Changes in Discard Rate After the Introduction of the Kidney Donor Profile Index (KDPI)

Utilization of Standard Criteria Donor and Expanded Criteria Donor Kidneys After Kidney Allocation System Implementation

BACKGROUND Implementation of the Kidney Allocation System (KAS) changed how kidneys are allocated and the information on which organ utilization decisions are based. We aimed to evaluate how KAS implementation changed kidney utilization and recipient outcomes. MATERIAL AND METHODS Using the United Network for Organ Sharing database, we identified recipients of kidney transplants from donors with kidney donor profile index (KDPI) of 61-90% in the 5-years pre- and 18-months post-KAS implementation and examined patient and graft survival and donor kidney discard rates based on standard criteria donor (SCD) or expanded criteria donor (ECD) status. RESULTS The proportion of ECD kidneys was unchanged pre- versus post-KAS. Post-KAS, SCD kidneys were less likely to be transplanted into young recipients while ECD kidneys were more likely to be transplanted. SCD kidneys in the post-KAS period conferred a 1.42 (95% CI: 1.18-1.73) times higher adjusted mortality and 2% lower 1-year survival (94.2% vs. 96.2%, P<0.001) but had unchanged graft failure compared to pre-KAS. For ECD kidneys, there was no difference in mortality or graft survival. The discard rate increased after KAS for both SCD and ECD kidneys (P<0.05) but was not different between SCD and ECD kidneys for any KDPI group. CONCLUSIONS After KAS implementation, patient survival for recipients of SCD kidneys was significantly worse.

Is the Kidney Donor Risk Index a Useful Tool in Non-US Patients?

Background:

Deceased donor kidney allocation in the United States is guided by the Kidney Donor Risk Index (KDRI). The generalizability of the KDRI beyond the United States has not been widely studied.

Objective:

To assess the generalizability of the KDRI in a cohort of non-US (Canadian) deceased donor kidney transplant recipients.

Design:

Population-based retrospective cohort study.

Setting:

Ontario, Canada.

Patients:

Recipients of deceased donor kidneys from January 1, 2005, to March 31, 2011.

Methods:

Using administrative data, we analyzed a cohort of deceased donor kidney recipients in Ontario, Canada. The Kaplan-Meier method and Cox proportional hazards models were used to assess the relationship between KDRI and the outcomes of graft loss and death. KDRI was modeled continuously and categorically. The ability of models with KDRI to predict recipient outcomes beyond donor age was also explored. Model discrimination was assessed using c-statistics, evaluated at 5 years of follow-up.

Results:

A total of 1299 consecutive deceased donor kidney transplant recipients were included. The median follow-up was 5.5 years. Mean donor age increased from 27 to 64 years across ascending KDRI quintiles. The adjusted relative hazards (95% confidence interval) for total graft loss from Q2 to Q5 (referent = Q1) were 1.27 (0.89-1.80), 1.58 (1.13-2.22), 1.43 (1.01-2.02), and 2.15 (1.54-2.99), respectively. Increased relative hazards across KDRI quintiles were also observed for death-censored graft loss, but not death with graft function. All-cause mortality was increased for the highest KDRI quintile only. In this cohort, a model with KDRI performed better than a model with donor age alone (P = .009).

Limitations:

Large health care databases may have precluded the complete capture of covariate data.

Conclusions:

In conclusion, the KDRI is generalizable to Canadian patients in Ontario and may help inform risk assessment beyond donor age. The performance of KDRI in other non-US settings, and the need for additional model refinement, warrants further study.

Machine perfusion and long-term kidney transplant recipient outcomes across allograft risk strata

Background

The use of machine perfusion (MP) in kidney transplantation lowers delayed graft function (DGF) and improves 1-year graft survival in some, but not all, grafts. These associations have not been explored in grafts stratified by the Kidney Donor Profile index (KDPI).

Methods

We analyzed 78 207 deceased-donor recipients using the Scientific Registry of Transplant Recipients data from 2006 to 2013. The cohort was stratified using the standard criteria donor/expanded criteria donor (ECD)/donation after cardiac death (DCD)/donation after brain death (DBD) classification and the KDPI scores. In each subgroup, MP use was compared with cold storage.

Results

The overall DGF rate was 25.4% and MP use was associated with significantly lower DGF in all but the ECD-DCD donor subgroup. Using the donor source classification, the use of MP did not decrease death-censored graft failure (DCGF), except in the ECD-DCD subgroup from 0 to 1 year {adjusted hazard ratio [aHR] 0.56 [95% confidence interval (CI) 0.32-0.98]}. In the ECD-DBD subgroup, higher DCGF from 1 to 5 years was noted [aHR 1.15 (95% CI 1.01-1.31)]. Also, MP did not lower all-cause graft failure except in the ECD-DCD subgroup from 0 to 1 year [aHR = 0.59 (95% CI 0.38-0.91)]. Using the KDPI classification, MP did not lower DCGF or all-cause graft failure, but in the ≤70 subgroup, higher DCGF [aHR 1.16 (95% CI 1.05-1.27)] and higher all-cause graft failure [aHR 1.10 (95% CI 1.02-1.18)] was noted. Lastly, MP was not associated with mortality in any subgroup.

Conclusions

Overall, MP did not lower DCGF. Neither classification better risk-stratified kidneys that have superior graft survival with MP. We question their widespread use in all allografts as an ideal approach to organ preservation.

Eversion endarterectomy of the deceased donor renal artery to prevent kidney discard

INTRODUCTION

Deceased donor (DD) kidneys exhibiting severe atherosclerosis involving the renal artery (RA) may represent a contraindication to kidney transplantation (KT).

METHODS

Eversion endarterectomy (EE) was performed as a salvage procedure to permit KT.

RESULTS

We identified 17 cases (1.2% of all DD KTs during the study period) involving EE of the DD RA. Thirteen (76.5%) kidneys were imported, and mean Kidney Donor Profile Index (KDPI) was 81%. Mean DD age was 59 years, mean RA plaque length was 1.7 cm, and mean glomerulosclerosis on biopsy was 10%. Mean recipient age was 64 years, and dialysis vintage was 32 months. With a mean follow-up of 36 months, actual patient and graft survival rates were both 76.5%. One patient died early without a technical problem. Of the remaining 16 patients, 2-year patient and graft survival rates were both 100%. There were no early or late vascular complications. The incidence of delayed graft function was 35%. Mean serum creatinine and GFR levels in patients with functioning grafts at latest follow-up were 1.8 mg/dL and 40 mL/min, respectively.

CONCLUSIONS

EE appears to be a safe and under-utilized procedure that may prevent discard of marginal donor kidneys and is associated with acceptable short-term outcomes.

Normothermic ex vivo kidney perfusion for graft quality assessment prior to transplantation

Normothermic ex vivo kidney perfusion (NEVKP) represents a novel approach for graft preservation and functional improvement in kidney transplantation. We investigated whether NEVKP also allows graft quality assessment before transplantation. Kidneys from 30-kg pigs were recovered in a model of heart-beating donation (group A) after 30 minutes (group B) or 60 minutes (group C) (n = 5/group) of warm ischemia. After 8 hours of NEVKP, contralateral kidneys were resected, grafts were autotransplanted, and the pigs were followed for 3 days. After transplantation, renal function measured based on peak serum creatinine differed significantly among groups (P < .05). Throughout NEVKP, intrarenal resistance was lowest in group A and highest in group C (P < .05). intrarenal resistance at the initiation of NEVKP correlated with postoperative renal function (P < .001 at NEVKP hour 1). Markers of acid-base homeostasis (pH, HCO₃^- , base excess) differed among groups (P < .05) and correlated with posttransplantation renal function (P < .001 for pH at NEVKP hour 1). Similarly, lactate and aspartate aminotransferase were lowest in noninjured grafts versus donation after circulatory death kidneys (P < .05) and correlated with posttransplantation kidney function (P < .001 for lactate at NEVKP hour 1). In conclusion, assessment of perfusion characteristics and clinically available perfusate biomarkers during NEVKP allows the prediction of posttransplantation graft function. Thus, NEVKP might allow decision-making regarding whether grafts are suitable for transplantation.

Kidney allograft offers: Predictors of turndown and the impact of late organ acceptance on allograft survival

There is growing interest in understanding patterns of organ acceptance and reducing discard. Little is known about how donor factors, timing of procurement, and geographic location affect organ offer decisions. We performed a retrospective cohort study of 47 563 deceased donor kidney match-runs from 2007 to 2013. Several characteristics unrelated to allograft quality were independently associated with later acceptance in the match-run: Public Health Service increased-risk donor status (adjusted odds ratio [aOR] 2.49, 95% confidence interval [CI] 2.29-2.69), holiday or weekend procurement (aOR 1.11, 95% CI 1.07-1.16), shorter donor stature (aOR 1.53 for <150 cm vs reference >180 cm, 95% CI 1.28-1.94), and procurement in an area with higher intensity of market competition (aOR 1.71, 95% CI 1.62-1.78) and with the longest waiting times (aOR 1.41, 95% CI 1.34-1.49). Later acceptance in the match-run was associated with delayed graft function but not all-cause allograft failure (adjusted hazard ratio 1.01, 95% CI 0.96-1.07). Study limitations include a lack of match-run data for discarded organs and the possibility of sequence inaccuracies for some nonlocal matches. Interventions are needed to reduce turndowns of viable organs, especially when decisions are driven by infectious risk, weekend or holiday procurement, geography, or other donor characteristics unrelated to allograft quality.

Is prolonged cold ischemia a contraindication to using kidneys from acute kidney injury donors?

To determine the impact of prolonged cold ischemia time (CIT) on the outcome of acute kidney injury (AKI) renal grafts, we therefore performed a single-center retrospective analysis in adult patients receiving kidney transplantation (KT) from AKI donors. Outcomes were stratified according to duration of CIT. A total of 118 patients receiving AKI grafts were enrolled. Based on CIT, patients were stratified as follows: (i) <20 hours, 27 patients; (ii) 20-30 hours, 52 patients; (iii) 30-40 hours, 30 patients; (iv) ≥40 hours, nine patients. The overall incidence of delayed graft function DGF was 41.5%. According to increasing CIT category, DGF rates were 30%, 42%, 40%, and 78%, respectively (P = .03). With a mean follow-up of 48 months, overall patient and graft survival rates were 91% and 81%. Death-censored graft survival (DCGS) rates were 84% and 88% for patients with and without DGF (P = NS). DCGS rates were 92% in patients with CIT <20 hours compared to 85% with CIT >20 hours (P = NS). In the nine patients with CIT >40 hours, the 4-year DCGS rate was 100%. We conclude that prolonged CIT in AKI grafts may not adversely influence outcomes and so discard of AKI kidneys because of projected long CIT is not warranted when donors are wisely triaged.

Characteristics and Performance of Unilateral Kidney Transplants from Deceased Donors

BACKGROUND AND OBJECTIVES

The fraction of kidneys procured for transplant that are discarded is rising in the United States. Identifying donors from whom only one kidney was discarded allows us to control for donor traits and better assess reasons for organ discard.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective cohort study using United Network for Organ Sharing Standard Transplant Analysis and Research file data to identify deceased donors from whom two kidneys were procured and at least one was transplanted. Unilateral pairs were defined as kidney pairs from a single donor from whom one kidney was discarded ("unilateral discard") but the other was transplanted ("unilateral transplant"). Organ quality was estimated using the Kidney Donor Risk Index and Kidney Donor Profile Index (KDPI). We compared all-cause graft failure rates for unilateral transplants to those for bilateral transplant Kaplan-Meier methods, and life table methodology was used to evaluate 1-, 2-, 3-, and 5-year survival rates of transplants from bilateral and unilateral donors.

RESULTS

Compared with bilateral donors (i.e., both kidneys transplanted) (n=80,584), unilateral donors (i.e., only one kidney transplanted) (n=7625) had higher mean terminal creatinine (1.3±2.1 mg/dl versus 1.1±0.9 mg/dl) and KDPI (67%±25% versus 42%±27%), were older, and were more likely to have hypertension, diabetes, hepatitis C, terminal stroke, or meet Centers for Disease Control and Prevention high-risk donor criteria. Unilateral discards were primarily attributed to factors expected to be similar in both kidneys from a donor: biopsy findings (22%), no interested recipient (13%), and donor history (7%). Anatomic abnormalities (14%), organ damage (11%), and extended ischemia (6%) accounted for about 30% of discards, but were the commonest reasons among low KDPI kidneys. Among kidneys with KDPI≥60%, there was an incremental difference in allograft survival over time (for unilateral versus bilateral transplants, 1-year survival: 83% versus 87%; 3-year survival: 69% versus 73%; 5-year survival: 51% versus 58%).

CONCLUSIONS

A large number of discarded kidneys were procured from donors whose contralateral kidneys were transplanted with good post-transplant outcomes.

Long-term outcome of renal transplantation from octogenarian donors: A multicenter controlled study

To assess whether biopsy-guided selection of kidneys from very old brain-dead donors enables more successful transplantations, the authors of this multicenter, observational study compared graft survival between 37 recipients of 1 or 2 histologically evaluated kidneys from donors older than 80 years and 198 reference-recipients of non-histologically evaluated single grafts from donors aged 60 years and younger (transplantation period: 2006-2013 at 3 Italian centers). During a median (interquartile range) of 25 (13-42) months, 2 recipients (5.4%) and 10 reference-recipients (5.1%) required dialysis (crude and donor age- and sex-adjusted hazard ratio [95% confidence interval] 1.55 [0.34-7.12], P = .576 and 1.41 [0.10-19.54], P = .798, respectively). Shared frailty analyses confirmed similar outcomes in a 1:2 propensity score study comparing recipients with 74 reference-recipients matched by center, year, donor, and recipient sex and age. Serum creatinine was similar across groups during 84-month follow-up. Recipients had remarkably shorter waiting times than did reference-recipients and matched reference-recipients (7.5 [4.0-19.5] vs 36 [19-56] and 40 [24-56] months, respectively, P < .0001 for both comparisons). Mean (± SD) kidney donor risk index was 2.57 ± 0.32 in recipients vs 1.09 ± 0.24 and 1.14 ± 0.24 in reference-recipients and matched reference-recipients (P < .0001 for both comparisons). Adverse events were similar across groups. Biopsy-guided allocation of kidneys from octogenarian donors permits further expansion of the donor organ pool and faster access to a kidney transplant, without increasing the risk of premature graft failure.

PROviding Better ACcess To ORgans: A comprehensive overview of organ-access initiatives from the ASTS PROACTOR Task Force

The American Society of Transplant Surgeons (ASTS) PROviding better Access To Organs (PROACTOR) Task Force was created to inform ongoing ASTS organ access efforts. Task force members were charged with comprehensively cataloguing current organ access activities and organizing them according to stakeholder type. This white paper summarizes the task force findings and makes recommendations for future ASTS organ access initiatives.

New Insights Into the Alleged Kidney Donor Profile Index Labeling Effect on Kidney Utilization

The Kidney Donor Profile Index (KDPI) became a driving factor in deceased donor kidney allocation on December 4, 2014, with the implementation of the kidney allocation system (KAS). On April 20, 2016, the annual recalibration of the Kidney Donor Risk Index into KDPI was incorrectly programmed in DonorNet, resulting in erroneously high KDPI values, by between 1 and 21 percentage points (e.g. actual KDPI of 70% was displayed as 86%). The error was corrected on May 19, 2016, <24 h after being recognized. During this 30-day period, the distribution of recipients largely resembled pre-KAS patterns. The observed discard rate of 22.9% was higher than the post-KAS average of 19.6% (odds ratio [OR]: 1.22) but far lower than the projected rate of 31.4% (OR: 1.96) based on the usual discard rate by KDPI relationship, suggesting clinicians and patients did not rely heavily on this single number (KDPI) in kidney-utilization decisions. Still, risk-adjusted analyses suggest the elevated discard rate was most likely attributable to the erroneously high KDPIs, not a shift in donor characteristics or random chance. The rise in discard rate was sharply higher for kidneys with inflated KDPI that crossed the 85% policy threshold (OR: 1.46; p = 0.049) versus those that did not (OR: 1.06; p = 0.631).

OPO Strategies to Prevent Unintended Use of Kidneys Exported for High PRA (>98% cPRA) Recipients

Since the advent of the Kidney Allocation System (KAS), matched candidates with high (>98%) panel reactive antibody (hPRA) are given priority over local candidates with lower PRA. This often leads to exporting of kidneys. Data for these kidneys are not detailed on routine reports. Twenty-two organ procurement organizations prospectively submitted data from August 2015 to July 2016, describing allocation practices of kidneys to hPRA patients and outcomes of these kidneys. Five hundred twenty out of 6924 procured kidneys were exported for hPRA recipients. Of these, 402 (77.3%) were transplanted into the intended recipient (IR); 100 (19.2%) were transplanted into unintended recipients (UR), and 18 (3.5%) were discarded. The most common reason for use in an UR was a positive crossmatch (XM) (63%). The most common reasons for discard were donor quality (44%) and ischemic time (39%). Prior to kidney export, when tissue crossmatching was done, 96.2% of the kidneys went to the IR, versus 80.7% following virtual CM, versus 56.7% when no crossmatching was performed (p < 0.0001). A significant number of kidneys exported for hPRA patients are not being used in the IR or are being discarded. The most common reason for this is positive tissue XM. We report that unintended use of the kidney was minimized when tissue was shipped and XM results were known prior to exporting the kidney.

Analysis of local versus imported expanded criteria donor kidneys: A single-center experience with 497 ECD kidney transplants

BACKGROUND

The value of importing expanded criteria donor (ECD) kidneys is uncertain.

METHODS

We retrospectively reviewed our single-center experience with ECD kidney transplants (KT).

RESULTS

Over 12.8 years, we performed 497 ECD KTs including 247 local and 250 imported from other donor service areas. The import ECD group had more donors (16% vs 9%) ≥ age 70, more zero human leukocyte antigen mismatches (14% vs 2%), more KTs with a cold ischemia time >30 hours (46% vs 19%), and fewer kidneys managed with pump preservation (78% vs 92%, all P≤.05) compared to the local ECD group. Mean Kidney Donor Profile Index were 80% import vs 84% local. With a mean follow-up of 55 months, actual patient and graft survival rates were 71% and 58% in import vs 76% and 58% in local ECD KTs, respectively. Death-censored graft survival rates were 70% in import vs 69% in local ECD KTs. Delayed graft function occurred in 28% import vs 23% local ECD KTs (P=NS) whereas the incidence of primary nonfunction was slightly higher with import ECD kidneys (4.8% vs 2.4%, P=.23).

CONCLUSIONS

Midterm outcomes are remarkably similar for import vs local ECD KTs, suggesting that broader sharing of ECD kidneys may improve utilization without compromising outcomes.

Impact of the Ratio of Visceral to Subcutaneous Adipose Tissue in Donor Nephrectomy Patients

OBJECTIVE

It was reported that a metabolic syndrome affected the remaining renal function after living donor nephrectomy. However, the measurement of waist circumference is unclear because it cannot distinguish between visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). We investigate the clinical correlation between body adipose tissue and renal function recovery after living donor nephrectomy.

METHODS

From July 2013 to February 2015, 75 living kidney donors were enrolled. The VAT and SAT were measured by preoperative computed tomography (CT) scan. Body mass index (BMI), VAT, SAT, and VAT-to-SAT ratio were analyzed according to a postoperative renal function recovery. Receiver operating characteristic (ROC) was performed to predict estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m² at postoperative 6 months for BMI, VAT, SAT, and VAT-to-SAT ratio.

RESULTS

The lowest value of eGFR (57.52 ± 11.20 mL/min/1.73 m²) was measured at postoperative day 7. There was no statistically significant difference in eGFR between 1 month and 3 months. BMI, VAT, SAT, and VAT-to-SAT ratio showed a statistically significant correlation with each other (Pearson correlation, P < .05). Also, the recovery time of eGFR was correlated with VAT-to-SAT ratio; it was significant at postoperative 1, 3, and 6 months. VAT-to-SAT ratio (0.654, 95% confidence interval 0.525-0.783, P = .024) had higher predictive value in ROC.

CONCLUSION

We developed a new variable to predict the value of lower eGFR (less than 60 mL/min/1.73 m²) at a postoperative 6 months in living kidney donor. According to a CT scan, VAT-to-SAT ratio can predict renal function recovery.

[New scores in renal transplantation: How can we use them?]

In renal transplant medicine, several scores have been recently developed in order to help decision-making in clinical practice. The aim of this update is to focus on these new scores that allow to better estimate the quality of the renal transplant, to refine the allocation policy, to help registration of old recipients on the waiting list, or to evaluate the risk to develop end-stage renal failure after living donation.

Proteins in Preservation Fluid as Predictors of Delayed Graft Function in Kidneys from Donors after Circulatory Death

BACKGROUND AND OBJECTIVES

Kidney transplantation is the preferred treatment for ESRD, and donor kidney shortage urges proper donor-recipient matching. Zero-hour biopsies provide predictive values for short- and long-term transplantation outcomes, but are invasive and may not reflect the entire organ. Alternative, more representative methods to predict transplantation outcome are required. We hypothesized that proteins accumulating in preservation fluid during cold ischemic storage can serve as biomarkers to predict post-transplantation graft function.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Levels of 158 proteins were measured in preservation fluids from kidneys donated after circulatory death (Maastricht category III) collected in two Dutch centers (University Medical Center Utrecht and Erasmus Medical Center Rotterdam) between 2013 and 2015. Five candidate biomarkers identified in a discovery set of eight kidneys with immediate function (IF) versus eight with delayed graft function (DGF) were subsequently analyzed in a verification set of 40 additional preservation fluids to establish a prediction model.

RESULTS

Variables tested for their contribution to a prediction model included five proteins (leptin, periostin, GM-CSF, plasminogen activator inhibitor-1, and osteopontin) and two clinical parameters (recipient body mass index [BMI] and dialysis duration) that distinguished between IF and DGF in the discovery set. Stepwise multivariable logistic regression provided a prediction model on the basis of leptin and GM-CSF. Receiver operating characteristic analysis showed an area under the curve (AUC) of 0.87, and addition of recipient BMI generated a model with an AUC of 0.89, outperforming the Kidney Donor Risk Index and the DGF risk calculator, showing AUCs of 0.55 and 0.59, respectively.

CONCLUSIONS

We demonstrate that donor kidney preservation fluid harbors biomarkers that, together with information on recipient BMI, predict short-term post-transplantation kidney function. Our approach is safe, easy, and performs better than current prediction algorithms, which are only on the basis of clinical parameters.

Kidney Donor Risk Index as the Predictor for the Short-term Clinical Outcomes After Kidney Transplant From Deceased Donor With Acute Kidney Injury

BACKGROUND

The Kidney Donor Risk Index (KDRI) scoring system for deceased donors has been widely introduced for postoperative evaluation of graft function. We analyzed the usefulness of the KDRI in deceased donors with acute kidney injury (AKI).

METHODS

Forty-nine recipients from deceased donors with AKI between January 2009 and December 2014 were reviewed retrospectively. Data collected from donor medical records included age, height, weight, hypertension or diabetes history, cause of death, serum creatinine (sCr), and donation after cardiac death. Graft function data including sCr, estimated glomerular filtration rate (eGFR), and acute rejection episodes were monitored for 1 year. Correlations between KDRI score and factors indicating graft function were analyzed. A cutoff value for KDRI score was calculated using a receiver operating characteristic (ROC) curve for significant graft function.

RESULTS

The mean ages of donors and recipients were 46.81 ± 13.13 and 47.69 ± 11.43, respectively. The mean KDRI score was 1.24 ± 0.40. Univariable analysis of KDRI score and factors indicating graft function indicated that sCr at 6 to 12 months, eGFR at 1 year, and slow graft function (SGF) had statistical significance. The ROC curve of KDRI score for SGF showed an optimal cutoff value of 1.20, with sensitivity of 69.2% and specificity of 69.4% (area under the curve = 0.75) in deceased donors with AKI.

CONCLUSIONS

KDRI score in deceased donors with AKI was correlated with postoperative graft values including eGFR and SGF. KDRI could be used as a predictor for the short-term clinical outcome after kidney transplant from deceased donor with AKI.

Local Expansion of Donation After Circulatory Death Kidney Transplant Activity Improves Waitlisted Outcomes and Addresses Inequities of Access to Transplantation

In the United Kingdom, donation after circulatory death (DCD) kidney transplant activity has increased rapidly, but marked regional variation persists. We report how increased DCD kidney transplant activity influenced waitlisted outcomes for a single center. Between 2002-2003 and 2011-2012, 430 (54%) DCD and 361 (46%) donation after brain death (DBD) kidney-only transplants were performed at the Cambridge Transplant Centre, with a higher proportion of DCD donors fulfilling expanded criteria status (41% DCD vs. 32% DBD; p = 0.01). Compared with U.K. outcomes, for which the proportion of DCD:DBD kidney transplants performed is lower (25%; p < 0.0001), listed patients at our center waited less time for transplantation (645 vs. 1045 days; p < 0.0001), and our center had higher transplantation rates and lower numbers of waiting list deaths. This was most apparent for older patients (aged >65 years; waiting time 730 vs. 1357 days nationally; p < 0.001), who received predominantly DCD kidneys from older donors (mean donor age 64 years), whereas younger recipients received equal proportions of living donor, DBD and DCD kidney transplants. Death-censored kidney graft survival was nevertheless comparable for younger and older recipients, although transplantation conferred a survival benefit from listing for only younger recipients. Local expansion in DCD kidney transplant activity improves survival outcomes for younger patients and addresses inequity of access to transplantation for older recipients.

Trends in Usage and Outcomes for Expanded Criteria Donor Kidney Transplantation in the United States Characterized by Kidney Donor Profile Index

There has been increasing concern in the kidney transplant community about the declining use of expanded criteria donors (ECD) despite improvement in survival and quality of life. The recent introduction of the Kidney Donor Profile Index (KDPI), which provides a more granular characterization of donor quality, was expected to increase utilization of marginal kidneys and decrease the discard rates. However, trends and practice patterns of ECD kidney utilization on a national level based on donor organ quality as per KDPI are not well known. We, therefore, performed a trend analysis of all ECD recipients in the United Network for Organ Sharing (UNOS) registry between 2002 and 2012, after calculating the corresponding KDPI, to enable understanding the trends of usage and outcomes based on the KDPI characterization. High-risk recipient characteristics (diabetes, body mass index ≥30 kg/m², hypertension, and age ≥60 years) increased over the period of the study (trend test p<0.001 for all). The proportion of ECD transplants increased from 18% in 2003 to a peak of 20.4% in 2008 and then declined thereafter to 17.3% in 2012. Using the KDPI >85% definition, the proportion increased from 9.4% in 2003 to a peak of 12.1% in 2008 and declined to 9.7% in 2012. Overall, although this represents a significant utilization of kidneys with KDPI >85% over time (p<0.001), recent years have seen a decline in usage, probably related to regulations imposed by Centers for Medicare & Medicaid Services (CMS).

When comparing the hazards of graft failure by KDPI, ECD kidneys with KDPI >85% have a slightly lower risk of graft failure compared to standard criteria donor (SCD) kidneys with KDPI >85%, with a hazard ratio (HR) of 0.95, a confidence interval (CI) of 0.94-0.96, and statistical significance of p<0.001. This indicates that some SCD kidneys may actually have a lower estimated quality, with a higher Kidney Donor Risk Index (KDRI), than some ECDs. The incidence of delayed graft function (DGF) in ECD recipients has significantly decreased over time from 35.2% in 2003 to 29.6% in 2011 (p=0.007), probably related to better understanding of the donor risk profile along with increased use of hypothermic machine perfusion and pretransplant biopsy to aid in optimal allograft selection.

The recent decline in transplantation of KDPI >85% kidneys probably reflects risk-averse transplant center behavior. Whether discard of discordant SCD kidneys with KDPI >85% has contributed to this decline remains to be studied.

Do Federal Regulations Have an Impact on Kidney Transplant Outcomes?

Transplantation is one of the most highly regulated fields in health care. An important component of transplant oversight is the performance assessment of transplant centers as measured by 1-year patient and graft survival outcomes. The use of the Organ Procurement and Transplantation Network and Scientific Registry of Transplant Recipients flagging mechanism for quality improvement as criteria for Center for Medicare and Medicaid Services certification has resulted in greater importance in transplant program operations. Although supporters of this program of encouraging Quality Assurance and Performance Improvement point to improved survival outcomes for more than the decade, others assert that the oversight is unnecessarily punitive, results in tremendous resource utilization, and discourages innovation. Data exist to support an inhibitory effect on national transplant volume. Although survival outcomes are risk adjusted, limitations on national data collection prevent several important risks from being incorporated into the models. This has led to the consensus that many transplant centers have become increasingly risk averse in this environment, which may indirectly reduce access to transplant for candidates who could still benefit from transplantation. Recently enacted modifications to performance evaluation by Center for Medicare and Medicaid Services and the Organ Procurement and Transplantation Network appear to acknowledge these concerns and have the potential to recalibrate transplant center focus away from first-year outcomes and more toward expanding transplant volume, innovation, and overall improvements in care.