Worldwide, 2% to 5% of pregnancies are complicated by preeclampsia, a systemic disorder characterized by endothelial dysfunction after 20 weeks of gestation. Women who experience preeclampsia are at increased long-term risk for hypertension, cardiac disease, and cerebrovascular disease. Few data are available regarding the association between preeclampsia and long-term risk for kidney failure.
Jennifer H. Yo, MPH, PhD, and colleagues conducted a population-based cohort study in Stockholm, Sweden, to quantify the risk for chronic kidney disease (CKD) among women who experienced preeclampsia compared with women who did not experience preeclampsia.
The researchers defined three coprimary outcomes of interest: (1) incident CKD; (2) incident albuminuria; and (3) a composite outcome of estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2 and/or albuminuria greater than 300 mg/g. Participants had all outcomes measured on two occasions at least 3 months apart.
The overall study cohort included 171,693 pregnancies (170,192 women). Of those, 6% (n=10,538) of pregnancies were complicated by preeclampsia. On average, women in the preeclampsia arm were older (30 years vs 29 years) and had higher BMI (24 vs 23 kg/m2) than women in the non-preeclampsia arm. Following inverse probability weighting, the two groups were well balanced in all baseline characteristics.
Follow-up continued for a median of 7.0 years. During the follow-up period, albuminuria greater than 300 mg/g occurred after 0.5% of pregnancies (n=775), eGFR of 60mL/min/1.73 m2 or lower occurred after 0.1% of pregnancies (n=248), and the composite outcome occurred after 0.6% of pregnancies (n=985).
Researchers observed an association between pregnancies complicated by preeclampsia and a higher incidence rate of albuminuria greater than 300 mg/g and eGFR lower than 60 mL/min/1.73 m2 after preeclampsia versus no preeclampsia: (1.53 per 1,000 person-years [95% CI, 1.27-1.84] vs 0.57 per 1,000 person-years [95% CI, 0.53-0.61] and 0.53 [95% CI, 0.37-0.71] per 1,000 person-years vs 0.18 [95% CI, 0.16-0.21] per 1,000 person-years, respectively). The weighted hazard ratios were 2.53 (95% CI, 2.04-3.13) and 2.18 (95% CI, 1.49-3.19), respectively. For the composite outcome, the weighted hazard ratio was 2.43 (95% CI, 2.01-2.95).
Limitations to the findings cited by the authors included the change over the study period in the definition of preeclampsia, the study population being limited primarily to women born in Nordic countries with access to universal healthcare, and a lack of data on kidney function at the time of pregnancy for many women included in the study.
“Our study suggests that preeclampsia is associated with earlier, detectable kidney injury using routine laboratory markers such as urine albumin and eGFR—often long before kidney failure develops,” Dr. Yo concluded. “This is important because early albuminuria is actionable, and identifying risk sooner creates a realistic opportunity to intervene with kidney-protective therapies and potentially modify long-term outcomes. These findings support considering a history of preeclampsia as an important CKD risk factor in adult practice and strengthen the case for more systematic postpartum kidney screening to identify disease earlier and enable timely intervention.”