Pre-eclampsia after Kidney Transplantation: Rates and Association with Graft Survival and Function.

BACKGROUND: Transplanted women have high rates of pre-eclampsia. However, determinants of pre-eclampsia and association with graft survival and function remain uncertain. We aimed to determine rates of pre-eclampsia and its association with kidney transplant survival and function.

METHODS: Retrospective cohort study analyzing post-kidney transplantation pregnancies (≥20 weeks gestation) from the Australia and New Zealand Dialysis and Transplant Registry (2000-2021). Graft survival was assessed in 3 models accounting for repeated pregnancies and episodes of pre-eclampsia.

RESULTS: Pre-eclampsia status was captured in 357/390 pregnancies and occurred in 133 pregnancies (37%). The percentage of pregnancies reported to have pre-eclampsia rose from 27% in 2000-2004, to 48% from 2018-2021. Reported prior exposure to calcineurin inhibitors was high overall, and higher in women who had pre-eclampsia (97% vs 88%, p=0.005). Seventy-two (27%) graft failures were identified after a pregnancy, with median follow-up of 8.08 years. Although women with pre-eclampsia had higher median preconception serum creatinine concentration (1.24 ((IQR) 1.00-1.50) vs. 1.13 (0.99-1.36) mg/dL; p=0.02), in all survival models, pre-eclampsia was not associated with higher death-censored graft failure. In multivariable analysis of maternal factors (age, body mass index, primary kidney disease and transplant-pregnancy interval, preconception serum creatinine concentration, era of birth event and Tacrolimus or Cyclosporin exposure) only era and preconception serum creatinine concentration ≥1.24 mg/dL (odds ratio 2.48, 95% CI 1.19-5.18) was associated with higher pre-eclampsia risk. Both preconception eGFR <45 ml/min/1.73m 2 (adjusted HR 5.55, 95% CI 3.27-9.44, p<0.001) and preconception serum creatinine concentration ≥1.24 mg/dL (adjusted HR 3.06, 95% CI 1.77-5.27, p<0.001) were associated with a higher risk of graft failure even after adjusting for maternal characteristics.

CONCLUSIONS: In this large and contemporaneous registry cohort, pre-eclampsia was not associated with worse graft survival or function. Preconception kidney function was the main determinant of graft survival.