Faculty Bibliography

The Kidney Allocation System (KAS), a major change to deceased donor kidney allocation, was implemented in December 2014. Goals of KAS included directing the highest-quality organs to younger/healthier recipients and increasing access to deceased donor kidney transplantation (DDKT) for highly sensitized patients and racial/ethnic minorities. Using national registry data, we compared kidney distribution, DDKT rates for waitlist registrants, and recipient characteristics between January 1, 2013, and December 3, 2014 (pre-KAS) with those between December 4, 2014, and August 31, 2015 (post-KAS). Regional imports increased from 8.8% pre-KAS to 12.5% post-KAS; national imports increased from 12.7% pre-KAS to 19.1% post-KAS (P<0.001). The proportion of recipients >30 years older than their donor decreased from 19.4% to 15.0% (P<0.001). The proportion of recipients with calculated panel-reactive antibody =100 increased from 1.0% to 10.3% (P<0.001). Overall DDKT rate did not change as modeled using exponential regression adjusting for candidate characteristics (P=0.07). However, DDKT rate (incidence rate ratio, 95% confidence interval) increased for black (1.19; 1.13 to 1.25) and Hispanic (1.13; 1.05 to 1.20) candidates and for candidates aged 18-40 (1.47; 1.38 to 1.57), but declined for candidates aged >50 (0.93; 0.87 to 0.98 for aged 51-60 and 0.90; 0.85 to 0.96 for aged >70). Delayed graft function in transplant recipients increased from 24.8% pre-KAS to 29.9% post-KAS (P<0.001). Thus, in the first 9 months under KAS, access to DDKT improved for minorities, younger candidates, and highly sensitized patients, but declined for older candidates. Delayed graft function increased substantially, possibly suggesting poorer long-term outcomes.

BACKGROUND:Evaluation of candidates to serve as living kidney donors relies on screening for individual risk factors for end-stage renal disease (ESRD). To support an empirical approach to donor selection, we developed a tool that simultaneously incorporates multiple health characteristics to estimate a person's probable long-term risk of ESRD if that person does not donate a kidney. METHODS:We used risk associations from a meta-analysis of seven general population cohorts, calibrated to the population-level incidence of ESRD and mortality in the United States, to project the estimated long-term incidence of ESRD among persons who do not donate a kidney, according to 10 demographic and health characteristics. We then compared 15-year projections with the observed risk among 52,998 living kidney donors in the United States. RESULTS:A total of 4,933,314 participants from seven cohorts were followed for a median of 4 to 16 years. For a 40-year-old person with health characteristics that were similar to those of age-matched kidney donors, the 15-year projections of the risk of ESRD in the absence of donation varied according to race and sex; the risk was 0.24% among black men, 0.15% among black women, 0.06% among white men, and 0.04% among white women. Risk projections were higher in the presence of a lower estimated glomerular filtration rate, higher albuminuria, hypertension, current or former smoking, diabetes, and obesity. In the model-based lifetime projections, the risk of ESRD was highest among persons in the youngest age group, particularly among young blacks. The 15-year observed risks after donation among kidney donors in the United States were 3.5 to 5.3 times as high as the projected risks in the absence of donation. CONCLUSIONS:Multiple demographic and health characteristics may be used together to estimate the projected long-term risk of ESRD among living kidney-donor candidates and to inform acceptance criteria for kidney donors. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).