Supplementary Material for: Long-Term Outcomes of Kidney Transplants from Older/Marginal Donors: A Cohort Study

<b><i>Introduction:</i></b> To safely expand the donor pool, we introduced a strategy of biopsy-guided selection and allocation to single or dual transplantation of kidneys from donors &gt;60 years old or with hypertension, diabetes, and/or proteinuria (older/marginal donors). Here, we evaluated the long-term performance of this approach in everyday clinical practice. <b><i>Methods:</i></b> In this single-center cohort study, we compared outcomes of 98 patients who received one or two biopsy-evaluated grafts from older/marginal donors (“recipients”) and 198 patients who received nonhistologically assessed single graft from ideal donors (“reference-recipients”) from October 2004 to December 2015 at the Bergamo Transplant Center (Italy). <b><i>Results:</i></b> Older/marginal donors and their recipients were 27.9 and 19.3 years older than ideal donors and their reference-recipients, respectively. KDPI/KDRI and donor serum creatinine were higher and cold ischemia time longer in the recipient group. During a median follow-up of 51.9 (interquartile range 23.1–88.6) months, 11.2% of recipients died, 7.1% lost their graft, and 16.3% had biopsy-proven acute rejection (BPAR) versus 3.5, 7.6, and 17.7%, respectively, of reference-recipients. Overall death-censored graft failure (rate ratio 0.78 [95% CI 0.33–2.08]), 5-year death-censored graft survival (94.3% [87.8–100.0] vs. 94.2% [90.5–98.0]), BPAR incidence (rate ratio 0.87 [0.49–1.62]), and yearly measured glomerular filtration rate decline (1.18 ± 3.27 vs. 0.68 ± 2.42 mL/min/1.73 m², <i>p</i> = 0.37) were similar between recipients and reference-recipients, respectively. <b><i>Conclusions:</i></b> Biopsy-guided selection and allocation of kidneys from older/marginal donors can safely increase transplant activity in clinical practice without affecting long-term outcomes. This may help manage the growing gap between organ demand and supply without affecting long-term recipient and graft outcomes.