Survival benefit of deceased donor kidney transplantation versus continued dialysis: international target trial emulation

OBJECTIVE: To quantify the survival benefit of deceased donor kidney transplantation versus continued dialysis according to patients' characteristics (age, diabetes, cardiovascular disease), donor quality (standard criteria donor or expanded criteria donor) and donor retrieval type (donation after brain death or donation after circulatory death). DESIGN: Target trial emulation. SETTING: European Renal Association Registry data from five countries or regions: Catalonia (Spain), Denmark, France, Norway, and the UK. PARTICIPANTS: Patients aged ≥20 years receiving dialysis and waitlisted for a first deceased donor kidney-only transplant between 2000 and 2019. MAIN OUTCOME MEASURES: Five year patient survival following deceased donor kidney transplantation versus continued dialysis within monthly sequential trials. Flexible parametric spline models estimated adjusted five year patient survival across recipient age. RESULTS: Of 64 036 waitlisted patients receiving dialysis, 39 244 received a deceased donor kidney transplant: 16 897 (43.1%) from a standard criteria donor/donation after brain death donor, 4324 (11.0%) from a standard criteria donor/donation after circulatory death donor, 14 799 (37.7%) from an expanded criteria donor/donation after brain death donor, and 3224 (8.2%) from an expanded criteria donor/donation after circulatory death donor. Standard criteria donor/donation after brain death and standard criteria donor/donation after circulatory death transplantation showed higher estimated five year survival compared with continued dialysis regardless of recipient age. However, the survival benefit associated with expanded criteria donor/donation after brain death transplantation and, particularly, expanded criteria donor/donation after circulatory death transplantation decreased with increasing recipient age, albeit with greater statistical uncertainty among older patients. For example, among 75 year olds, estimated five year survival following expanded criteria donor/donation after circulatory death transplantation did not differ significantly from that with continued dialysis (59% (95% confidence interval 51% to 66%) versus 55% (54% to 55%); hazard ratio 0.97, 95% confidence interval 0.70 to 1.33), irrespective of diabetes or cardiovascular disease status. This group had a threefold higher early post-transplant mortality than those continuing dialysis. CONCLUSIONS: Standard criteria donor kidney transplantation was consistently associated with a survival benefit compared with continued dialysis. By contrast, the survival benefit associated with expanded criteria donor transplantation declined with increasing recipient age, particularly for expanded criteria donor/donation after circulatory death transplantation, such that the oldest recipients had a smaller and more statistically uncertain estimated survival advantage over continued dialysis.