Chronic kidney disease (CKD), also referred to as chronic renal disease, is a progressive loss of renal function over a period of months or years. All individuals with a Glomerular filtration rate (GFR) less than 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 a 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 chronic kidney disease:
1. Loss of kidney function and
2. Development of cardiovascular disease
Stage 1 CKD [ICD – 9 585.1, ICD – 10 N18.1]
Slightly diminished function; Kidney damage with normal or increased GFR (>90 mL/min/1.73 m2). Kidney damage is defined as pathologic abnormalities or markers of damage, including abnormalities in blood or urine test or imaging studies
Stage 2 CKD [ICD – 9 585.2, ICD – 10 N18.2]
Mild reduction in GFR (60-89 mL/min/1.73 m2) with kidney damage. Kidney damage is defined as pathologic abnormalities or markers of damage, including abnormalities in blood or urine test or imaging studies.
Stage 3 CKD [ICD – 9 585.3, ICD – 10 N18.3]
Moderate reduction in GFR (30-59 mL/min/1.73 m2)
Stage 4 CKD [ICD – 9 585.4, ICD – 10 N18.4]
Severe reduction in GFR (15-29 mL/min/1.73 m2)
Stage 5 CKD [ICD – 9 585.5, ICD – 10 N18.5]
Established kidney failure (GFR <15 mL/min/1.73 m2, or permanent renal replacement therapy (RRT) Reference: http://www.kidney.org/professionals/KDOQI/guidelines_ckd/p4_class_g1.htm