Recipient-related predictors of kidney transplantation outcomes in the elderly.

Background: It is not clear whether in old people with end-stage renal disease kidney transplantation is superior to dialysis therapy.

Methods: We compared mortality rates between kidney transplant recipients (KTRs) and the general population across different age categories. We also examined patient and allograft survival in 15 667 elderly KTRs (65-<90 yr old, 36% female) within three age subgroups (65-<70, 70-<75, and ≥75 yr).

Results: The rise in the relative risk of death in older age groups was substantially less in KTRs than in the general population, that is, 1.8 and 2.0 vs. 21.4 and 76.6 in those aged 65-<75 and ≥75 yr, respectively, compared with 15- to <65-yr-old people (reference group). In 65- to <70-yr-old KTRs, obesity (BMI>30 kg/m(2) ) was associated with 19% higher risk of graft failure (HR: 1.19 [1.07-1.33], p = 0.002). Diabetes was a predictor of worse patient survival in all age groups but poorer allograft outcome in the youngest age group (65-<70 yr old) only. None of the examined risk factors affected allograft outcome in the oldest group (≥75 yr old) although there was a 49% lower trend of graft failure in very old Hispanic recipients (HR: 0.51 [0.26-1.01], p = 0.05).

Conclusions: Kidney transplantation may attenuate the age-associated increase in mortality, and its superior survival gain is most prominent in the oldest recipients (≥75 yr old). The potential protective effect of kidney transplantation on longevity in the elderly deserves further investigation.