Post Kidney Transplant Hospitalizations and Long-term Outcomes: A Prospective Multi-Center Study.

Abstract

Background: AKI is associated with an increased risk of CKD and ESKD. However, only limited studies have investigated the impact of AKI episodes on kidney transplant outcomes. This study evaluated the impact of rehospitalization associated with non-immunological AKI on long-term outcomes. Data on rehospitalization with AKI after kidney transplant is not reported to UNOS and thus, there are no large datasets available to study this association.

Methods: We completed chart reviews of 989 deceased donor kidney transplant recipients transplanted from 2010-2014 at 13 transplant centers in the Deceased Donor Study Consortium. Rehospitalizations up to 5 years post-transplant were included. The cause of rehospitalizations was adjudicated by a transplant nephrologist based on the discharge diagnosis. Primary outcomes were the impact of AKI-related rehospitalization on death-censored graft failure and all-cause mortality. We excluded rehospitalizations due to acute rejection from the primary analysis. The cohort was linked to data from OPTN supplied by UNOS. Time-varying cox-proportional hazard models were used to examine the association between rehospitalization and outcomes.

Results: We identified 200(20%) recipients with at least one rehospitalization associated with AKI, 516 (52%) with rehospitalizations without AKI and 273 (28%) without a rehospitalization post-transplant. Delayed graft function, donor age and KDPI score differed between the three groups. We found a higher risk of death censored graft failure aHR 7.5 (CI 4.0-13.8), all-cause graft failure aHR 6.7 (CI 4.2-10.8) and all-cause mortality aHR 5.7 (CI 2.7-11.8) for rehospitalizations associated with AKI compared to no rehospitalization. The non-AKI rehospitalizations also had significantly higher rates of measured outcomes however, the associations were not as strong.

Conclusions: AKI rehospitalizations were associated with a significantly increased risk of poorer graft outcomes and thus closer follow-up of this high-risk group is warranted.