Patients with pregnancy-related end-stage kidney disease (ESKD) may experience reduced access to nephrology care and to kidney transplant, according to a recent study published in JAMA Network Open. Further, Black patients were found to be nearly twice as likely as White patients to experience pregnancy-related ESKD.
Acute kidney injury (AKI) during pregnancy is associated with significant morbidity including a high risk of severe outcomes that include a 13-fold increased risk of maternal mortality and 9-fold increased risk of cardiovascular events, according to study authors. Significant disparities observed in pregnancy outcomes between White and Black patients extend to kidney disease, they added, with one morbidity review committee reporting 32.6 cases of AKI per 10 000 hospitalizations in Black patients compared to 10.9 for White patients.
Pregnancy-associated AKI may lead to ESKD requiring dialysis or kidney transplant and has been increasing in recent decades. “In light of the recent Supreme Court decision in Dobbs v. Jackson further restricting abortion access, rates of pregnancy-related kidney disease will likely continue to increase,” they stressed, prompting their research to examine the characteristics and clinical outcomes of patients with pregnancy-related ESKD and to investigate associations between pre-ESKD nephrology care and outcomes.
Investigators, led by Monica L Reynolds, MD, MSCR, UNC Kidney Center, Division of Nephrology and Hypertension, Department of Medicine, University of North Carolina at Chapel Hill, used data from the US Renal Data System, which records all patients with ESKD in the United States. The study population included 183 640 women aged 14 to 50 years with dialysis or preemptive kidney transplant from January 1, 2000, to November 20, 2020, with a primary cause of kidney failure reported.
Categories for nonpregnancy-related causes of kidney failure included diabetes, hypertension, glomerulonephritis, cystic kidney disease, and other or unknown causes. Investigators compared baseline characteristics of participants with pregnancy-related ESKD with those of the general population of pregnant patients, including age, race, ethnicity, body mass index, diabetes, chronic hypertension, and smoking status.
Investigators followed participants until death or November 20, 2020 (end of study), with death confirmed using linkage to the Social Security Master Death File. They defined access to kidney transplant as, “joining the deceased donor waiting list or receiving a kidney transplant from a living donor.”
Differences in access to kidney transplant and time to transplant after joining the waitlist were evaluated to compare the hazard of death between cohorts. Differences in pre-ESKD care were evaluated by examining whether participants had access to nephrology care, arteriovenous graft or fistula, or had been informed about kidney transplant before ESKD onset.
Reynolds and team identified 341 participants with a pregnancy-related primary cause of ESKD, with Black individuals overrepresented in this group compared to the general birthing population and White individuals underrepresented. Of those with pregnancy-related ESKD, 5.3% had diabetes vs 1.1% of the general birthing population. Chronic hypertension rates in the 2 groups were 68.8% and 0.7%, respectively.
A pregnancy-related primary cause of ESKD was reported in 0.19% of patients with ESKD. Nonpregnancy causes of ESKD included diabetes in 38.1%, hypertension in 19.8%, glomerulonephritis in 21.9%, cystic kidney disease in 4.6%, and other or unknown cause in 15.3%. Patients with pregnancy-related ESKD were more likely to be younger, have Medicaid only, be Hispanic, and be in school or employed.
Investigators found survival rates lowest in individuals with diabetes or hypertension as the primary cause of ESKD vs pregnancy-related causes and glomerulonephritis or cystic kidney disease. An adjusted inverse hazard ratio of 0.49 for death was reported when comparing pregnancy-related ESKD with diabetes or hypertension vs 0.96 when compared with glomerulonephritis or cystic kidney disease.
Access to kidney transplant was less likely for participants with pregnancy-related ESKD compared to patients with glomerulonephritis or cystic kidney disease (adjusted inverse subhazard ratio (aSHR) 0.51, diabetes or hypertension (aSHR 0.81) or other unknown causes (aSHR 0.82), according to study findings.
Reynolds et al also reported that patients with pregnancy-related ESKD had reduced rates of access to nephrology care before ESKD onset compared to patients with other causes of ESKD, at 33.6% vs 58.1 - 77.6%. Similar results were observed for having a graft or fistula placed before ESKD onset, at 4.4% vs 11.3% - 18%. When researchers adjusted models for demographic and clinical characteristics these differences persisted.
The investigators also reported that Black participants were at the highest risk of pregnancy related ESKD, accounting for nearly one-third of this group compared with just 16.2% of the US general birthing population.
“To our knowledge, this is the largest study of patients with a pregnancy-related primary cause of ESKD, and the first to assess outcomes as compared with those with nonpregnancy-related causes,” wrote the authors. The results strongly suggest reduced access to care among patients with pregnancy-related ESKD; investigators recommended future research within a larger population of patients with pregnancy-related AKI.