title: Explainable variation in renal transplant outcomes: a comparison of standard and expanded criteria donors.
abstract: In 2002, OPTN/UNOS altered kidney allocation rules to allow patients to be listed separately to receive kidneys from expanded criteria donors (ECD). Our aim was to quantify the short- and long-term impacts of 21 prognostic factors on recipients of ECD as well as recipients of living (LD) and deceased standard criteria (SCD) donors. A factor's impact depends on both the risk and diversity of its effects. Using OPTN/UNOS Registry data from 1996-2003, we have analyzed kidney-only, adult-recipient grafts for factor effects among 35,878 LD, 47,941 SCD and 10,399 ECD transplants. During an early risk period, all 94,218 recipients were followed through one year, and, in the late risk period, 85,270 recipients whose grafts survived beyond one year were followed for 5 years post-transplant. Impact was measured by determining a factor's percentage of assignable variation in one- and 5-year graft failure rates. Scores for 21 factors were estimated via generalized logistic models, which contained a random component for transplant center. The assignable variation associated with a given factor was computed as the factor score variance multiplied by the square of the corresponding regression coefficient. Impacts were heterogeneous with regard to posttransplant period and donor type. The top 5 factors influencing one-year graft survival rates were as follows: * For LD grafts - pretransplant dialysis time (14% of the variation in short-term outcomes), recipient age (13%), body mass (12%), PRA (10%) and induction therapy (10%). * For SCD grafts - donor age (24%), recipient age (12%), pretransplant dialysis time (12%), HLA-DR matching (6%) and pretransplant medical condition (6%). * For ECD grafts - donor age (18%), pre-transplant dialysis time (10%), recipient age (10%), pretransplant medical condition (10%) and recipient body mass (6%). Ranking long-term outcomes demonstrated the following top 5 influential factors: * For LD grafts - donor age (28% of the variation in long-term outcomes), recipient race (15%), age (15%), transplant year (13%) and recipient sex (11%). * For SCD grafts - donor age (35%), recipient race (23%), transplant year(15%), recipient sex (8%)and age (5%). * For ECD grafts - donor age (33%), recipient sex (20%), race (15%), transplant year (8%) and recipient's original disease (5%). Donor age was the dominant factor governing the survival rates among deceased donor kidney transplants. Advancing donor age was still the major risk factor for SCD transplant failure despite setting aside all donors 60 and up, and a large fraction of 50-59 year-old donors, from this group. Current ECD/SCD definitions warrant review and possible revision.
authors.affiliation: UCLA Immunogenetics Center, Los Angeles, California, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Gjertson
mesh_terms: D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D016030:Kidney Transplantation / Q000401:mortality / Q000706:statistics & numerical data; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012042:Registries; D015996:Survival Rate; D013997:Time Factors; D014019:Tissue Donors; D009927:Tissue and Organ Procurement / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology