of the latest pregnancy (HR, 6.11; 3.82–9.72 and HR, 4.77; 3.88–5.86, respectively) than ≥5 years after the latest pregnancy (HR, 2.06; 1.69–2.50 and HR, 1.50; 1.9–1.88, respectively). On the other hand, associations between pre-eclampsia and acute renal conditions were modest.
Previous studies have shown the robust association of pre-eclampsia with later cardiovascular disease, hypertension and diabetes, all of which are known predictors of chronic kidney disease and could be suspected of driving such associations. [Eur J Epidemiol 2013;28:1-19; BMJ 2017;358:j3078; Hypertension 2009;53:944-951]
“However, our results indicated that comorbid conditions, cardiovascular disease and hypertension in particular, could only partially explain the observed associations, suggesting that at least part of the link between pre-eclampsia and chronic kidney disease might arise from common predisposing factors such as increased susceptibility to vascular endothelial dysfunction,” researchers said.
The current nationwide, register-based, cohort study included all women with at least one pregnancy lasting at least 20 weeks between 1978 and 2015 in Denmark. Cox regression was used to estimate HRs comparing rates of kidney disease between women with and without a history of pre-eclampsia, stratified by gestational age at delivery.
This study was limited by lack of data on prepregnancy body mass index, potential residual confounding by other unmeasured covariates and predominantly white European women in the cohort, which could limit the generalizability of the findings to other populations with different covariate distributions.
“[M]ore research is needed to determine which women are at greatest risk of kidney disease after pre-eclampsia, what mechanisms underlie the association, and therefore what follow-up and interventions (and in what timeframe postpregnancy) would be most appropriate and effective,” researchers said.