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/1.73m² in 1995 to 13.8 ml/min/ 1.73m² in 2009 (P<0.001). Patients with eGFR≥15 ml/min/1.73m² 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 deathcensored 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.