Predicting Long-term Outcomes in Deceased Donor Kidney Transplant Recipients Using Three Short-term Graft Characteristics.

Abstract

Delayed graft function (DGF) in kidney transplant recipients is used to determine graft prognosis, make organ utilization decisions, and as an important end-point in clinical trials. However, DGF is not an ideal measure of graft function. We aimed to develop and validate a model that provides incremental risk assessment for inferior patient and graft outcomes. We included adult kidney-only deceased donor transplant recipients from 1996 to 2016. In addition to DGF, two short-term measures were used to assess risk: renal function recovery<100% (attaining half the donor's eGFR) and recipient's 90-day eGFR<30. Recipients were at no-, low-, moderate- or high-risk if they met zero, one, two, or all criteria, respectively. Cox proportional hazards models were used to assess the independent relationship between the exposure and death-censored graft failure (DCGF) and mortality. Of the 792 eligible recipients, 24.5% experienced DGF, 40.5% had renal function recovery<100% and 6.9% had eGFR<30. Over a median follow-up of 7.3 years, the rate of DCGF was 18.7% and mortality was 25.1%. When compared with recipients at no risk, those at low-, moderate- and high-risk were noted to have an incremental increase in risk of DCGF (aHR=1.53, 95%CI:1.03-2.27; aHR=2.84, 95%CI:1.68-4.79; aHR=15.46, 95%CI:8.04-29.71) and mortality (aHR=1.16, 95%CI:0.84-1.58; aHR=1.85, 95%CI:1.13-3.07; aHR=2.66 (95%CI:1.19-5.97). When using a hierarchical approach, each additional exposure predicted the risk of DCGF better than DGF alone and 100 random bootstrap replications supported the internal validity of the risk model. In an external validation cohort deemed to be at lower risk for DCGF, similar non-significant trends were noted. We propose a risk model that provides an incremental assessment of recipients at higher risk of adverse long-term outcomes than DGF alone. This can help advance the field of risk assessment in transplantation and inform therapeutic decision-making in patients at the highest spectrum of inferior outcomes.