Delayed graft function has comparable associations with early outcomes in primary and repeat transplant among deceased-donor kidney transplant recipients.

Background: Delayed graft function (DGF) is a common complication and is associated with worse outcomes among kidney transplant recipients (KTRs). There are various risk factors for DGF including previous transplant. We hypothesized that DGF among KTRs undergoing repeat transplant has a greater impact on outcomes compared to primary KTRs.

Methods: All deceased-donor KTRs between 01/2000 and 12/2020 at our center were included. Recipients were categorized as primary KTR or repeat KTR (any number of previous kidney transplants). Outcomes of interest included acute rejection, death-censored graft failure, and patient mortality within 12 months post-transplant.

Results: A total of 3137 deceased-donor KTRs were included; 2498(80%) were primary KTRs and 639(20%) were repeat KTRs. The rates of DGF were similar between the groups at 29% and 28%, respectively. Compared to KTRs without DGF, DGF was associated with a greater incidence of death and graft failure in both primary and repeat transplants; however, the risk of rejection was not significantly higher in repeat KTRs (p = 0.72). Comparing primary and repeat KTRs, there were no significant differences in either acute rejection (p-interaction = 0.11), death-censored graft failure (p-interaction = 0.38), or death (p-interaction = 0.37). In subgroup analysis among repeat KTRs with DGF, a repeat transplant with no prior DGF was associated with increased risk for death-censored graft failure and death but not for acute rejection. DGF in the prior transplant was protective against death-censored graft failure (HR: 0.07, 95% CI 0.005-0.98, p = 0.05) (p-interaction = 0.04), but this was not significantly associated with acute rejection or death.

Conclusion: DGF is associated with similar detrimental outcomes among primary and repeat KTRs.