Clinical and Experimental Nephrology
RATIONALE The definition of CKD remains intact, but we have clarified the classification and risk stratification as indicated below. The addition of ‘with implications for health’ is intended to reflect the notion that a variety of abnormalities of kidney structure or function may exist, but not all have implications for health of individuals, and therefore need to be contextualized. Kidney damage refers to a broad range of abnormalities observed during clinical assessment, which may be insensitive and non-specific for the cause of disease but may precede reduction in kidney function (Table 2). Excretory, endocrine and metabolic functions decline together in most chronic kidney diseases. GFR is generally accepted as the best overall index of kidney function. We refer to a GFR o60 ml/min/ 1.73 m as decreased GFR (Table 2) and a GFR o15 ml/min/ 1.73 m as kidney failure. AKI may occur in patients with CKD and hasten the progression to kidney failure. Complications include drug toxicity, metabolic and endocrine complications, increased risk for CVD, and a variety of other recently recognized complications, including infections, frailty, and cognitive impairment. Complications may occur at any stage, often leading to death without progression to kidney failure. Complications may also arise from adverse effects of interventions to prevent or treat the disease and associated comorbidity.