A multi-factor analysis of kidney graft outcomes at one and five years posttransplantation: 1996 UNOS Update

1. GENERAL: Here we updated our analysis of the UNOS Kidney Registry for the compound effects of 26 transplantation factors on graft survival within 2 consecutive posttransplantation risk periods. During the early risk period, 83,867 kidney-only recipients were followed through one year, and, in the second (chronic) risk period, 66,358 recipients whose grafts survived beyond one year were followed for 5 years after transplantation. 2. SHORT-TERM EFFECTS: From the analysis, the top (< 2% of assignable variation) factors influencing one-year graft survival rates were ranked as follows: 1) living-related and living-unrelated donor transplants were preferred; 2) some transplant centers had outstanding results; 3) kidneys from stroke victims displayed poor results; 4) recipients with PRA > 80% demonstrated poor survival; 5) patients transplanted before 1991 had poor results; 6) increasing numbers of HLA-ABDR mismatches decreased survival; 7) cold ischemia times beyond 24 hours diminished survival; 8) kidneys from younger and older donors impaired survival; 9) regrafting was detrimental, 10) Asians and Hispanics enjoyed superior results; 11) recipients with restricted activities pretransplantation were at higher risk of early graft failure; and 12) high (> 30 kg/m2) body mass recipients demonstrated lowered rates. 3. LONG-TERM EFFECTS: Fewer net factors influenced graft survival beyond 1 year through 5 years. The following 9 factors, each explaining > 2% of the assignable variation in conditional 5-year graft survival, were ranked and yielded poor results: 1) older (> 65) donors; 2) Black recipients; 3) poor transplant centers; 4) male recipients; 5) kidneys from cadaver or living parental donors; 6) transplantation prior to 1991; 7) stroke donors; 8) non-zero HLA-AB mismatched transplants; and 9) teenage recipients. 4. IMPACT ON KIDNEY ALLOCATION: This UNOS data analysis combined with other recent multi-center studies suggest that the criteria for kidney allocation need contain just 2 components in order to maximize long-term survival-an immunologic factor (avoiding HLA mismatches) and a non-immunologic factor (a senior citizens pool to receive older donor organs).