Impact of older donor age in kidney transplantation: A biopsy-based observational study

Results from the biopsy-based, observational INTERCOMEX (NCT01299168) and Trifecta-Kidney (NCT04239703) studies, which evaluated the effect of older donor age on molecular injury and rejection in kidney transplantation, were published in JCI Insight by Madill-Thomsen et al. Multivariable adaptive regression splines (MARS) analysis was used to adjust for confounders in the relationship of donor age to recipient age, donor type, and time of biopsy after transplant. The analysis included 4,502 kidney transplant biopsies from 3,611 patients.  

Key data: Older donor age correlated with lower estimated glomerular filtration rate (eGFR), increased acute kidney injury (AKI) and chronic injury transcripts, and greater failed repair scores at intermediate post-transplant timepoints, but had no effect on rejection, which was inversely correlated with recipient age. Donor age accounted for only 1.4% of variance in injury and repair–associated transcript (IRRAT) scores and 9% of eGFR variance. Neither donor age (p = 0.48) nor recipient age (p = 0.13) was significantly associated with 3-year post-biopsy graft survival. 

Key learning: Despite statistically significant associations with molecular injury and reduced eGFR, the overall contribution of older donor age to kidney transplant injury, function, and survival was relatively small, suggesting that current high discard rates of older donor kidneys warrant re-examination in the context of organ waitlist demand.