16.20 Consequences of Turning Down High KDPI Kidney Organ Offers for Kidney Transplant Candidates

J. D. Motter¹, L. Liyanage¹, K. R. Jackson¹, M. G. Bowring¹, T. Ishaque¹, Y. Yu¹, S. Yu¹, J. M. Garonzik-Wang¹, A. B. Massie^1,2, D. L. Segev^{1,2,3  1}Johns Hopkins University School Of Medicine,Baltimore, MD, USA ²Johns Hopkins Bloomberg School of Public Health,Baltimore, MD, USA ³Scientific Registry of Transplant Recipients,Minneapolis, MN, USA

Introduction:  Deceased-donor kidneys are scored according to a Kidney Donor Profile Index (KDPI) representing a percentile score of donor quality (e.g. KDPI=80 indicates lower expected graft survival than for 80% of other deceased-donor kidneys). The KDPI is used to determine organ allocation priority and guide patient/provider decision-making. Kidneys with KDPI≥80 ("high-KDPI kidney") are frequently declined due to increased risk of graft loss; however, candidates that decline must wait for a future offer that may never come. We sought to understand what happened to candidates who declined a high-KDPI kidney, and compare their survival to candidates who accepted.

Methods:  We used national data from SRTR between 2009-2018 to study 148,252 candidates who were offered a high-KDPI kidney. We used competing risks regression to characterize the natural history of those who declined, and then used weighted Cox regression to compare the post-decision survival of candidates who declined versus accepted high KDPI offers (i.e. what would have happened if candidates who declined had instead accepted). We used an interaction term to determine whether the survival benefit of acceptance varied across KDPI.

Results: Among candidates who declined high-KDPI kidneys, 41.9% were eventually transplanted, 25.3% died, and 31.0% were removed from the waitlist before receiving a transplant. Despite this substantial mortality risk, the survival benefit of acceptance depended on the KDPI range of the accepted kidney. Candidates who had accepted KDPI 80-95% kidneys experienced a 22% survival benefit compared to those who declined (weighted Hazard Ratio [wHR] for KDPI 80-95%: _0.740.78_0.82, p<0.001) (Figure 1A). Despite this, there was no statistically significant interaction between KDPI 80-95%, indicating that the survival benefit was the same between KDPI 80-95%. Conversely, candidates who accepted KDPI 96-100% kidneys had equivalent mortality risk compared to decliners (wHR: _0.850.94_1.08, p=0.5, absolute 5-year mortality risk 25.8% vs 28.5%) (Figure 1B).

Conclusion: Although candidates who accepted kidneys with a KDPI 80-95% derived a survival benefit, candidates who accepted KDPI 96-100% kidneys did not. Selection of KDPI 80-95% kidneys may reduce wait-times and improve survival.