Identification and Characterization of Kidney Transplants With Good Glomerular Filtration Rate at 1 Year But Subsequent Progressive Loss of Renal Function

Background After the first year after kidney transplantation, 3% to 5% of grafts fail each year but detailed studies of how grafts progress to failure are lacking. This study aimed to analyze the functional stability of kidney transplants between 1 and 5 years after transplantation and to identify initially well-functioning grafts with progressive decline in allograft function. Methods The study included 788 adult conventional kidney transplants performed at the Mayo Clinic Rochester between January 2000 and December 2005 with a minimum graft survival and follow-up of 2.6 years. The modification of diet in renal disease equation for estimating glomerular filtration rate (eGFRMDRD) was used to calculate the slope of renal function over time using all available serum creatinine values between 1 and 5 years after transplantation. Results Most transplants demonstrated good function (eGFRMDRD ≥40 mL/min) at 1 year with positive eGFRMDRD slope between 1 and 5 years after transplantation. However, a subset of grafts with 1-year eGFRMDRD ≥40 mL/min exhibited strongly negative eGFRMDRD slope between 1 and 5 years suggestive of progressive loss of graft function. Forty-one percent of this subset reached graft failure during follow-up, accounting for 69% of allograft failures occurring after 2.5 years after transplantation. This pattern of progressive decline in estimated glomerular filtration rate despite good early function was associated with but not fully attributable to factors suggestive of enhanced antidonor immunity. Conclusions Longitudinal analysis of serial estimated glomerular filtration ratemeasurements identifies initially well-functioning kidney transplants at high risk for subsequent graft loss. For this subset, further studies are needed to identify modifiable causes of functional decline.