The utilization of heterogeneous clinical criteria to define DGF has certain limitations. It will lead to delayed and sometimes inaccurate diagnosis of DGF. Hence a diagnostic test that identifies DGF reliably and early is necessary. Heterogeneity, in the definitions used for DGF, hinders the evolution of a diagnostic technique to identify DGF, which requires a gold standard definition. We are in need of a new definition that is uniformly accepted across the kidney transplant community. The new definition will be helpful in promoting better communication among transplant professionals and aids in comparing clinical studies of diagnostic techniques to identify DGF and thus may facilitate clinical trials of interventions for the treatment of DGF.

Current methods for predicting graft recovery after kidney transplantation are not reliable. We performed a prospective, multicenter, observational cohort study of deceased-donor kidney transplant patients to evaluate urinary neutrophil gelatinase-associated lipocalin (NGAL), IL-18, and kidney injury molecule-1 (KIM-1) as biomarkers for predicting dialysis within 1 wk of transplant and subsequent graft recovery. We collected serial urine samples for 3 d after transplant and analyzed levels of these putative biomarkers. We classified graft recovery as delayed graft function (DGF), slow graft function (SGF), or immediate graft function (IGF). Of the 91 patients in the cohort, 34 had DGF, 33 had SGF, and 24 had IGF. Median NGAL and IL-18 levels, but not KIM-1 levels, were statistically different among these three groups at all time points. ROC curve analysis suggested that the abilities of NGAL or IL-18 to predict dialysis within 1 wk were moderately accurate when measured on the first postoperative day, whereas the fall in serum creatinine (Scr) was not predictive. In multivariate analysis, elevated levels of NGAL or IL-18 predicted the need for dialysis after adjusting for recipient and donor age, cold ischemia time, urine output, and Scr. NGAL and IL-18 quantiles also predicted graft recovery up to 3 mo later. In summary, urinary NGAL and IL-18 are early, noninvasive, accurate predictors of both the need for dialysis within the first week of kidney transplantation and 3-mo recovery of graft function.

Deceased-donor kidneys with acute kidney injury (AKI) are often discarded due to fear of poor outcomes. We performed a multicenter study to determine associations of AKI (increasing admission-to-terminal serum creatinine by AKI Network stages) with kidney discard, delayed graft function (DGF) and 6-month estimated glomerular filtration rate (eGFR). In 1632 donors, kidney discard risk increased for AKI stages 1, 2 and 3 (compared to no AKI) with adjusted relative risks of 1.28 (1.08–1.52), 1.82 (1.45–2.30) and 2.74 (2.0–3.75), respectively. Adjusted relative risk for DGF also increased by donor AKI stage: 1.27 (1.09–1.49), 1.70 (1.37–2.12) and 2.25 (1.74–2.91), respectively. Six-month eGFR, however, was similar across AKI categories but was lower for recipients with DGF (48 [interquartile range: 31–61] vs. 58 [45–75] ml/min/1.73m2 for no DGF, P<0.001). There was significant favorable interaction between donor AKI and DGF such that 6-month eGFR was progressively better for DGF kidneys with increasing donor AKI (46 [29–60], 49 [32–64], 52 [36–59] and 58 [39–71] ml/min/1.73m2 for no AKI, stage 1, 2 and 3, respectively; interaction P=0.05). Donor AKI is associated with kidney discard and DGF, but given acceptable 6-month allograft function, clinicians should consider cautious expansion into this donor pool.

Objective To determine whether people who donate a kidney have an increased risk of cardiovascular disease.Design Retrospective population based matched cohort study.Participants All people who were carefully selected to become a living kidney donor in the province of Ontario, Canada, between 1992 and 2009. The information in donor charts was manually reviewed and linked to provincial healthcare databases. Matched non-donors were selected from the healthiest segment of the general population. A total of 2028 donors and 20 280 matched non-donors were followed for a median of 6.5 years (maximum 17.7 years). Median age was 43 at the time of donation (interquartile range 34-50) and 50 at the time of follow-up (42-58).

Despite having a much higher likelihood of DGF, obese transplant recipients have only a slightly increased risk of graft loss and experience similar survival to recipients with normal BMI.

Background While some studies have found an association between delayed graft function (DGF) after kidney transplantation and worse long-term outcomes, a causal relationship remains controversial. We investigated this relationship using an instrumental variables model (IVM), a quasi-randomization technique for drawing causal inferences. Methods We identified 80,690 adult, deceased-donor, kidney-only transplant recipients from the Scientific Registry of Transplant Recipients between 1997 and 2010. We used cold ischemia time (CIT) as an instrument to test the hypothesis that DGF causes death-censored graft loss and mortality at 1 and 5 years post-transplant, controlling for an array of characteristics known to affect patient and graft survival. We compared our IVM results to a multivariable linear probability model (LPM). Results DGF occurred in 27% of our sample. Graft loss rates at 1 and 5 years were 6% and 22%, respectively, and 1-year and 5-year mortality rates were 5% and 20%, respectively. In the LPM, DGF was associated with increased risk of both graft loss and mortality at 1 and 5 years (p<0.001). In the IVM, we found evidence suggesting a causal relationship between DGF and death-censored graft loss at both 1 year (13.5% increase; p<0.001) and 5 years (16.2% increase; p<0.001), and between DGF and mortality at both 1 year (7.1% increase; p<0.001) and 5 years (11.0% increase; p<0.01). Results were robust to exclusion of lower-quality as well as pumped kidneys and use of a creatinine-based definition for DGF. Conclusion Instrumental variables analysis supports a causal relationship between DGF and both graft loss and mortality.

Black living kidney donors are at higher risk of developing kidney disease than white donors. We examined the effect of the high-risk genotype on postdonation renal function in black living kidney donors and evaluated whether this genotype alters the association between donation and donor outcome. We grouped 136 black living kidney donors as high-risk (two risk alleles; =19; 14%) or low-risk (one or zero risk alleles;=117; 86%) genotype. Predonation characteristics were similar between groups, except for lower mean±SD baseline eGFR (CKD-EPI equation) in donors with the high-risk genotype (98±17 versus 108±20 ml/min per 1.73 m; =0.04). At a median of 12 years after donation, donors with the high-risk genotype had lower eGFR (57±18 versus 67±15 ml/min per 1.73 m; =0.02) and faster decline in eGFR after adjusting for predonation eGFR (1.19; 95% confidence interval, 0 to 2.3 versus 0.4; 95% confidence interval, 0.1 to 0.7 ml/min per 1.73 m per year, =0.02). Two donors developed ESRD; both carried the high-risk genotype. In a subgroup of 115 donors matched to 115 nondonors by genotype, we did not find a difference between groups in the rate of eGFR decline (=0.39) or any statistical interaction by status (=0.92). In conclusion, high-risk genotype in black living kidney donors associated with greater decline in postdonation kidney function. Trajectory of renal function was similar between donors and nondonors. The association between high-risk genotype and poor renal outcomes in kidney donors requires validation in a larger study.

Deceased-donor acute kidney injury (AKI) is associated with organ discard and delayed graft function, but data on longer-term allograft survival are limited. We performed a multicenter study to determine associations between donor AKI (from none to severe based on AKI Network stages) and all-cause graft failure, adjusting for donor, transplant, and recipient factors. We examined whether any of the following factors modified the relationship between donor AKI and graft survival: kidney donor profile index, cold ischemia time, donation after cardiac death, expanded-criteria donation, kidney machine perfusion, donor-recipient gender combinations, or delayed graft function. We also evaluated the association between donor AKI and a 3-year composite outcome of all-cause graft failure or estimated glomerular filtration rate ≤ 20 mL/min/1.73m2 in a subcohort of 30% of recipients. Among 2,430 kidneys transplanted from 1,298 deceased donors, 585 (24%) were from donors with AKI. Over a median follow-up of 3.7 years, there were no significant differences in graft survival by donor AKI stage. We found no evidence that pre-specified variables modified the effect of donor AKI on graft survival. In the subcohort, donor AKI was not associated with the 3-year composite outcome. Donor AKI was not associated with graft failure in this well-phenotyped cohort. Given the organ shortage, the transplant community should consider measures to increase utilization of kidneys from deceased donors with AKI.