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(2) ≥90 days apart). MEASUREMENTS: We compared the change in eGFR over time (eGFR with 95% confidence limits, (LCL)eGFR(UCL)) and the competing risks of kidney failure and death (cause-specific hazard ratios [HRs], (LCL)HR(UCL)). 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 (HR(1.10)1.33(1.60)) and death (HR(1.21)1.59(2.07)) were significantly higher for recipients, while the eGFR decline over time was similar (recipients vs controls: (–2.60)–2.27(–1.94) vs (–2.52)–2.21(–1.90) mL/min/1.73 m(2) 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.