CKD Stages G1 and G2
CKD Stages G1 and G2
Identifying patients with CKD stages G1 & G2
An eGFR of >90 ml/min/1.73m² is considered normal kidney function. If these patients have evidence of kidney disease* however (see below) they should be classified as CKD stage G1.
Patients with an eGFR of 60-90 ml/min/1.73m² have mildly reduced kidney function which may be appropriate for their age. If these patients have any other evidence of kidney disease* (see below) they have CKD stage G2.
*Evidence of kidney disease, required to diagnose CKD in patients with an eGFR >60 ml/min/1.73m², may include:
- Proteinuria
- Haematuria (of presumed or proven renal origin)
- Structural abnormalities (e.g. reflux nephropathy, renal dysgenesis, medullary sponge kidney)
- A known diagnosis of a genetic kidney disease (e.g. polycystic kidney disease)
- Abnormalities detected by examination of renal histology
- Electrolyte abnormalities due to renal tubular disorders
- History of kidney transplantation
Initial assessment of CKD stages G1 and G2
The initial assessment for most of these patients will be undertaken in primary care settings.
The aim of the initial assessment is to determine which patients are at risk of progressive renal disease.
- All patients should have a urine specimen sent for measurement of the albumin:creatinine ratio (ACR).
- Urine reagent stick should be used to check for haematuria.
- If assessment is precipitated by a first discovery of an elevated serum creatinine level it is important to ensure that the renal function is stable. Previous blood tests, if available, will give you the answer. If no previous blood tests are available and the patient is well with no other worrying features (e.g. high potassium, symptoms of bladder outflow tract obstruction, severe hypertension), repeat the test within 14 days. Patients with deteriorating renal function require rapid assessment.
- Measure blood pressure. CKD can be a consequence of hypertension and CKD of any aetiology can be associated with hypertension. An elevated serum creatinine level may be the first clue that a patient is hypertensive.
Management of CKD stages G1 and G2
This applies to patients with stable stages G1 and G2 CKD. To diagnose CKD, two or more blood tests are required at least 90 days apart. The CKD staging and management outlined below is predicated on stable renal function.
Almost all patients with stages G1 and G2 CKD can be appropriately managed in primary care. The principal aim is to identify individuals at risk of progressive renal disease.
Some patients need further investigation where there are indications that progression to end stage renal failure (Stage G5) may be a possibility. These patients should usually be referred to the local nephrology service. Pointers to progression of renal disease include:
- Proteinuria – the risk is graded but a common cut-off for further investigation in patients without diabetes is ACR>70 mg/mmol or PCR>100 mg/mmol
- Haematuria of renal origin
- Rapidly deteriorating renal function
- Young age – the referral threshold should be much lower for younger patients in whom the lifetime risk of developing progressive kidney disease is higher.
- Family history of renal failure
- Hypertension which is difficult to control
Risk of cardiovascular events and death is substantially increased by the presence of CKD and or proteinuria and the risks of these two are additive. Patients with stages G1 and G2 CKD are much more likely to suffer a cardiovascular event than they are to require renal replacement therapy (dialysis or a transplant) in their lifetime. Patients should be offered lifestyle advice including recommendations for regular exercise, smoking cessation and attainment and maintenance of a healthy weight.
Long term monitoring of renal function, proteinuria and blood pressure should be performed for all patients. The principal aim of long term monitoring is to identify the minority of patients with stage G1 and G2 CKD who will go on to develop progressive renal disease.
- Renal function and proteinuria – patients with a urine ACR >3 mg/mmol (i.e. A2 and A3) should undergo annual monitoring of renal function and proteinuria. Patients with ACR<3 mg/mmol may be monitored less frequently (See more on stages of CKD). Patients with evidence of rapidly progressive renal impairment or who have worrying features (e.g. difficult to control hypertension, anaemia, hyperkalaemia, features of a systemic disease) should be considered for referral to renal services.
- Worsening proteinuria is an adverse prognostic sign. In patients with worsening proteinuria which exceeds ACR>70mg/mmol consider referral / discussion with nephrology unless it is known to be caused by diabetes and is appropriately treated. (See the management of patients with CKD section on Referral Guidelines).
- Blood pressure – Aim to keep the BP 140/90. In patients with CKD and diabetes or an ACR>70 mg/mmol aim to keep BP<130/80. (See the management of patients with CKD section on blood pressure (hypertension) management.)
- Cardiovascular disease – Offer advice on smoking cessation, exercise and lifestyle. (See the management of patients with CKD section on cardiovascular risk reduction.)
Patient information – CKD G1 and G2
CKD stage G1 is kidney disease with normal renal function. Patients with CKD stage G2 have mild impairment of kidney function. Most patients with CKD stages G1 and G2 just need occasional testing to ensure things are stable. A small minority of patients need further investigations to see if they have a disease which may benefit from treatment or could lead to more serious kidney damage.