US deceased kidney transplantation: Estimated GFR, donor age and KDPI association with graft survival

Abstract

Background: Despite a significant shortage of kidneys for transplantation in the US, kidneys from older deceased donors are infrequently transplanted. This is primarily over concern of graft quality and transplant durability.

Methods: The US national transplant database (2000-2018) was assessed for deceased donor kidney transplant patient and graft survival, graft durability and stratified by donor age (<65 years>), Kidney Donor Profile Index (KDPI) and estimated glomerual filtration rate (GFR) one year post-transplantation (eGFR-1) were calculated.

Findings: Recipients of kidneys transplanted from deceased donors >65 years had a lower eGFR-1, (median 39 ml/min) than recipients of younger donor kidneys (median 54 ml/min). However, death-censored graft survival, stratified by eGFR-1, demonstrated similar survival, irrespective of donor age or KDPI. The durability of kidney survival decreases as the achieved eGFR-1 declines. KDPI has a poor association with eGFR-1 and lesser for graft durability. While recipients of kidneys > 65 years had a higher one year mortality than younger kidney recipients, recipients of kidneys > 65 years and an eGFR-1 <30 ml/min, had a lower survival than an untransplanted waitlist cohort (p<0.001).

Interpretation: The durability of kidney graft survival after transplantation was associated with the amount of kidney function gained through the transplant (eGFR-1) and the rate of graft loss (return to dialysis) was not significantly associated with donor age. 24.9% of recipients of older donor kidneys failed to achieve sufficient eGFR-1 providing a transplant survival benefit. While there is significant benefit from transplanting older kidneys, better decision-making tools are required to avoid transplanting kidneys that provide insufficient renal function.

Funding: None.

Keywords: AUC, area under curve; Age; CI, Confidence Interval; CKD, chronic kidney disease; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration Equation; CPRA, calculated panel-reactive antibody; DCD, donation after circulatory death; Donation; ESRD, end stage renal disease; Glomerular filtration rate (GFR); HHS, Department of Health and Human Services of the US government; HRSA, Health Resources and Services Administration, Agency within HHS; KDIGO, Kidney Disease Improving Global Outcomes; KDPI, kidney donor profile index; KDRI, kidney donor risk index; OPTN, Organ Procurement and Transplantation Network; Outcomes; Transplantation; eGFR, estimated glomerular filtration rate; eGFR-1, one year after transplantation.

Fig. 1

Distribution of eGFR-1 observed in adult deceased donor kidney transplant recipients segregated by donor age. <45 years (blue), <46–64 years (green) and 65+ years (orange).

Fig. 2

Death-censored (a) and non-death-censored (b) Kaplan-Meier Graft Failure Rates (95% CIs) categorized by deceased donor age and recipient eGFR-1. Solid lines kidney transplants from donors < 65 years, dashed lines were from donors over 65 years. Solid lines incorporate the 95% CI. Renal function stratified <30 ml/min (orange), 31–44 ml/min (green) and >45 ml/min (blue).

Fig. 3

Kaplan-Meier Graft Failure Rates (95% CIs) of deceased donor >65 years, kidney transplants surviving one year, subsequent graft survival is stratified by either a) recipient eGFR-1 or b) donor KDPI. eGFR stratifications: <30 ml/min (orange), 31–44 ml/min (green), >45 ml/min (blue). KDPI stratifications, 0–85% (blue), 86–95% (purple) and 96–100% (gold).

Fig. 4

Kaplan-Meier recipient survival (95% CIs) stratified by deceased donor age and the amount of recipient eGFR-1 (<30 ml/min (orange), 31–44 ml/min (green) and >45 ml/min (blue)). Survival of non-transplanted cohort of candidates awaiting kidney transplant, who were matched to recipients of >65 year kidneys, is shown (solid black line). Because the measurements of eGFR after one year necessitates survival for the first year, KM estimates begin at the observed one-year survival rate observed for each donor age group. The cohort survival was 100% at the time of matching with recipients.