Although kidney transplantation is the optimal therapy after kidney failure for prolonging patient survival and improving quality of life, kidneys transplanted from deceased donors often do not function longer than 10 to 15 years. Therefore, many recipients must eventually receive a second transplant or undergo dialysis, with considerations such as the scarcity of donor organs and the immunological sensitization of transplant recipients factoring into decisions related to these options.
Because direct comparison of transplantation versus dialysis continuation through a randomized controlled trial is not feasible due to ethical, biological, and logistic reasons, investigators recently conducted a retrospective study that analyzed data pertaining to 2346 adults with a failed first kidney transplant who were waitlisted for a second kidney transplant in Austria during 1980–2019 (1).
In the CJASN study, patients who received a second kidney transplant soon after a failed first transplant had a longer average survival time compared with those who underwent dialysis while remaining on the transplant waitlist. Rainer Oberbauer, MD, of the Medical University of Vienna, in Austria, is senior author of the study.
At a 10-year follow-up point, the overall mortality was 41%, and patients who underwent retransplantation lived for an average of 5.8 months longer than those who underwent dialysis. The difference in survival time with retransplantation was lower in patients who had a longer wait time after their first transplant failed, however. Patients who underwent retransplantation lived for an average of 8.0 months longer with a waiting time of less than 1 year but for 0.1 month with a waiting time of 8 years. There was no statistically significant survival difference in individuals with a waiting time of more than 3 years after first graft loss.
This decreased survival advantage was mainly a consequence of improved relative survival over time in patients who remained on dialysis awaiting transplantation, perhaps reflecting a biological selection of long-term survivors, the authors note.
Also, there was a higher survival benefit with second kidney transplants in recent years compared with earlier years, indicating advances in current transplant practices. Furthermore, kidney transplant recipients with living donors also appeared to have higher survival rates than those with deceased donors.
“Our data showed that a second transplantation is advantageous regarding gained life years; however, the difference to non-transplanted patients decreases with time on the waiting list,” Oberbauer said. “Nevertheless, patients might have a higher quality of life when transplanted and therefore should get a second transplant if a suitable donor organ is available.” Oberbauer stressed that patients with a failed first kidney transplant should be waitlisted immediately if they are fit to undergo a second transplantation.
An accompanying editorial notes that second kidney transplant candidates comprise a sizable portion of waiting-list populations—for example, 11.8% in the United States and 27.5% in Austria (2). The editorial's authors state that if the study's results are reproduced in additional countries, efforts should be made to decrease time on the waiting list for second kidney transplant candidates through measures such as expedited workup and enlistment of patients with failing first kidney transplants before they require dialysis.
References
- 1.↑
Kainz A, et al. Waiting time for second kidney transplantation and mortality. Clin J Am Soc Nephrol. [published online ahead of print December 29, 2021]. doi: 10.2215/CJN.07620621; doi: 10.2215/CJN.07620621; https://cjasn.asnjournals.org/content/early/2021/12/23/CJN.07620621
- 2.↑
Fallahzadeh MK, Birdwell KA. Waitlist mortality for second kidney transplants. Clin J Am Soc Nephrol. [published online ahead of print December 29, 2021]. doi: 10.2215/CJN.15021121; https://cjasn.asnjournals.org/content/early/2021/12/23/CJN.15021121