The effect of age and prolonged cold ischemia times on the national allocation of cadaveric renal allografts

Background. National sharing of cadaveric renal allografts for perfectly ma tched kidneys (0 antigen mismatch) has improved outcome in the recipients o f these kidneys despite increasing cold storage times. However, there may b e limits to outcome improvement of matched kidneys based on age and cold st orage time. Materials and methods. To determine if national sharing of kidneys based on matching improves outcome regardless of donor age and cold storage time, w e evaluated the United Network for Organ Sharing (UNOS) Scientific Registry for all recipients of cadaveric kidney transplants between January 1, 1990 and July 31, 1998. We divided the recipients into four groups based on don or age and cold storage time. Group 1 comprised young donors (donor age <55 years) with average (<24 h) cold storage time; group 2, young donors with long (greater than or equal to 24 h) cold storage time; group 3, older dono rs (donor age greater than or equal to 55 years) with average cold storage time; and group 4, older donors with long cold storage time. Results. A total of 64,046 recipients were evaluated: 35,061 (55%) in group 1, 21,264 (33%) in group 2, 4308 (7%) in group 3, and 3414 (5%) in group 4 . Early graft performance progressively decreased from group 1 to group 4. Delayed graft function (DGF: dialysis requirement in the first 7 days postt ransplant) was 18, 29, 33, and 42% (P < 0.0001); serum creatinine at 3 year s (in mg/dl) was 1.70 +/- 0.8, 1.73 +/- 0.9, 2.31 +/- 1.0, and 2.42 +/- 1.1 (P < 0.0001); 1year graft survival was 87, 84, 79, and 77% (P < 0.0001); a nd 8-year graft survival was 77, 74, 63, and 62% (P < 0.0001, for groups 1 and 2 vs groups 3 and 4, respectively). The trends in DGF persisted through the groups in 0 antigen mismatched kidneys. Conclusions. Early function is adversely affected by prolonged cold storage , despite matching, in recipients of younger and older donor kidneys. Long- term function does not appear to be affected by prolonged cold storage. Rec ipients of kidneys from donors greater than or equal to 55 years of age hav e significantly worse short- and long-term outcome and may not benefit from national sharing. (C) 2000 Academic Press.