Background: Delayed graft function (DGF) is common after kidney transplantation and heralds a worse prognosis. In patients with primary or enteric hyperoxaluria, the prevalence of DGF is high. Oxalic acid and its precursors are waste products that accumulate when kidney function decreases. We hypothesize that residual diuresis and accumulation of waste products influence the prevalence of DGF.

Methods: Patients who received a kidney transplant between September 2018 and January 2022 participated in the study. Concentrations of oxalic acid and its precursors were determined in pre-transplant blood samples. Data on residual diuresis and other recipient, donor or transplant related variables were collected.
Results: 496 patients were included, 154 were not on dialysis. Oxalic acid, glyoxylic acid, and glycolic acid concentrations were above the upper limit of normal in 98.8%, 100%, and 13% of patients, respectively. DGF, defined as dialysis in first week after transplantation, occurred in 157 patients. Multivariable binary logistic regression analysis demonstrated a significant influence of dialysis type, donor type, donor age, donor serum creatinine, and recipient BMI on the DGF risk. Glyoxylic acid concentration was significantly and directly proportionally related to the DGF risk, while residual diuresis and glycolic acid concentration were inversely proportionally related to this risk.

Conclusion: Low residual diuresis, high glyoxylic acid and low glycolic acid concentration independently influence the prevalence of DGF. Treatment aiming at preservation of residual diuresis and decreased accumulation of glyoxylic acid and other waste products as well as pre-emptive transplantation may decrease the prevalence of DGF.