Rate of change in kidney function and the risk of death: the case for incorporating the rate of kidney function decline into the CKD staging system.

Chronic kidney disease (CKD) is associated with increased risk of death. A wave of recent studies used longitudinal data to examine the effect of the rate of decline of kidney function on the risk of death. The results from these studies show that there is an independent and graded association between the rate of kidney function decline and the risk of death. There is a need to incorporate the rate of decline in the definition of CKD. This redefinition of CKD will transform a static definition into a dynamic one that more accurately describes the disease state in an individual patient.