The Prognostic Value of Kidney Transplant Center Report Cards

SRTR report cards provide the basis for quality measurement of US transplant centers. There is limited data evaluating the prognostic value of report cards, informing whether they are predictive of prospective patient outcomes. Using national SRTR data, we simulated report cards and calculated standardized mortality ratios (SMR) for kidney transplant centers over five distinct eras. We ranked centers based on SMR and evaluated outcomes for patients transplanted the year following reports. Recipients transplanted at the 50th, 100th and 200th ranked centers had 18% (AHR = 1.18, 1.13?1.22), 38% (AHR = 1.38, 1.28?1.49) and 91% (AHR = 1.91, 1.64?2.21) increased hazard for 1‐year mortality relative to recipients at the top‐ranked center. Risks were attenuated but remained significant for long‐term outcomes. Patients transplanted at centers meeting low‐performance criteria in the prior period had 40% (AHR = 1.40, 1.22?1.68) elevated hazard for 1‐year mortality in the prospective period. Centers' SMR from the report card was highly predictive (c‐statistics > 0.77) for prospective center SMRs and there was significant correlation between centers' SMR from the report card period and the year following (ρ = 0.57, p < 0.001). Although results do not mitigate potential biases of report cards for measuring quality, they do indicate strong prognostic value for future outcomes. Findings also highlight that outcomes are associated with center ranking across a continuum rather than solely at performance margins.

     

Living Donor Age and Kidney Transplant Outcomes

We assessed the relationship between living donor (LD) age and kidney survival in 1063 adults transplanted between 1980 and 2007. Increasing LD age was associated with lower kidney function (GFR) before and after transplantation and loss of GFR beyond 1 year. Increasing LD age was also associated with low‐moderate proteinuria posttransplant (151–1500 mg/day, p < 0.0001). By univariate analysis, reduced graft survival related to lower GFR at 1 year [HR = 0.925 (0.906–0.944), p < 0.0001], proteinuria [HR = 1.481 (1.333–1.646), p < 0.0001] and increasing LD age [HR = 1.271 (1.219–1.326), p = 0.001]. The impact of LD age on graft survival was noted particularly >4 years posttransplant and was modified by recipient age. Thus, compared to a kidney graft that was within 5 years of the recipient age, younger kidneys had a survival advantage [HR = 0.600 (0.380–0.949), p = 0.029] while older kidneys had a survival disadvantage [HR = 2.217 (1.507–3.261), p < 0.0001]. However, this effect was seen only in recipients <50 years old. By multivariate analysis, the relationship between LD age and graft survival was independent of GFR but related to proteinuria. In conclusion, LD age is an important determinant of long‐term graft survival, particularly in younger recipients. Older kidneys with reduced survival are identifiable by the development of proteinuria posttransplant.     

Ways to Boost Kidney Transplant Viability: A Real Need for the Best Use of Older Donors

Using kidneys from expanded criteria donors (ECD) increased transplant activity but resulted in a reduced graft survival. The relatively poor long-term outcome of ECD grafts may be the consequence of an imbalance between the number of viable nephrons supplied and the metabolic demand of the recipient. Providing more nephrons by dual transplants may improve outcomes but fails, per se, to confer the same benefit of single transplants from young donors. A biopsy-based score system has been presented by a panel of pathologists to assess whether kidneys from donors older than 60 years still contain enough viable nephrons to be made available for transplantation, and whether single or dual transplantation should be used. Allocating kidneys from older donors to a single or dual transplant on the basis of this scoring system allowed achieving a graft survival similar to that of single transplants from ideal donors and remarkably superior to that of single transplants from older donors not evaluated histologically before implantation. Thus, preimplantation histologic evaluation maximizes the success of ECD transplants and protects recipients from receiving organs at increased risk of premature failure. This may limit the number of patients who eventually must resume dialysis and need second transplants.     

Outcomes of Steroid‐Avoidance Protocols in Pediatric Kidney Transplant Recipients

Advances in immunosuppression have facilitated increased use of steroid‐avoidance protocols in pediatric kidney transplantation. To evaluate such steroid avoidance, a retrospective cohort analysis of pediatric kidney transplant recipients between 2002 and 2009 in the United Network for Organ Sharing database was performed. Outcomes (acute rejection and graft loss) in steroid‐based and steroid‐avoidance protocols were assessed in 4627 children who received tacrolimus and mycophenolate immunosuppression and did not have multiorgan transplants. Compared to steroid‐based protocols, steroid avoidance was associated with decreased risk of acute rejection at 6 months posttransplant (8.3% vs. 10.9%, p = 0.02) and improved 5‐year graft survival (84% vs. 78%, p < 0.001). However, patients not receiving steroids experienced less delayed graft function (p = 0.01) and pretransplant dialysis, were less likely to be African‐American and more frequently received a first transplant from a living donor (all p < 0.001). In multivariate analysis, steroid avoidance trended toward decreased acute rejection at 6 months, but this no longer reached statistical significance, and there was no association of steroid avoidance with graft loss. We conclude that, in clinical practice, steroid avoidance appears safe with regard to graft rejection and loss in pediatric kidney transplant recipients at lower immunologic risk.     

Kidney Transplant Rejection in Australia and New Zealand: Relationships Between Rejection and Graft Outcome

Although acute rejection rates have fallen over time, how this relates to graft outcomes is not known. Using data from the ANZDATA Registry, we examined associations of rejection within six months of transplantation with graft and patient outcomes among kidney-only transplants performed between April 1997 and December 2004 in Australia and New Zealand. Associations of biopsy histology with outcomes of the rejection episode were also examined. Outcomes were examined among 4325 grafts with 1961 rejection episodes in total. Crude rejection rates have fallen by one-third over that time, but rates of graft survival are constant. The occurrence of acute rejection was associated with an increased risk of graft loss after 6 months (HR, adjusted for donor and recipient characteristics, 1.69 [1.36-2.11], p<0.001). Late rejection (first rejection >or=90 days) was associated with higher risk of graft loss (adjusted HR 2.46 [1.70-3.56], p<0.001). Vascular rejection was also associated with a higher risk of graft loss 2.07 [95% CI 1.60-2.68], p<0.001. The occurrence of acute rejection is associated with an ongoing increased risk of graft loss, particularly if that episode occurred late or included vascular rejection. The reduced rates of rejection have not been associated with improved graft survival.     

Similar Outcomes with Different Rates of Delayed Graft Function May Reflect Center Practice, Not Center Performance

To better understand the implications for considering delayed graft function (DGF) as a performance measure, we compared outcomes associated with a 2- to 3-fold difference in the incidence of DGF at two transplant centers. We analyzed 5072 kidney transplantations between 1984 and 2006 at the University of Minnesota Medical Center (UMMC) and Hennepin County Medical Center (HCMC). In logistic regression the adjusted odds ratio for DGF at HCMC versus UMMC was 3.11 (95% Confidence Interval [CI]= 2.49–3.89) for deceased donors and 2.24 (CI = 1.45–3.47) for living donors. In Cox analysis of 4957 transplantations, slow graft function (SGF; creatinine ≥3.0 mg/dL [230 μmol/L] on day 5 without dialysis) was associated with graft failure at UMMC (Relative Risk [RR]= 1.43, CI = 1.25–1.64), but not HCMC (RR = 0.99, CI = 0.77–1.28). RR's of DGF were similar at both centers. Thus, the lower incidence of DGF at UMMC likely resulted in a higher incidence and higher risk of SGF compared to HCMC. Indeed, graft survival for recipients with DGF at HCMC was similar (p = 0.3741) to that of recipients with SGF at UMMC. We conclude that dialysis per se is likely not a cause of worse graft outcomes. A better definition is needed to measure early graft dysfunction and its effects across transplant programs.     

The Effects of Donor and Recipient Practices on Transplant Center Finances

Over the past several years we have noted a marked decrease in this profitability of our kidney transplant program. Our hypothesis is that this reduction in kidney transplant institutional profitability is related to aggressive donor and recipient practices. The study population included all adults with Medicare insurance who received a kidney transplant at our center between 1999 and 2005. Adopting the hospital perspective, multi-variate linear regression models to determine the independent effects of donor and recipient characteristics and era effects on total reimbursements and total hospital margin. We note statistically significant decreased medical center incremental margins in cases with ECDs (−$5887) and in cases of DGF (−4937). We also note an annual change in the medical center margin is independently associated with year and changes at a rate of −$5278 per year, related to both increasing costs and decreasing Medicare reimbursements. The financial loss associated with patient DGF and the use of ECD kidneys may resonate with other centers, and could hinder efforts to expand kidney transplantation within the United States. The Centers for Medicare and Medicaid Services (CMS) should consider risk-adjusted reimbursement for kidney transplantation.     

Acute Humoral Rejection in an ABO Compatible Combined Liver–Kidney Transplant—The Kidney Is Not Always Protected

Combined liver–kidney transplantation has become a common practice for the treatment of patients with concurrent end-stage renal disease and end-stage liver disease. Liver transplantation in the setting of multiorgan transplantation is thought to have a protective effect against humoral rejection even when a positive crossmatch is obtained prior to surgery. In most centers, a pre liver–kidney transplant crossmatch is rarely performed because of the known immunoprotective effect of the liver allograft. In this report, a case of acute humoral rejection in the kidney allograft after a combined liver–kidney transplant is described. Although humoral rejection was treated using plasmapheresis, intravenous immunoglobulin and rituximab, the kidney required 3 months to recover function and finally progressed to chronic allograft nephropathy. A heightened index of suspicion for acute humoral rejection of the renal allograft is necessary when performing combined liver–kidney transplants to highly sensitized patients due to previous organ transplants.     

Data-driven Derivation and Validation of Novel Phenotypes for Acute Kidney Transplant Rejection using Semi-supervised Clustering

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Predictability of Survival Models for Waiting List and Transplant Patients: Calculating LYFT

'Life years from transplant' (LYFT) is the extra years of life that a candidate can expect to achieve with a kidney transplant as compared to never receiving a kidney transplant at all. The LYFT component survival models (patient lifetimes with and without transplant, and graft lifetime) are comparable to or better predictors of long-term survival than are other predictive equations currently in use for organ allocation. Furthermore, these models are progressively more successful at predicting which of two patients will live longer as their medical characteristics (and thus predicted lifetimes) diverge. The C-statistics and the correlations for the three LYFT component equations have been validated using independent, nonoverlapping split-half random samples. Allocation policies based on these survival models could lead to substantial increases in the number of life years gained from the current donor pool.     

Pulsatile Perfusion Reduces the Incidence of Delayed Graft Function in Expanded Criteria Donor Kidney Transplantation

The use of expanded criteria donors (ECD) has been proposed to help combat the discrepancy between organ availability and need. ECD kidneys are associated with delayed graft function (DGF) and worse long-term survival. The aim of this study is to evaluate the impact of pulsatile perfusion (PP) on DGF and graft survival in transplanted ECD kidneys. From January 2000 to December 2003, 4618 ECD kidney-alone transplants were reported to the United Network for Organ Sharing. PP was performed on 912 renal allografts. The prognostic factors of DGF were analyzed using multivariate logistic regression analysis. Risk factors for reduced allograft viability were greater in donors and recipients of PP kidneys. Three-year graft survival of ECD kidneys preserved with PP was similar to cold storage (CS) kidneys. The incidence of DGF in PP kidneys was significantly lower than CS kidneys (26% vs. 36%, p < 0.001). Despite having a greater number of risk factors for reduced graft viability, the ECD-PP kidneys had similar graft survival compared to ECD-CS kidneys. The use of PP, by decreasing the incidence of DGF, may possibly lead to lower overall costs and increased utilization of donor kidneys.     

Duration of Donor Brain Death and its Influence on Kidney Graft Function

Short- and long-term rates of success after cadaveric kidney transplantation are significantly inferior to those from living related or unrelated donors. The major difference between cadaveric and living donation is brain death. In the present study we analyzed the influence of duration of brain death on short- and long-term graft function after cadaveric kidney transplantation. The interval between declaration of donor brain death and the beginning of the cold ischemia time before graft explantation was defined as duration of brain death (DBD). The influence of DBD on incidence of primary graft function and on duration of delayed kidney graft function as well as on kidney graft survival was analyzed in 1106 patients transplanted in one center and confirmed in a validation study of a second series of 752 kidney graft recipients from another transplant center. Kidney grafts harvested from donors with longer DBD (>470 min) exhibited a significantly higher incidence of primary graft function and a significantly better graft survival rate in comparison to kidneys from donors with a shorter DBD (<470 min). The tendency of these results could be confirmed in an independent validation study; however, the differences were not statistically significant. Although the dramatic hemodynamic and immunological changes in brain-dead donors may impair the quality of a potential kidney transplant, a longer duration of donor brain death did not deteriorate early and long-term kidney graft function.