title: Trends in Usage and Outcomes for Expanded Criteria Donor Kidney Transplantation in the United States Characterized by Kidney Donor Profile Index.
abstract: 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.
authors.affiliation: Surgery, Duke University Medical Center.
authors.forename: Aparna
authors.initials: A
authors.lastname: Rege
authors.affiliation: Health Outcomes Research & Biostatistics, CTI Clinical Trial and Consulting.
authors.forename: Bill
authors.initials: B
authors.lastname: Irish
authors.affiliation: Surgery, Duke University Medical Center.
authors.forename: Anthony
authors.initials: A
authors.lastname: Castleberry
authors.affiliation: Surgery, Duke University Medical Center ; Division of Abdominal Transplantation, Duke University Medical Center.
authors.forename: Deepak
authors.initials: D
authors.lastname: Vikraman
authors.affiliation: Transplant Nephrology, Duke University Medical Center.
authors.forename: Scott
authors.initials: S
authors.lastname: Sanoff
authors.affiliation: Surgery, Duke University Medical Center ; Division of Abdominal Transplantation, Duke University Medical Center.
authors.forename: Kadiyala
authors.initials: K
authors.lastname: Ravindra
authors.affiliation: Surgery, Duke University Medical Center.
authors.forename: Bradley
authors.initials: B
authors.lastname: Collins
authors.affiliation: Surgery, Duke University Medical Center ; Division of Abdominal Transplantation, Duke University Medical Center.
authors.forename: Debra
authors.initials: D
authors.lastname: Sudan
keywords: clinical outcomes; deceased donor kidneys; expanded criteria donor; kdpi: kidney donor profile index; kdri: kidney donor risk index; kidney graft survival; kidney transplant; post-transplant mortality; standard criteria donor