Influence of time of rejection on long-term graft survival in renal transplantation.

Background: The aim of this analysis was to investigate the relationship of acute rejection episodes (ARE) at different times posttransplantation with reversibility of graft dysfunction and long-term graft failure using data from the Collaborative Transplant Study database.
Methods: A total of 28,867 patients receiving their graft between 1995 and 2005 from deceased donors were included in the analysis. The time from renal transplantation to first treated ARE was divided into intervals up to 3 years. Long-term graft survival and half-life rates were calculated and hazard ratios (HR) for failure were computed using multivariate Cox regression analysis.
Results: Compared with patients who did not receive rejection treatment during the first posttransplant year, HR for graft survival increased to 1.35 for patients with rejection 0 to 90 days (P<0.001), 2.05 with rejection 91 to 180 days (P<0.001), and 2.74 with rejection 181 to 365 days of posttransplantion (P<0.001). First rejections occurring during the second year were associated with HR 3.35 (P<0.001) and rejections during the third year with HR 3.17 (P<0.001). In addition to the time of rejection, the degree of functional recovery after rejection treatment was found to be important for subsequent graft survival.
Conclusion: The time point of occurrence and the degree of functional recovery after rejection treatment were found to significantly influence the impact of ARE on long-term graft survival, and we were able to quantify the associated risks.