American Journal of Kidney Diseases

Referral and Evaluation for Kidney Transplantation Following Implementation of the 2014 National Kidney Allocation System

Published:March 14, 2022DOI:

      Rationale & Objective

      The national kidney allocation system (KAS) implemented in December 2014 in the United States redefined the start of waiting time from the time of waitlisting to the time of kidney failure. Waitlisting has declined post-KAS, but it is unknown if this is due to transplant center practices or changes in dialysis facility referral and evaluation. The purpose of this study was to assess the impact of the 2014 KAS policy change on referral and evaluation for transplantation among a population of incident and prevalent patients with kidney failure.

      Study Design

      Cohort study.

      Setting & Participants

      37,676 incident (2012-2016) patients in Georgia, North Carolina, and South Carolina identified within the US Renal Data System at 9 transplant centers and followed through December 2017. A prevalent population of 6,079 patients from the same centers receiving maintenance dialysis in 2012 but not referred for transplantation in 2012.


      KAS era (pre-KAS vs post-KAS).


      Referral for transplantation, start of transplant evaluation, and waitlisting.

      Analytical Approach

      Multivariable time-dependent Cox models for the incident and prevalent population.


      Among incident patients, KAS was associated with increased referrals (adjusted HR, 1.16 [95% CI, 1.12-1.20]) and evaluation starts among those referred (adjusted HR, 1.16 [95% CI, 1.10-1.21]), decreased overall waitlisting (adjusted HR, 0.70 [95% CI, 0.65-0.76]), and lower rates of active waitlisting among those evaluated compared to the pre-KAS era (adjusted HR, 0.81 [95% CI, 0.74-0.90]). Among the prevalent population, KAS was associated with increases in overall waitlisting (adjusted HR, 1.74 [95% CI, 1.15-2.63]) and active waitlisting among those evaluated (adjusted HR, 2.01 [95% CI, 1.16-3.49]), but had no significant impact on referral or evaluation starts among those referred.


      Limited to 3 states, residual confounding.


      In the southeastern United States, the impact of KAS on steps to transplantation was different among incident and prevalent patients with kidney failure. Dialysis facilities referred more incident patients and transplant centers evaluated more incident patients after implementation of KAS, but fewer evaluated patients were placed onto the waitlist. Changes in dialysis facility and transplant center behaviors after KAS implementation may have influenced the observed changes in access to transplantation.

      Index Words

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        • Johansen K.L.
        • Chertow G.M.
        • Foley R.N.
        • et al.
        US Renal Data System 2020 annual data report: epidemiology of kidney disease in the United States.
        Am J Kidney Dis. 2021; 77: A7-A8
        • Danovitch G.M.
        Options for patients with kidney failure.
        in: Danovitch G.M. Handbook of Kidney Transplantation. 2nd ed. Lippincott Williams & Wilkins, Philadelphia2005: 1-22
        • Tonelli M.
        • Wiebe N.
        • Knoll G.
        • et al.
        Systematic review: kidney transplantation compared with dialysis in clinically relevant outcomes.
        Am J Transplant. 2011; 11: 2093-2109
        • Hart A.
        • Smith J.M.
        • Skeans M.A.
        • et al.
        OPTN/SRTR 2017 annual data report: kidney.
        Am J Transplant. 2019; 19: 19-123
        • Patzer R.E.
        • McClellan W.M.
        Influence of race, ethnicity and socioeconomic status on kidney disease.
        Nat Rev Nephrol. 2012; 8: 533-541
        • Schold J.D.
        • Mohan S.
        • Huml A.
        • et al.
        Failure to advance access to kidney transplantation over two decades in the United States.
        J Am Soc Nephrol. 2021; 32: 913-926
        • King K.L.
        • Husain S.A.
        • Schold J.D.
        • et al.
        Major variation across local transplant centers in probability of kidney transplant for wait-listed patients.
        J Am Soc Nephrol. 2020; 31: 2900-2911
        • Organ Procurement and Transplantation Network
        Organ Procurement and Transplantation Network (OPTN) policies.
        United Network for Organ Sharing, 2014
        • Glasgow R.E.
        • Vogt T.M.
        • Boles S.M.
        Evaluating the public health impact of health promotion interventions: the RE-AIM framework.
        Am J Public Health. 1999; 89: 1322-1327
        • Zhang X.
        • Melanson T.A.
        • Plantinga L.C.
        • et al.
        Racial/ethnic disparities in waitlisting for deceased donor kidney transplantation 1 year after implementation of the new national kidney allocation system.
        Am J Transplant. 2018; 18: 1936-1946
        • Patzer R.E.
        • McPherson L.
        • Wang Z.
        • et al.
        Dialysis facility referral and start of evaluation for kidney transplantation among patients treated with dialysis in the Southeastern United States.
        Am J Transplant. 2020; 20: 2113-2125
        • Schultz L.R.
        • Peterson E.L.
        • Breslau N.
        Graphing survival curve estimates for time-dependent covariates.
        Int J Methods Psychiatr Res. 2002; 11: 68-74
        • Cantor A.B.
        A test of the association of a time-dependent state variable to survival.
        Comput Methods Programs Biomed. 1995; 46: 101-105
        • McPherson L.
        • Basu M.
        • Gander J.
        • et al.
        Decisional conflict between treatment options among end-stage renal disease patients evaluated for kidney transplantation.
        Clin Transplant. 2017; 31e12991
        • Poguntke I.
        • Schumacher M.
        • Beyersmann J.
        • Wolkewitz M.
        Simulation shows undesirable results for competing risks analysis with time-dependent covariates for clinical outcomes.
        BMC Med Res Methodol. 2018; 18: 79
      1. R: A Language and Environment for Statistical Computing [computer program]. R Foundation for Statistical Computing; 2021.
        • Kassambara A.
        • Kosinski M.
        • Biecek P.
        • Scheipl F.
        survminer: Drawing Survival Curves using 'ggplot2' [computer program]. CRAN; 2021.
        • Wickham H.
        • Chang W.
        • Henry L.
        • et al.
        ggplot2: Elegant Graphics for Data Analysis [computer program]. CRAN; 2016.
        • Fox J.
        The R Commander: a basic-statistics graphical user interface to R.
        J Stat Softw. 2005; 14: 1-42
        • Kanda Y.
        Investigation of the freely available easy-to-use software ‘EZR’ for medical statistics.
        Bone Marrow Transplant. 2013; 48: 452-458
        • Gander J.C.
        • Zhang X.
        • Plantinga L.
        • et al.
        Racial disparities in preemptive referral for kidney transplantation in Georgia.
        Clin Transplant. 2018; 32e13380
        • Schold J.D.
        • Buccini L.D.
        • Poggio E.D.
        • Flechner S.M.
        • Goldfarb D.A.
        Association of candidate removals from the kidney transplant waiting list and center performance oversight.
        Am J Transplant. 2016; 16: 1276-1284
        • Schold J.D.
        • Arrigain S.
        • Flechner S.M.
        • et al.
        Dramatic secular changes in prognosis for kidney transplant candidates in the United States.
        Am J Transplant. 2019; 19: 414-424
        • Centers for Medicare & Medicaid Services
        ESRD Network Organizations. 2019.
        • Patzer R.E.
        • Paul S.
        • Plantinga L.
        • et al.
        A randomized trial to reduce disparities in referral for transplant evaluation.
        J Am Soc Nephrol. 2017; 28: 935-942
        • Husain S.A.
        • King K.L.
        • Pastan S.
        • et al.
        Association between declined offers of deceased donor kidney allograft and outcomes in kidney transplant candidates.
        JAMA Netw Open. 2019; 2e1910312
        • Patzer R.E.
        • Basu M.
        • Smith K.D.
        • et al.
        Awareness of the new kidney allocation system among United States dialysis providers with low waitlisting.
        Am J Nephrol. 2018; 47: 115-119
        • Patzer R.E.
        • Smith K.
        • Basu M.
        • et al.
        The ASCENT (Allocation System Changes for Equity in Kidney Transplantation) Study: a randomized effectiveness-implementation study to improve kidney transplant waitlisting and reduce racial disparity.
        Kidney Int Rep. 2017; 2: 433-441
        • Magua W.
        • Basu M.
        • Pastan S.O.
        • et al.
        Effect of the ASCENT intervention to increase knowledge of kidney allocation policy changes among dialysis providers.
        Kidney Int Rep. 2020; 5: 1422-1431
        • Waterman A.D.
        • Peipert J.D.
        An Explore Transplant group randomized controlled education trial to increase dialysis patients' decision-making and pursuit of transplantation.
        Prog Transplant. 2018; 28: 174-183
        • Centers for Medicare & Medicaid Services
        Technical Expert Panel Charter. Practitioner Level Measurement of Effective Access to Kidney Transplantation. 2021.
        • Chandraker A.
        • Andreoni K.A.
        • Gaston R.S.
        • et al.
        Time for reform in transplant program-specific reporting: AST/ASTS transplant metrics taskforce.
        Am J Transplant. 2019; 19: 1888-1895
        • Patzer R.E.
        • Plantinga L.
        • Krisher J.
        • Pastan S.O.
        Dialysis facility and network factors associated with low kidney transplantation rates among United States dialysis facilities.
        Am J Transplant. 2014; 14: 1562-1572
        • King K.L.
        • Husain S.A.
        • Jin Z.
        • Brennan C.
        • Mohan S.
        Trends in disparities in preemptive kidney Transplantation in the United States.
        Clin J Am Soc Nephrol. 2019; 14: 1500-1511

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