One in 10,000 pregnant women suffer from acute kidney injury and are treated with dialysis: study

The estimated incidence of acute kidney injury treated with dialysis is one in 10,000 pregnancies according to researchers at the Institute for Clinical Evaluative Sciences (ICES) and Lawson Health Research Institute.

The study, published today in the Journal of the American Society of Nephrology, examines pregnancy-related acute kidney injury in a developed nation, and contains more than three times the number of cases treated with dialysis as other reports.

“Our study looked at nearly two million women in Ontario, and the incidence and outcomes of acute kidney injury treated with dialysis during pregnancy or within 12 weeks of delivery,” said author Dr. Amit Garg, director of Living Kidney Donation and a kidney specialist at the London Health Sciences Centre (LHSC), a researcher at Lawson and ICES, and a professor of medicine and epidemiology & biostatistics at Western University.

Acute kidney injury occurs when the kidneys suddenly become unable to filter waste products from the blood. When the kidneys lose their filtering ability, dangerous levels of wastes may accumulate. Acute kidney failure can be fatal and the most severe cases may require intensive treatment with dialysis. However, acute kidney failure may be reversible.

Although acute kidney injury is a rare complication of pregnancy, it may be associated with significant morbidity and mortality in young and often otherwise healthy women.

In the study, the researchers looked at all pregnancies in Ontario from 1997 to 2011 and found:

• One in 10,000 pregnancies was complicated by acute kidney injury that was treated with dialysis, either during pregnancy or the postpartum period.
• Most women who developed acute kidney injury during pregnancy had no recorded preexisting health conditions.
• Women with pre-pregnancy hypertension, diabetes, chronic kidney disease or systemic lupus erythematosus (an autoimmune disease) were at least twice as likely to develop acute kidney injury requiring dialysis during pregnancy.
• Women who had a major complication during pregnancy, such as preeclampsia, heart failure, and postpartum hemorrhage, were nearly four times more likely to develop acute kidney injury requiring dialysis during pregnancy.
• Four per cent of women whose pregnancy was complicated by acute kidney injury requiring dialysis died within 90 days of delivery.
• Of the pregnant women with acute kidney injury who survived beyond 90 days of delivery, four per cent remained dialysis dependent.
• Adverse perinatal outcomes occurred in 35 per cent of pregnancies affected by acute kidney injury, however there were no stillbirths and fewer than five neonatal deaths during the study period.

“Acute kidney injury treated with dialysis during pregnancy is rare and typically occurs in healthy women who acquire a major pregnancy-related medical condition such as preeclampsia,” said lead author Dr. Ainslie Hildebrand, a kidney specialist at the London Health Sciences Centre (LHSC). “Many affected women and their babies had good short-term outcomes and only required use of dialysis treatments for a short period of time before their kidneys recovered.”

The researchers add that a decline in pregnancy-related acute kidney injury occurred after the reduction in septic abortions in the 1960s. However, the changing risk profile of the current pregnant populations, which have seen an increase in the prevalence of advanced maternal age, preexisting diabetes and chronic kidney disease, and use of reproductive technologies, may have a unique impact on the incidence and cause of pregnancy-related acute kidney injury.                                                                                                                      

“Characteristics and outcomes of acute kidney injury treated with dialysis during pregnancy and the postpartum period,” was published in the Journal of the American Society of Nephrology.

Author block: Ainslie M. Hildebrand, Kuan Liu, Salimah Z. Shariff, Joel G. Ray, Jessica M. Sontrop, William F. Clark, Michelle A. Hladunewich, Amit X. Garg.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.

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This work was done by the new provincial ICES Kidney, Dialysis and Transplantation Research Program. Lawson Health Research Institute. As the research institute of London Health Sciences Centre and St. Joseph's Healthcare London, and working in partnership with Western University, Lawson Health Research Institute is committed to furthering scientific knowledge to advance healthcare around the world. www.lawsonresearch.com

For more information, or to arrange an interview, please contact:

• Deborah Creatura, ICES
• [email protected]
• (o) 416-480-4780 (c) 647-406-5996

• Julia Capaldi, Lawson Health Research Institute
• [email protected]
• (w) 519-685-8500 ext. 75616 or (c) 519-200-1115