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Survival Benefit of Kidney Transplantation Compared to Long-Term Dialysis Across Ages: A Retrospective Cohort Study Using Target Trial Emulation
20 Pages Posted: 22 Dec 2021
More...Abstract
Background: Kidney transplantation is considered beneficial in terms of survival over remaining on dialysis for patients with end-stage renal disease. However, randomized controlled trials are infeasible and available evidence form cohort studies is at high risk of bias. By applying causal inference methodology, we compared restricted mean survival times (RMSTs) between transplanted patients and patients remaining on dialysis across ages and depending on waiting time.
Methods: For this retrospective cohort study, we considered patients waitlisted for their first kidney transplant between 2000 and 2018 in Austria. Data from the Austrian Dialysis and Transplant Registry and from Eurotransplant included repeated updates on their waitlisting status and relevant covariates. To estimate causal effects of interest, we developed a target trial protocol and applied sequential Cox regression taking into account time-varying covariates and temporary withdrawal from waitlist.
Findings: We included 4 445 patients (33% female) with a mean age of 52 years, of which 3 621 patients were transplanted and 1 392 died. Within a 10-year follow-up transplantation showed a gain in average survival time across all considered ages compared to remaining on waitlist. The estimated RMST differences were 0·89 years (95% CI -0·05–1·95) at age 20, 3·06 (95% CI 2·67–3·53) at age 60, and 2·59 (95% CI 2·08–3·12) at age 70. The survival benefit for transplanted patients across all considered ages was independent of time spent on waiting list.
Interpretation: Kidney transplantation prolongs the survival time of persons with end-stage renal disease across all candidate ages and times spent on waiting list.
Funding Information: The study was supported by funds of the Oesterreichische Nationalbank (Austrian Central Bank, Anniversary Fund, project number: 17839). S. Strohmaier received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 795292.
Declaration of Interests: All authors declare no competing interests.
Ethics Approval Statement: The study was approved by the Ethics Committee of the Medical University Vienna (1788/2017), performed in accordance with the Declaration of Helsinki, and reported in accordance with the STROBE statement.
Keywords: kidney transplantation, dialysis, causal inference, target trial emulation, restricted mean survival times
Suggested Citation: Suggested Citation
