Kidney delayed graft function (DGF) remains common after simultaneous liver–kidney (SLK) transplantation, yet its long-term implications for graft and recipient survival are incompletely defined.

Using the Scientific Registry of Transplant Recipients, we analyzed adult SLK recipients (2014-2025), stratified by kidney DGF, defined as receiving dialysis within the first postoperative week. To isolate the association between DGF and long-term outcomes and limit confounding due to primary non-function, recipient and graft survival analyses were conducted using a 90-day landmark analysis. Multivariable logistic regression identified predictors of DGF. Cox proportional hazards models evaluated death-censored kidney graft survival and overall recipient survival.

Among 3,268 SLK recipients, 890 (27.2%) developed kidney DGF. Independent predictors of DGF included pre-transplant dialysis (OR 2.79, 95% CI 2.31–3.38; p<0.001), higher model for end stage liver disease (MELD) score (OR 1.03 per point, 95% CI 1.01–1.04; p<0.001), metabolic-dysfunction-associated-steatohepatitis (MASH) etiology (OR 1.45, 95% CI 1.10–1.93; p=0.009), cold ischemia time (OR 1.02 per hour, 95% CI 1.01–1.04; p<0.001), post acuity circle era (OR 1.28, 95% CI 1.04–1.58; p=0.018), and higher KDRI (OR 1.12 per 0.1 increase, 95% CI 1.06–1.18; p<0.001). In the primary cohort, DGF was not independently associated with death-censored kidney graft failure (HR 1.30, 95% CI 0.80–2.11; p=0.29) but was associated with inferior recipient survival (HR 1.33, 95% CI 1.09–1.63; p=0.005). Sensitivity analyses in the unrestricted cohort confirmed the mortality association, while DGF was also associated with death-censored kidney graft failure (DCGF).

Kidney DGF after SLK transplantation is associated with recipient and donor risk factors and inferior long-term recipient survival, while its association with long-term kidney graft outcomes warrants further investigation.