Delayed graft function and the risk of death with graft function in living donor kidney transplant recipients

Background: The link between delayed graft function (DGF) and death with graft function (DWGF) in living donor kidney transplant recipients presently is unknown.

Study design: Retrospective cohort study.

Setting & participants: 44,630 adult living donor kidney recipients (first transplants only) in the US Renal Data System from January 1, 1994, to December 31, 2004.

Predictor: DGF, defined as the need for dialysis therapy in the first week after transplant.

Outcome: Time to DWGF.

Measurements: Kaplan-Meier curves were constructed to assess the impact of DGF on DWGF. Recipients with DGF were 1:1 propensity score matched to those without DGF, and time-dependent Cox proportional hazards models were used to examine factors associated with DWGF. Subgroup and sensitivity analyses also were conducted.

Results: DWGF occurred in 3,878 patients during 3.9 years' (median) follow-up. In patients with DGF, survival with graft function at 1, 3, 5, and 10 years was 91.9%, 86.8%, 81.6%, and 61.7%, respectively (in patients without DGF, these values were 98.0%, 95.2%, 91.6%, and 80.1%, respectively; P < 0.001 compared with the DGF group). In a fully adjusted time-dependent Cox model, HRs for DWGF in patients with DGF (vs without DGF) were 6.55 (95% CI, 4.78-8.97), 3.55 (95% CI, 2.46-5.11), 2.07 (95% CI, 1.53-2.81), and 1.48 (95% CI, 1.26-1.73) at 0-1, 1-3, 3-12, and longer than 12 months posttransplant, respectively. Propensity score analysis showed similar results. Inferences were unchanged after adjustment for kidney function and acute rejection at 6 months and 1 year posttransplant. Cardiovascular and infectious causes of DWGF were more prevalent in patients with DGF. The association was more marked in female recipients and robust to various sensitivity analyses.

Limitations: The impact of lesser decreases in early graft function could not be evaluated.

Conclusions: DGF is associated with an increased risk of DWGF in living donor kidney recipients. The mechanisms underlying this relation require further study.