Compound Effect of Kidney Donor Profile Index and Cold Ischemic Time on 1-Year Kidney Transplant Recipient Outcomes

Objective. Kidney Donor Profile Index (KDPI) and cold ischemic time (CIT) independently influence recipient outcomes after kidney transplantation; however, the compound effect of these variables on posttransplant outcomes is unknown. Design. The Scientific Registry of Transplant Recipients database of deceased-donor kidney transplant recipients between January 2012 and December 2016 was reviewed. Recipients were stratified based on their KDPI (0%-20%, 21%-85%, 86%-100%) and then based on CIT (0-12, 13-24, 25-30, 31-36, > 37 hours). The primary outcome is 1-year allograft loss. Secondary outcomes include primary nonfunction, delayed graft function, biopsy-proven rejection, and 1-year recipient mortality. Results. Allograft loss was not affected by CIT for KDPI 0% to 20% (P =.898) or KDPI 86% to 100% (P =.731), but was significantly different for KDPI 21% to 85% (P <.001). The KDPI 21% to 85% group was the only group with a significant difference in primary nonfunction, demonstrating a linear rise with increasing CIT (P <.001). CIT did not affect recipient mortality for any KDPI group (KDPI 0%-20%, P =.306; KDPI 21%-85%, P =.098; KDPI 86%400%, P =.774). Incidence of delayed graft function was greater for each KDPI group (P <.001) with increased CIT. Biopsy-proven rejection was not affected by CIT for KDPI 21% to 85% (P =.244) or KDPI 86% to 100% (P =.946). For KDPI 0% to 20%, there was a significant difference (P =.024); however, the incidence was not linear with increasing CIT. For the KDPI 86% to 100% group, incidence of mortality, allograft loss, primary nonfunction, and biopsy-proven rejection did not differ between CIT groups. Conclusions. Extended CIT alone should not hinder utilization of higher KDPI organs.