Progression of Kidney Disease in Kidney Transplant Recipients With a Failing Graft: A Matched Cohort Study.

Background: Few studies have assessed outcomes in transplant recipients with failing grafts as most studies have focused on outcomes after graft loss.

Objective: To determine whether renal function declines faster in kidney transplant recipients with a failing graft than in people with chronic kidney disease of their native kidneys.

Design: Retrospective cohort study.

Setting: Alberta, Canada (2002-2019).

Patients: We identified kidney transplant recipients with a failing graft (2 estimated glomerular filtration rate [eGFR] measurements 15-30 mL/min/1.73 m ≥90 days apart).

Measurements: We compared the change in eGFR over time (eGFR with 95% confidence limits, eGFR) and the competing risks of kidney failure and death (cause-specific hazard ratios [HRs], HR).

Methods: Recipients (n = 575) were compared with propensity-score-matched, nontransplant controls (n = 575) with a similar degree of kidney dysfunction.

Results: The median potential follow-up time was 7.8 years (interquartile range, 3.6-12.1). The hazards for kidney failure (HR1.33) and death (HR1.59) were significantly higher for recipients, while the eGFR decline over time was similar (recipients vs controls: -2.27 vs -2.21 mL/min/1.73 m per year). The rate of eGFR decline was associated with kidney failure but not death.

Limitations: This was a retrospective, observational study, and there is a risk of bias due to residual confounding.

Conclusions: Although eGFR declines at a similar rate in transplant recipients as in nontransplant controls, recipients have a higher risk of kidney failure and death. Studies are needed to identify preventive measures to improve outcomes in transplant recipients with a failing graft.