The UNOS Scientific Renal Transplant Registry: multistep regression models on kidney graft survival.

1. Two-step Cox regression analyses showed that, for White recipients of first cadaver transplants, pretransplant transfusions, HLA-DR mismatch, donor race, CIT, size mismatch, PRA, old donor, and recipient age were significant prognostic factors during the first 6 months posttransplant, and after that, older donor, CIT, and size mismatch continued to have effects on graft survival in the longer term. 2. For African-American recipients of first cadaver transplants, pediatric donor, cause of donor death, and increasing second warm ischemia time were major risk factors in the early period, but in the late period, the effect of donor age dominated other factors. 3. Multistep linear logistic regression and two-step Cox regression analyses yielded similar results, with donor-related and histocompatibility factors dominating survival outcome in both the short and long terms.