Impact of delayed graft function on cadaveric kidney transplant outcome

Delayed Graft Function in Kidney Transplantation

Context:

Although kidney transplantations are routinely performed at many centers in Turkey, the incidence and risk factors associated with delayed graft function (DGF) here have not yet been well defined.

Objective:

The aim of this study is to evaluate the incidence and risk factors of DGF and its impact on early graft function.

Design:

The medical charts of 154 adult patients who underwent deceased donor kidney transplantation between 2000 and 2014 in a single center were reviewed retrospectively.

Setting:

Delayed graft function-related risk factors for donors, recipients, and the transplant surgery itself were analyzed, and their relation with graft function was evaluated.

Main Outcomes Measures:

The median recipient age was 39 years. The median cold ischemia time (CIT) was 840 minutes (14 hours). The incidence of DGF and acute rejection were 57.8% and 8.4%, respectively. Higher serum creatinine levels at 3, 6, and 12 months were observed in patients with DGF compared to other patients without DGF ( P < .05). Patients with DGF had poor graft function (glomerular filtration rate ≤ 50) at 3 and 6 months ( P < .05), but these correlations were not seen at 12 months ( P = not significant).

Results:

This study showed that DGF was a common and serious problem associated with poor graft functions at 3, 6, and 12 months after transplantation. Extra effort to shorten CIT as an independent risk factor for DGF could have protective effect on graft functions.

Delayed graft function and the risk of acute rejection in the modern era of kidney transplantation

Delayed graft function (DGF) is commonly considered a risk factor for acute rejection, although this finding has not been uniformly observed across all studies. The link between DGF and acute rejection may have changed over time due to advances in immunosuppression and medical management. Here we conducted a cohort study of 645 patients over 12 years to evaluate the association of DGF and biopsy-proven acute rejection (BPAR) in a modern cohort of kidney transplant recipients. DGF was defined as the need for at least one dialysis session in the first week after kidney transplantation. The 1-, 3-, and 5-year cumulative probabilities of BPAR were 16.0, 21.8, and 22.6% in the DGF group, significantly different from the 10.1, 12.4, and 15.7% in the non-DGF group. In multivariable Cox proportional hazards model, the adjusted relative hazard for BPAR in DGF (vs. no DGF) was 1.55 (95% confidence interval (CI): 1.03, 2.32). This association was generally robust to different definitions of DGF. The relative hazard was also similarly elevated for T-cell- or antibody-mediated BPAR (1.52 (0.92, 2.51) and 1.54 (0.85, 2.77), respectively). Finally, the association was consistent across clinically relevant subgroups. Thus DGF remains an important risk factor for BPAR in a contemporary cohort of kidney transplant recipients. Interventions to reduce the risk of DGF and/or its aftereffects remain of paramount importance to improve kidney transplant outcomes.

The effect of delayed graft function on graft and patient survival in kidney transplantation: an approach using competing events analysis

OBJECTIVE

In kidney transplantation, the impact of delayed graft function (DGF) on long-term graft and patient survival is controversial. We examined the impact of DGF on graft and recipient survival by accounting for the possibility that death with graft function may act as a competing risk for allograft failure.

STUDY DESIGN AND SETTING

We used data from 1281 adult primary deceased-donor kidney recipients whose allografts functioned at least 1 year.

RESULTS

The probability of graft loss occurrence is overestimated using the complement of Kaplan-Meier estimates (1-KM). Both the cause-specific Cox proportional hazard regression model (standard Cox) and the subdistribution hazard regression model proposed by Fine and Gray showed that DGF was associated with shorter time to graft failure (csHR = 2.0, P = 0.002; sHR = 1.57, P = 0.009), independent of acute rejection (AR) and after adjusting for traditional factors associated with graft failure. Regarding patient survival, DGF was a predictor of patient death using the cause-specific Cox model (csHR = 1.57, P = 0.029) but not using the subdistribution model.

CONCLUSIONS

The probability of graft loss from competing end points should not be reported with the 1-KM. Application of a regression model for subdistribution hazard showed that, independent of AR, DGF has a detrimental effect on long-term graft survival, but not on patient survival.

Delayed graft function is not associated with an increased incidence of renal allograft rejection

Delayed graft function (DGF) is considered as a risk factor for renal allograft rejection, but this association might be confounded by diagnostic biases (e.g., higher biopsy frequency in patients with DGF, inclusion of clinically diagnosed rejection episodes, and limited details on the rejection phenotype). This retrospective study including 329 deceased donor transplantations aimed to clarify a causal relationship between DGF and rejection. DGF occurred in 93/329 recipients (28%), whereas immediate graft function (IGF) in 236/329 recipients (72%). The percentage of patients with ≥1 allograft biopsy within the first year post-transplant was similar between the DGF and IGF group (96% vs. 94%; p=0.60). The cumulative one-yr incidence of biopsy-proven clinical (35% vs. 34%; p=0.62) and combined (sub)clinical rejection (58% vs. 60%; p=0.79) was not different between the two groups. Furthermore, there were no differences regarding rejection phenotypes/severities and time frame of occurrence. By multivariable Cox regression analysis, donor-specific HLA antibodies, younger recipient age, and immunosuppressive regimens were independent predictors for clinical rejection, while DGF was not. These results in an intermediate sized, but thoroughly investigated patient population challenge the concept that DGF is a risk factor for rejection and highlights the need for additional studies in this regard.

Associations of pre-transplant anemia management with post-transplant delayed graft function in kidney transplant recipients

BACKGROUND

Delayed graft function (DGF) complicates kidney allograft outcomes in the immediate post-transplantation period. We hypothesized that in hemodialysis patients more severe anemia, iron deficiency, the requirement for higher doses of erythropoietin-stimulating agents (ESA), or blood transfusions prior to transplantation are associated with higher risk of DGF.

METHODS

Linking five-yr hemodialysis patient data of a large dialysis organization to the Scientific Registry of Transplant Recipients, we identified 11 836 hemodialysis patients. Using logistic regression analyses we examined the association between pre-transplant parameters and post-transplant DGF.

RESULTS

Patients were 49 ± 14 (mean ± SD) yr old and included 38% women, 27% blacks, and 26% diabetics. After adjusting for relevant covariates, pre-transplant blood transfusion was associated with 33% higher DGF risk (odds ratio [OR] = 1.33; 95% confidence interval [CI]: 1.19-1.48); and each 5000 U/wk increase of pre-transplant ESA dose with 5% higher DGF (OR = 1.05; 95% CI: 1.02-1.09). Compared to pre-transplant blood hemoglobin of 12-12.99 g/dL, there was 25% higher risk of DGF with blood hemoglobin 10-10.99 g/dL (OR = 1.25; 95% CI: 1.01-1.55), whereas blood hemoglobin ≥13 g/dL exhibited 15% higher risk of DGF (OR = 1.15; 95% CI: 0.98-1.34).

CONCLUSIONS

Pre-transplant blood transfusion, higher ESA dose, and either high or low blood hemoglobin but not iron markers are associated with higher risk of DGF.

Associations of pretransplant serum albumin with post-transplant outcomes in kidney transplant recipients

The association between pretransplant serum albumin concentration and post-transplant outcomes in kidney transplant recipients is unclear. We hypothesized that in transplant-waitlisted hemodialysis patients, lower serum albumin concentrations are associated with worse post-transplant outcomes. Linking the 5-year patient data of a large dialysis organization (DaVita) to the Scientific Registry of Transplant Recipients, we identified 8961 hemodialysis patients who underwent first kidney transplantation. Mortality or graft failure and delayed graft function (DGF) risks were estimated by Cox regression (hazard ratio [HR]) and logistic regression (Odds ratio [OR]), respectively. Patients were 48 ± 13 years old and included 37% women and 27% diabetics. The higher pretransplant serum albumin was associated with lower mortality, graft failure and DGF risk even after multivariate adjustment for case-mix, malnutrition-inflammation complex and transplant related variable. Every 0.2 g/dL higher pretransplant serum albumin concentration was associated with 13% lower all-cause mortality (HR = 0.87 [95% confidence interval: 0.82-0.93]), 17% lower cardiovascular mortality (HR = 0.83[0.74-0.93]), 7% lower combined risk of death or graft failure (HR = 0.93[0.89-0.97]) and 4% lower DGF risk (OR = 0.96[0.93-0.99]). Hence, lower pretransplant serum albumin level is associated with worse post-transplant outcomes. Clinical trials to examine interventions to improve nutritional status in transplant-waitlisted hemodialysis patients and their impacts on post-transplant outcomes are indicated.

Higher recipient body mass index is associated with post-transplant delayed kidney graft function

To examine whether a higher body mass index (BMI) in kidney recipients is associated with delayed graft function (DGF), we analyzed data from 11,836 hemodialysis patients in the Scientific Registry of Transplant Recipients who underwent kidney transplantation. The patient cohort included women, blacks, and diabetics; the average age was 49 years; and the mean BMI was 26.8 kg/m(2). After adjusting for relevant covariates, multivariate logistic regression analyses found that one standard deviation increase in pretransplant BMI was associated with a higher risk of DGF (odds ratio (OR) 1.35). Compared with patients with a pretransplant BMI of 22-24.99 kg/m(2), overweight patients (BMI 25-29.99 kg/m(2)), mild obesity patients (BMI 30-34.99 kg/m(2)), and moderate-to-severe obesity patients (BMI 35 kg/m(2) and over) had a significantly higher risk of DGF, with ORs of 1.30, 1.42, and 2.18, respectively. Similar associations were found in all subgroups of patients. Hence, pretransplant overweight or obesity is associated with an incrementally higher risk of DGF.

Association between delayed graft function and allograft and patient survival: a systematic review and meta-analysis

BACKGROUND

Delayed graft function (DGF) is a common complication of renal transplantation. The short-term consequences of DGF are well known, but the long-term relationship between DGF and patient and graft survival is controversial in the published literature. We conducted a systematic review and meta-analysis to precisely estimate these relationships.

METHODS

We performed a literature search for original studies published through March 2007 pertaining to long-term (>6 months) outcomes of DGF. The primary outcome was graft survival. Secondary outcomes were patient survival, acute rejection and kidney function.

RESULTS

When compared to patients without DGF, patients with DGF had a 41% increased risk of graft loss (RR 1.41, 95% CI 1.27-1.56) at 3.2 years of follow-up. There was no significant relationship between DGF and patient survival at 5 years (RR 1.14, 95% CI 0.94-1.39). The mean creatinine in the non-DGF group was 1.6 mg/dl. Patients with DGF had a higher mean serum creatinine (0.66 mg/dl, 95% CI 0.57-0.74) compared to patients without DGF at 3.5 years of follow-up. DGF was associated with a 38% relative increase in the risk of acute rejection (RR 1.38, 95% CI 1.29-1.47).

CONCLUSION

The results of this meta-analysis emphasize and quantify the long-term detrimental association between DGF and important graft outcomes like graft survival, acute rejection and renal function. Efforts to prevent and treat DGF should be aggressively investigated in order to improve graft survival given the deficit in the number of kidney donors.

Long-term renal outcomes after delayed graft function

Delayed graft function (DGF) describes dysfunction of the kidney allograft immediately after transplantation and is the most common complication in the immediate posttransplantation period. Although a standardized definition for DGF is lacking, it is most commonly defined as the need for dialysis within the first week after transplant. DGF is caused by a variety of factors related to the donor and recipient as well as organ procurement techniques. The occurrence of DGF affects both allograft and patient outcomes. In addition to prolonging hospital stay and increasing the costs associated with transplantation, DGF is associated with an increased incidence of acute rejection after transplantation and is associated with poorer long-term graft outcomes. Both immunologic and nonimmunologic mechanisms contribute to DGF. The risk factors for DGF that have been identified are reviewed as well as the impact of DGF on long-term outcomes.

Marked variation in the definition and diagnosis of delayed graft function: a systematic review

BACKGROUND

The term delayed graft function (DGF) is commonly used to describe the need for dialysis after receiving a kidney transplant. DGF increases morbidity after transplantation, prolongs hospitalization and may lead to premature graft failure. Various definitions of DGF are used in the literature without a uniformly accepted technique to identify DGF.

METHODS

We performed a systematic review of the literature to identify all of the different definitions and diagnostic techniques to identify DGF.

RESULTS

We identified 18 unique definitions for DGF and 10 diagnostic techniques to identify DGF.

CONCLUSIONS

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.

Effect of Delayed Graft Function in Hypersensitized Kidney Transplant Recipients

There is increased evidence about the deleterious effect of delayed graft function (DGF) in both short- and long-term kidney graft outcome. Among the mechanisms involved in the production of DGF, immune factors play a role, especially in the level of hypersensitization. From the 1389 patients transplanted at our hospital until November 2004, it has been found that the presence of moderate and high levels of sensitization, as measured by panel-reactive antibodies, is a risk factor for suffering from DGF. Further, DGF was associated with poor graft survival, and the risk was even higher when DGF was combined with moderate/high panel-reactive antibodies. Recent data demonstrate the usefulness of intravenous immunoglobulins in the management of hypersensitized patients in terms of short-term outcome. It remains to be demonstrated whether this therapy is able to ameliorate the higher ischemic injury that kidneys undergo from these immunologically high-risk patients.

Creatinine reduction ratio on post-transplant day two as criterion in defining delayed graft function

Delayed graft function (DGF) is a common complication after renal transplant, affecting its outcome. A common definition of DGF is the need for dialysis within the first week of transplantation, but this criterion has its drawbacks. We tried to validate an earlier and better defined parameter of DGF based on the creatinine reduction ratio on post-transplant day 2 (CRR2). We analyzed the clinical charts of 291 cadaver kidney recipients to compare the outcome of patients with immediate graft function (IGF), dialyzed patients (D-DGF) and nondialyzed CRR2-defined DGF patients (ND-DGF) and to identify risk factors for D-DGF and ND-DGF. Creatinine reduction ratio on post-transplant day 2 correlates significantly with renal function during the first year. Patients with IGF have significantly better renal function throughout the first year and better graft survival than patients with D-DGF and ND-DGF, while we found no differences either in renal function from days 30-365 or in graft survival between D-DGF and ND-DGF patients. Defining DGF by CRR2 allows an objective and quantitative diagnosis after transplantation and can help to improve post-transplant management. Creatinine reduction ratio on post-transplant day 2 correlates with renal function throughout the first year. The worse survival in the ND-DGF group is an important finding and a major advantage of the CRR2 criterion.