Dialysis prior to living donor kidney transplantation and rates of acute rejection

Background. The relationship between transplantation prior to chronic dialysis initiation and the pattern of acute rejection of kidneys from living donors (LDKT) has not been fully explored. Methods. Using data provided by the United States Renal Data System, we performed a retrospective cohort study fitting multivariate proportional hazards models to characterize the association of chronic use of dialysis prior to transplantation [non-pre-emptive LDKT (non-PLDKT)] and acute rejection, and to examine if this association varies throughout the first year. Results. Non-PLDKT was associated with a 2.5-fold higher rate of biopsy-confirmed rejection during the first month [adjusted HR 2.5, 95% confidence interval (1.85-3.33)], compared with no dialysis prior to transplantation. Increasing duration of pre-transplant dialysis was associated with increasing rate of biopsy-confirmed acute rejection during the first month (P = 0.001 for trend). Over the first year, there was a diminishing relationship between non-PLDKT and acute rejection: 2.5-, 2.22-, 2.13- and 1.78-fold elevation in the episodes of biopsy-confirmed acute rejection during the first, second, third through to the sixth and seventh through to the twelfth month post-transplant, respectively (P = 0.05 for trend). Conclusions. The waning of the association of non-PLDKT with acute rejection over time supports the hypothesis that dialysis exposure prior to transplantation may modulate the immune system to increase the rates of acute rejection.