Pre-eclampsia a risk factor for postpartum acute kidney injury

Women with pre-eclampsia are at risk of developing acute kidney injury at 90 days or beyond after giving birth, according to a study.

Researchers looked at the medical records of pregnant women aged 14–50 years who delivered at ≥20-weeks gestation in Ontario, Canada. AKI with receipt of dialysis (AKI-D) ≥90 days after delivery was the primary study outcome, while AKI based on a hospitalization with a diagnostic code for AKI ≥90 days after delivery was the secondary outcome.

The total study population comprised 1,142,656 women and 1,826,235 deliveries. Of these, 1.7 percent were associated with gestational hypertension and 4.4 percent with pre-eclampsia.

There were 322 episodes of AKI-D and 1,598 episodes of AKI based on diagnostic codes documented over a mean follow-up of 6.7 years. The corresponding incidence rates were 0.41 and 2.04 per 10,000 person-years.

Multivariable time-dependent Cox proportional and cause-specific hazards models showed that neither pre-eclampsia nor gestational hypertension contributed to an increased risk of AKI-D. However, pre-eclampsia was associated with a 22-percent higher risk of AKI based on diagnostic codes (hazard ratio, 1.22, 95 percent confidence interval, 1.03–1.45) but not gestational hypertension.

The present data highlight the potential importance of evaluating pregnancy history as part of a comprehensive risk profile for acute kidney disease. The researchers also stressed that kidney function monitoring might be beneficial to women with a history of hypertensive disorders of pregnancy (HDP).

The study was limited by its retrospective design and possible unmeasured confounding. Also, there might have been undetected cases of hypertensive disorders of pregnancy and AKI.