Trends in the timing of pre-emptive kidney transplantation.

Pre-emptive kidney transplantation is considered the best available renal replacement therapy, but no guidelines exist to direct its timing during CKD progression. We used a national cohort of 19,471 first-time pre-emptive kidney transplant recipients between 1995-2009 to evaluate patterns and implications of transplant timing. Mean estimated GFR (eGFR) at the time of pre-emptive transplant increased significantly over time, from 9.2 ml/min/1.73 m(2) in 1995 to 13.8 ml/min/1.73 m(2) in 2009 (P<0.001). Patients with eGFR ≥ 15 ml/min/1.73 m(2) represented an increasing proportion of pre-emptive transplant recipients, from 9% in 1995 to 35% in 2009; the trend for patients with eGFR ≥ 10 was similar (30% to 72%). We did not detect statistically significant differences in patient survival or death-censored graft survival between strata of eGFR at the time of transplant, either in the full cohort or in subgroup analyses of patients who might theoretically benefit from earlier pre-emptive transplantation. In summary, pre-emptive kidney transplantation is occurring at increasing levels of native kidney function. Earlier transplantation does not appear to associate with patient or graft survival, suggesting that earlier pre-emptive transplantation may subject donors and recipients to premature operative risk and waste the native kidney function of recipients.