Kidney Transplantation in the United States.
Clinical Transplants 2008, Chapter 1
This chapter summarizes data on 159,119 deceased donor (DD) and 83,471 living donor (LD) kidney transplants reported to the OPTN/ UNOS registry during the 20-year period between 1988 and 2007. The 15-year graft survival rates for transplants performed during 1991-1995 were 25% for 32,327 DD and 40% for 13,992 LD recipients. Graft survival rates improved modestly (4% for DD and 2% for LD) transplants performed during 1996-2005. Graft half-lives rose from 8 to 10 years for DD and from 12 to 18 years for LD transplant recipients during the study period. The number of DD kidney recipients over age 50 increased from 1,620 in 1988 to 4,492 in 2007 with no corresponding increase in the number of younger transplants. Annual LD kidney transplants increased from 1,816 in 1988 to 6,273 in 2004, but the rapid growth in LD transplants leveled off in 2001-2002 and may be falling in more recent years. The growth and slowdown of LD transplants occurred at different times for different groups of LD according to their relationship to the patient. Parent donor transplants have not increased substantially, whereas offspring-to-parent graft, spouse and sibling transplants increased rapidly in the early to mid-1990's donors and leveled off in 2001-2002. Other unrelated LD transplants began to rise in 1995 and continued to increase until 2005. Parent-to-child transplants have declined 33% since the new UNOS prioritization of pediatric recipients for young adult DD kidneys in 005. The difference in 10-year DD kidney survival between the best and worst HLA-matched combinations was 10%, with halflives ranging from 11.6 years to 8.6 years. Nearly one-third of DD transplants performed during 1996-2005 were completely HLA mismatched (5-6 HLA-A,B,DR mismatches) compared with 15% of transplants with no HLA antigens mismatched. About 11% of LD transplants were HLA-matched (most HLA-identical siblings) and 10-year graft survival was 74% compared with 58% for HLA mismatched transplants. There was no survival difference associated with increasing HLA mismatches among LD kidney recipients. The graft half-lives were 27 years for HLA-matched and 15 years for HLA-mismatched LD transplants The increasing use of newer solid-phase tests for HLA-antibodies appears to have inflated recent PRA estimates for sensitized patients as suggested by the increasing percentage of highly sensitized (80% PRA) patients transplanted since 2003 (from 25 to 40% of retransplanted patients). Three-year graft survival rates for broadly sensitized recipients during 2004-2007 was 77% (vs 79% for less sensitized) compared with 74% (vs 80% for less sensitized) during 1999-2003, which was more similar to the less sensitized patients in either period. There was considerable variability among centers in the percentage of broadly sensitized patients that were transplanted during each period, but most centers reported transplanting more sensitized patients between 2004-2007. Cold ischemia times (CIT) for DD kidney transplants have been reduced over the past 20 years from an average of 24 hours during 1988-1992 to 18 hours in 2003-2007. Despite this reduction in CIT, the incidence of delayed graft function has remained at 25% each year since 1990. The effect of prolonged CIT (> 30 hours) on graft survival was a 1% reduction over 10 years for DD kidneys under age 35 and a 4% reduction for DD kidneys over age 55 compared with the graft survival results for DD kidneys in either age group transplanted within 18 hours.