Impact of acute rejection episodes on long-term renal allograft survival

Objective To assess the impact of the number, and time of acute rejection (AR) and outcome of anti-rejection therapy on the long-term survival of renal allografts and the relative risk factors. Methods The Kaplan-Meier analysis and log-rank test were used to calculate the survival rates of patients and grafts in no acute rejection group (NAR, 895 patients), 1 rejection episode group (11 AR, 183), 2 and more than 2 rejection episodes group (2AR, 17), acute rejection group [AR (1AR + 2AR), 200], early acute rejection group (within 90 days after transplantation, EAR, 125), late acute rejection group (91 days later, LAR, 58) completely AR reversed group (CAR, 105), and incompletely AR reversed group (IAR, 68) The relative risk factors were analyzed by the Cox proportional hazards regression. Results The 5- and 10-year survival rates of renal allografts were 75.4% and 17.1% in AR and 93.2% and 86.5% in the NAR group (P < 0.0001). The long-term graft survival was much lower in the 2AR group than in the NAR or 1 AR groups (P < 0.0001 and P = 0.002, respectively). It was similar in either the NAR or CAR groups (P = 0.31), but it was significantly lower (P < 0.0001) in the IAR group. Multivariate Cox regression analysis revealed that the outcome of anti-rejection therapy is an important risk factor affecting the long-term survival of allografts. Conclusions AR is significantly associated with poor long-term survival of renal allografts. But the long-term graft survival of patients with one acute rejection but completely reversed is not significantly different from that of patients without acute rejection.