Increased rejection in living unrelated versus living related kidney transplants does not affect short-term function and survival

Background. At our institution, increased kidney donation from unrelated donors accounts for a steady rise in live donor kidney transplantation rates. We compared outcomes of living related (LRT) versus living unrelated kidney transplants (LURT) and analyzed the effect of early rejection upon graft survival. Methods. A retrospective analysis on 428 adult living donor kidney transplants was performed. Graft function and survival were compared between LRT and LURT and risk factors for 1-year rejection were defined by multivariate analysis. Results. Between 1/1/97 and 12/31/01, 308 LRT and 120 LURT were performed at the University of California San Francisco. Donor age and number of mismatches were significantly higher in the LURT group. Patient and graft survival were similar in both groups. After a median follow-up of 26 months, graft survival was 94.8% (LRT) versus 93.3% (LURT). Five-year serum creatinine levels were comparable in both populations. One-year rejection was higher in the LURT group (30% vs. 18.5%; P < 0.01). Rejection was influenced by the number of human leukocyte antigen mismatches. Other independent risk factors for early rejection were poor initial graft function, donor age greater than 55 years, and recipient body mass index greater than 30. Patients with poor initial graft function and early rejection had a statistically greater incidence of subtherapeutic tacrolimus trough levels on postoperative day 7. Conclusions. Despite a higher incidence of early rejection, LURT show similar function and survival compared with LRT. In high-risk patients receiving living unrelated renal transplants, consideration should be given to intensify initial immunosuppression to prevent early rejection episodes.