Risk factors and outcome of expanded-criteria donor kidney transplants in patients with low immunological risk.

QUESTIONS UNDER STUDY The aim of this study was to evaluate risk factors and outcome of expanded-criteria donor (ECD) kidney transplants in patients with low immunological risk. METHODS We evaluated graft survival and graft function in 265 recipients with low immunological risk defined as the absence of pretransplant donor-specific HLA antibodies. RESULTS A total of 112 (42%) kidneys derived from ECD and 153 (58%) from standard-criteria donors (SCDs). Overall, in a multivariate Cox regression, ECD status was the only significant risk factor for graft failure (hazard ratio [HR] 2.31, 95% confidence interval [CI] 1.22-4.37; p = 0.01). In the SCD group there was an increased risk for graft failure with increasing recipient age (HR 1.06 per year, CI 1.01-1.10; p = 0.02) and in the ECD group a trend for risk reduction for recipients treated with tacrolimus (Tac) (HR 0.46, CI 0.20‒1.06; p = 0.07). One, three and five-year graft survival of ECD kidneys was significantly better when recipients were treated with Tac (95%, 88% and 72%, respectively) than when they were treated without Tac (73%, 65% and 50%, respectively) (p = 0.008). At three years, ECD kidneys had a lower median estimated creatinine clearance (eCrCl) than SCD kidneys (37 vs 58 ml/min, p <0.001). Within the ECD group, recipients treated with Tac had a higher median eCrCl than those treated without Tac (41 ml/min vs 33 ml/min, p = 0.004). Graft function from one to three years was preserved in ECD recipients treated with Tac (median change 0.0 ml/min, p = 0.4) compared with those treated without Tac (median change -3.2 ml/min, p = 0.005). CONCLUSION Tac-based immunosuppression seems to improve graft survival and to preserve graft function in ECD kidneys with low immunological risk.