Racial/ethnic disparities in waitlisting for deceased donor kidney transplantation 1 year after implementation of the new national kidney allocation system

Abstract

The impact of a new national kidney allocation system (KAS) on access to the national deceased-donor waiting list (waitlisting) and racial/ethnic disparities in waitlisting among US end-stage renal disease (ESRD) patients is unknown. We examined waitlisting pre- and post-KAS among incident (N = 1 253 100) and prevalent (N = 1 556 954) ESRD patients from the United States Renal Data System database (2005-2015) using multivariable time-dependent Cox and interrupted time-series models. The adjusted waitlisting rate among incident patients was 9% lower post-KAS (hazard ratio [HR]: 0.91; 95% confidence interval [CI], 0.90-0.93), although preemptive waitlisting increased from 30.2% to 35.1% (P < .0001). The waitlisting decrease is largely due to a decline in inactively waitlisted patients. Pre-KAS, blacks had a 19% lower waitlisting rate vs whites (HR: 0.81; 95% CI, 0.80-0.82); following KAS, disparity declined to 12% (HR: 0.88; 95% CI, 0.85-0.90). In adjusted time-series analyses of prevalent patients, waitlisting rates declined by 3.45/10 000 per month post-KAS (P < .001), resulting in ≈146 fewer waitlisting events/month. Shorter dialysis vintage was associated with greater decreases in waitlisting post-KAS (P < .001). Racial disparity reduction was due in part to a steeper decline in inactive waitlisting among minorities and a greater proportion of actively waitlisted minority patients. Waitlisting and racial disparity in waitlisting declined post-KAS; however, disparity remains.

Keywords: epidemiology; ethics and public policy; ethnicity/race; health services and outcomes research; kidney transplantation/nephrology; organ allocation; organ procurement and allocation; quality of care/care delivery.

Figure 1. Definition of the incident and prevalent U.S. ESRD patient populations used for study aims, 2005–2015

Abbreviations: ESRD, End stage renal disease; KAS, kidney allocation system Note: The waitlisting date for preemptive waitlisting patients was considered as the dialysis starting date for both incident and prevalent ESRD patients.

Figure 2. Monthly rate of new waitlisting events per 10,000 prevalent dialysis patients in the U.S. from 2005 to 2015

Note: The vertical line indicates the introduction of the new Kidney Allocation System on December 4, 2014

Figure 3. Change in adjusted rate of waitlisting among prevalent ESRD patients in the United States post-KAS (vs pre-KAS) by patient time on dialysis, derived from interrupted time series models, 2011–2015

Abbreviations: ESRD, End stage renal disease; KAS, kidney allocation system Note: The interrupted time series regression model adjusted for time trends. The coefficient represented in the Y axis represents the estimated change in waitlisting rate associated with KAS, after adjusting for time trends. Negative coefficients indicate declines in waitlisting. Patients who were waitlisted prior to dialysis start were excluded from these analyses. P-values for trend test for the association of change in rate of waitlisting by dialysis vintage is as follows: all patients (p<0.0001); white (p=0.058); black (p=0.011); Hispanic (p=0.002); and Asian (p=0.052).

Figure 4. Monthly time series of the count of new active waitlisting events by racial/ethnic groups from United Network for Organ Sharing Data, 2005 to 2015

Note: The vertical line indicates the introduction of the new Kidney Allocation System on December 4, 2014.

Figure 5. Monthly time series of the count of new inactive waitlisting events by racial/ethnic groups from United Network for Organ Sharing Data, 2005 to 2015

Note: The vertical line indicates the introduction of the new Kidney Allocation System on December 4, 2014.