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Kidney Week

Abstract: PO2101

When Is a Second Kidney Transplant Lifesaving? Effect of Waiting Time on Mortality in a Retrospective Cohort Study Using Target Trial Emulation

Session Information

Category: Transplantation

  • 1901 Transplantation: Basic


  • Kainz, Alexander, Medical University of Vienna, Department of Nephrology, Vienna, Austria
  • Kammer, Michael, Medical University of Vienna, Department of Nephrology, Vienna, Austria
  • Reindl-Schwaighofer, Roman, Medical University of Vienna, Department of Nephrology, Vienna, Austria
  • Strohmaier, Susanne, Medical University of Vienna, Department of Epidemiology, Vienna, Austria
  • Petr, Vojtech, Institut klinicke a experimentalni mediciny, Praha, Czechia
  • Viklicky, Ondrej, Institut klinicke a experimentalni mediciny, Praha, Czechia
  • Abramowicz, Daniel S., Antwerp University Hospital, Department of Nephrology, Antwerp, Belgium
  • Naik, Marcel, Charité Universitätsmedizin Berlin, Department of Nephrology and Medical Intensive Care, Berlin, Germany
  • Mayer, Gert J., Medizinische Universitat Innsbruck Universitatsklinik fur Innere Medizin IV Nephrologie und Hypertensiologie, Innsbruck, Austria
  • Oberbauer, Rainer, Medical University of Vienna, Department of Nephrology, Vienna, Austria

The median kidney transplant half-life is 10 to 15 years, and because of the scarcity of donor organs and immunological sensitization of candidates for retransplantation, there is a need for quantitative information if, and when a second transplantation is no longer associated with a reduced risk of mortality compared to waitlisted patients treated by dialysis. Therefore we investigated the association of time on waitlist with patient survival in patients who received a second transplantation versus remaining on waitlist with continued dialysis treatment.


In this retrospective study we used data of 2346 patients from the Austrian dialysis and transplant registry merged with data from Eurotransplant who were waitlisted for second kidney transplantation during the years 1980 to 2019. The analysis was based on target trial emulation via a sequential Cox approach, in which each observed transplant allocation started a virtual trial mimicking a randomized trial via inverse probability weighting. The analysis was adjusted for recipient age and sex, year and duration of first transplantation, duration of dialysis, and time between first graft loss and initial joining date of the waiting list for the second transplantation.


Second kidney transplantation showed an increased restricted mean survival time (RMST) at 10 years of follow-up compared to remaining on the waiting list (5.8 life-months gained, 95% CI 0.9 to 11.1). However, this survival benefit was diminished in patients with longer waiting time after first graft loss: RMST differences at 10 years of follow-up were 8.0 (95% CI 1.9 to 14.0) and 0.1 life-months gained (95% CI -14.3 to 15.2) for patients with a waiting time after first graft loss of less than one year, and eight years, respectively.


Based on these data we conclude that a second kidney transplant leads to prolonged patient survival compared to remaining waitlisted and treatment by dialysis, but that the survival benefit diminishes with longer waiting time. Nevertheless, the higher quality of life after transplantation could be an argument to favour retransplantation if a suitable donor organ is available.


  • Government Support – Non-U.S.