An Australian group of researchers examined the potential of percentage decline in eGFR as a surrogate for hard outcomes in kidney transplant recipients. Their conclusion: A 30% decline in eGFR between years 1 and 3 after kidney transplant is i) common and ii) strongly associated with risks of subsequent death and death-censored graft failure. The authors now call for percentage decline in eGFR to be used as a surrogate outcome in kidney transplant trials.

The analysis was based on data from the “Australia and New Zealand Dialysis and Transplant Registry”, which includes almost 8,000 transplants performed between 1995 and 2009, amounting to 71,845 patient-years of follow-up, 1,121 graft losses and 1,192 deaths. For these cases, the authors determined the risks of death or death-censored graft failure related to percentage change in eGFR between years 1 and 3 after transplant.

What they found was an association of eGFR decline with exponentially increased risks of graft failure and death: Compared to a stable eGFR, a ≥30% decline in eGFR was associated with a twofold increased risk of subsequent death (hazard ratio, 2.20) and a more than fivefold increased risk of death-censored graft failure (5.14); this ≥30% decline was observed in 10% of patients. In addition, the marker ‘decline in eGFR’ was superior to other surrogates that were investigated, such as acute rejection, doubling of serum creatinine level and eGFR at year 1 or year 2.

A ≥30% decline in eGFR between years 1 and 3 after kidney transplant is a common occurrence and showed a strong association with risks of subsequent death and death–censored graft failure, conclude the authors. Percentage decline in eGFR should therefore be considered as surrogate outcome in kidney transplant trials.

Source: Clayton P. A. et al.: “Relationship between eGFR Decline and Hard Outcomes after Kidney Transplants”, JASN, November 2016.