The UNOS Scientific Renal Transplant Registry

Abstract

Based upon data reported to the UNOS Scientific Renal Transplant Registry regarding transplants performed between 1994-1998, the one- and 3-year graft survival rates for 16,288 recipients of living donor kidneys were 93% and 86%, respectively, with a half-life of 17 years. Among those were 2,129 transplants from HLA-identical siblings with one- and 3-year graft survival rates of 96% and 93% and a 39-year half-life, 3,140 sibling donor grafts matched for one HLA haplotype with 94% and 87% one- and 3-year survival rates and a 16-year half-life and 2,071 transplants from living unrelated donors with 92% and 86% one- and 3-year graft survival rates and a 17-year half-life. The overall results of 35,289 cadaver donor kidney transplants were 87% and 76% graft survival at one- and 3-years with a 10-year half-life. There was a 13% difference in 3-year graft survival rates when recipients of kidneys from donors over or under age 55 were considered separately and the half-life was 11 years for younger donors and 6 years when the donor was older (p < 0.001). A total of 4,688 (14%) of cadaver kidney recipients received an HLA-matched transplant. Their graft survival rates were 89% and 83% at one and 3 years and their graft half-life was 16 years compared with 86% and 76% one- and 3-year graft survival and a 10-year half-life for recipients of HLA-mismatched kidneys (p < 0.001). The recipient's age affected both graft survival and the cause of graft loss. Recipients aged 19-45 had a 78% 3-year graft survival rate compared with 72% for recipients over age 60 or under 18 (p < 0.001). However, 65% of graft losses after the first year among older recipients were due to death with a functioning graft compared with 18% among 19-45-year olds. Acute rejections accounted for 16% of graft failures after the first year when the recipient was aged 6-18. Immune failures decreased with increasing recipient age. The recipient's race also influenced graft survival rates. Asian recipients of cadaver kidneys had the highest graft survival rates of 91% and 85% at one and 3 years with a half-life of 18 years. The result for Whites and Blacks were significantly lower (87-86% at one year and 78% and 70% at 3 years, respectively; p < 0.001). The graft half-life was 12 years for Whites and 7 years for Blacks. DGF and acute rejection episodes during the early posttransplant period reduced 3-year survival of cadaveric transplants by 20% and reduced graft half-lives by 2 years (rejections) or 4 years (DGF). When rejections occurred in recipients with DGF, 3-year graft survival was 64%. Induction therapy with anti-T-cell reagents did not affect graft survival rates among patients with DGF, but reduced the incidence of early rejections from 27-14%. Rejections that occurred within the first 6 months had a more pronounced effect on subsequent graft half-lives (11.6 years without and 7.6 years with; p < 0.01) and increased the proportion of kidneys that failed because of chronic rejection from 31-43% between 1-3 years. More than 50% of diabetics received a simultaneous pancreas kidney transplant during this period and the graft and patient survival rates were significantly higher for recipients of the SPK transplants. When deaths with a functioning graft were censored, however, the graft failure rates were not significantly different. The major causes of death among cadaver kidney transplant recipients were cardiovascular (26%) and infections (24%) during the first posttransplant year. Between 1-3 years, the percentage of deaths due to infection fell to 15% and malignancies accounted for 13% of patient deaths.