Pre-transplant maintenance dialysis duration and outcomes after kidney transplantation: a multicenter population-based cohort study

The association between pre-transplant dialysis duration and post-transplant outcomes may vary by the population and endpoints studied. We conducted a population-based cohort study using linked healthcare databases from Ontario, Canada including kidney transplant recipients (n = 4461) from 2004–2014. Our primary outcome was total graft failure (i.e., death, return to dialysis, or pre-emptive re-transplant). Secondary outcomes included death-censored graft failure, death with graft function, mortality, hospitalization for cardiovascular events, hospitalization for infection, and hospital readmission. We presented results by pre-transplant dialysis duration (pre-emptive transplant, and 0.01-1.43, 1.44-2.64, 2.65-4.25, 4.26-6.45, and 6.46-36.5 years, for quintiles 1–5). After adjusting for clinical characteristics, pre-emptive transplantation was associated with a lower rate of total graft failure (adjusted hazard ratio [aHR] 0.68, 95% CI: 0.46, 0.99), while quintile 4 was associated with a higher rate (aHR 1.31, 95% CI: 1.01, 1.71), when compared to quintile 1. There was no significant relationship between dialysis duration and death-censored graft failure, cardiovascular events, or hospital readmission. For death with graft function and mortality, quintiles 3–5 had a significantly higher aHR compared to quintile 1, while for infection, quintiles 2–5 had a higher aHR. Longer time on dialysis was associated with an increased rate of several adverse post-transplant outcomes.