The race effect.

1. One-year graft survival rates were 93% for recipients of HLA-identical sibling transplants in Blacks and Caucasians. One-year graft survival rates were lower in Blacks than Caucasians by 6% for parent donor, 8% for first cadaver, and 4% for cadaver donor retransplants between 1984 and 1989. 2. Although 1-year graft survival was consistently lower in Black recipients, there was no significant race difference when the recipient was over age 45 years. In transplants performed after 1986, there was no significant race difference when the recipient was over age 30 years. 3. Black recipients aged 15-30 years had the poorest 1-year graft survival at 64% each year between 1984 and 1988. One-year graft survival in comparable Caucasian recipients improved from 73-82% during this interval. The difference was greatest (18%) when comparing young Black and Caucasian males. 4. Caucasians had better early function than Blacks as judged from serum creatinine levels in the first 60 days. Fifty-two percent of Caucasians had excellent function (SCr less than 1.5 mg/dl) vs 37% of Blacks. Conversely, 22% of Blacks had SCr levels that never fell below 2.5 mg/dl vs 16% of Caucasians. There was no racial difference in early graft survival when transplants were stratified by function. The race effect became apparent after 6-12 months. 5. Long-term graft survival continues to differ dramatically between Black and Caucasian recipients. Transplant half-lives were consistently 4 years among Black and 7.5 years among Caucasian recipients of first cadaver transplants. Even comparing HLA-identical sibling transplants, the late loss rate in Blacks was double that in Caucasians. 6. The transplant center was an important factor in the race effect. Blacks transplanted at centers with overall high success rates had 79% 1-year graft survival, not significantly lower than that of Caucasian recipients. As the overall success rates declined at good and fair centers, the difference in 1-year graft survival between Black and Caucasian recipients increased from 8% to 12%. 7. The transplant center did not influence long-term graft survival in Black recipients. Transplant half-lives ranged from 4.9-3.9 years at excellent and fair centers, respectively. 8. The difference in graft survival between Caucasian and Black donors was primarily a center effect. In transplants to Caucasian recipients, there was no difference between Caucasian and Black donors at excellent and good centers, and a 16% difference at fair centers.