- Kidney damage for ≥ 3 months, as defined by structural or functional abnormalities of the kidney, with or without decreased GFR, manifest by either:
- Pathological abnormalities; or
- Markers of kidney damage, including abnormalities in the composition of the blood or urine, or abnormalities in imaging tests.
- GFR <60 mL/min/1.73 m² for ≥ 3 months, with or without kidney damage.
All individuals with GFR <60 mL/min/1.73 m² for ≥ 3 months are classified as having Chronic Kidney Disease, irrespective of the presence or absence of kidney damage. The rationale for including these individuals is that reduction in kidney function to this level or lower represents loss of half or more of the adult level of normal kidney function, which may be associated with number of complications.
All individuals with kidney damage are classified as having chronic kidney disease, irrespective of the level of GFR. The rationale for including individuals with GFR >60 mL/min/1.73 m² is that GFR may be sustained at normal or increased levels despite substantial kidney damage and that patients with kidney damage are at increased risk of the two major outcomes of CKD: loss of kidney function and development of cardiovascular disease.
The methods to estimate GFR and assess markers of kidney damage are not completely sensitive or specific in detecting decreased GFR and kidney damage, respectively. Thus misclassification is possible, and clinicians should carefully consider all aspects of the patient's clinical presentation in interpreting test results and determining evaluation and management. For the definition of CKD, the K/DOQI Work Group selected cut-off levels for GFR and markers of kidney damage that maximize specificity, acknowledging potential loss of sensitivity.
Clinicians should be especially careful in the evaluation of individuals with borderline abnormal results for markers of kidney disease, mild decrease in GFR (60-89 mL/min/1.73 m² ), high blood pressure, diabetes, and of other individuals at increased risk of Chronic Kidney Disease.
K/DOQI Clinical Practice Guidelines
