Sex and age effects in renal transplantation.

1. The age and sex of the recipient were not significant factors in transplant outcome. The age and sex effects observed were all associated with the kidney donor. 2. The 1-year graft survival rates for male and female donor kidneys were 78% and 76%, respectively in first cadaver transplants and 91% and 88%, respectively, in parent donor first transplants. The donor sex had no significant effect on survival of transplants from sibling donors, irrespective of HLA match. 3. Long-term survival rates, reflected in transplant half-lives, were also significantly better in recipients of male cadaver (8 years) or paternal donor (13 years) first transplants than in recipients of female cadaver (6 years) or maternal donor (9 years) kidneys. 4. A higher percentage of HLA-A,B matched cadaver kidneys than mismatched organs were transplanted to sensitized recipients. Despite a higher percentage of sensitized female recipients, there was no difference in first cadaver transplant survival comparing males and females. 5. A positive flow cytometry crossmatch (FCXM) was associated with poor 3-month cadaver retransplant survival in both males (54%) and females (56%) compared with 83% and 76%, respectively, for FCXM-negative males and females. 6. The impact of preformed antibodies on first cadaver transplant outcome differed between males and females. Among sensitized recipients, females had 83% and 81% 3-month graft survival with a positive and negative FCXM, respectively, whereas positive FCXM male patients had 71% vs 86% for FCXM-negative males. 7. Graft survival ranged from 76%-79% in first transplant recipients aged 1-5, 6-14, 15-55, and over 55 when the cadaver donor age was 15-55. Poorer survival rates in pediatric and older recipients were associated with "age-matching" the donor kidney. Nearly 40% of pediatric patients received kidneys from pediatric donors that did poorly in all recipient age groups. More than 20% of kidneys from donors over 55 were transplanted to older recipients. These older donor kidneys also had uniformly poor survival in all recipient age groups. 8. When death was excluded as a cause of graft loss in first cadaver transplants, patients over 55 had an 80% 1-year graft survival rate. Although death was clearly a factor for older patients, it was interesting that survival including death was 76% when the donor age was 15-55 and 63% when the donor was over 55.