Identifying patients with CKD stage G3
Patients with CKD stage G3 (eGFR 30-59 ml/min/1.73m2) have impaired kidney function. These patients can be further subdivided based on their eGFR as follows:
- CKD stage G3a: eGFR 45-59 ml/min/1.73m2
- CKD stage G3b: eGFR 30-44 ml/min/1.73m2
Remember that eGFR is only an estimate of kidney function (more info on eGFR) and may require adjustment depending on the patient’s race.
Creatinine and eGFR in an individual are usually quite stable. Deteriorating renal function needs rapid assessment. Note that the guidance on CKD staging and management outlined below are only applicable to patients with stable renal function.
Initial assessment of CKD stage G3
The initial assessment of these patients should be undertaken in the primary care setting for the majority of patients. The principle aim of the initial assessment is to identify individuals at risk of progressive renal disease.
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.
- Clinical assessment –
Consider obstruction in patients with prominent urinary tract symptoms or suggestive clinical findings (e.g. palpable bladder).
Is the patient well? Is there a history of significant associated disease? Consider referral if patient is unwell, a systemic disease process involving kidneys is suspected and / or supported by urinary abnormalities or other indicators.
- Medication review – are there any potentially nephrotoxic drugs or drugs that need dose alterations in patients with renal impairment? Remember non-prescribed and over the counter medications, e.g. NSAIDs.
- Urine tests: dipstick for blood and quantitation of proteinuria by ACR or PCR. Presence of haematuria or proteinuria may suggest intrinsic renal disease.
- Think if the CKD could be a complication of an existing diagnosis or a presenting feature of a new diagnosis e.g. diabetes, hypertension, multiple myeloma, connective tissue disease
- Is there a family history of CKD or renal failure? May suggest a heritable disease, such as ADPKD, Alport’s syndrome, reflux nephropathy
- Imaging – exclusion of obstruction is indicated in patients with significant urinary symptoms or in whom there is a clinical suspicion of obstruction. An ultrasound scan of the renal tract is the usual screening investigation in this setting.
Management of CKD stage G3
This applies to patients with stable CKD stage G3.
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 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 CKD stage G3 are, on average, 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. Consider offering patients Atorvastatin 20 mg for the primary and secondary prevention of cardiovascular disease. (see more on cardiovascular disease).
Long term monitoring of renal function, proteinuria and blood pressure should be performed for all patients. The aims of monitoring are to identify the minority of patients with CKD stage G3 who will progress to end-stage renal failure and to identify complications of CKD.
- Renal function should be monitored at least annually. For patients with significant proteinuria (i.e. A3) the renal function should be checked at least twice yearly. Consider referring patients to nephrology with rapidly declining renal function, i.e. a sustained decrease in GFR of 25% or more and a change in GFR category, or a sustained decrease in GFR of 15 ml/min/1.73 m2 or more within 12 months.
- Haemoglobin – if low, first exclude “non-renal” aetiologies. Haemoglobin levels fall progressively commensurate with deteriorating renal function although significant anaemia attributable to CKD is rare before CKD stage G3b or G4. For patients with haemoglobin levels approaching or below 100 g/L specific interventions may be considered. (see more on anaemia).
- Proteinuria – monitor with serial ACR or PCR. Note the suggested thresholds of ACR>70 (or PCR>100) mg/mmol for more stringent blood pressure targets and ACR>70 (or PCR>100) mg/mmol or ACR >30 (or PCR >50) with hematuria for specialist referral/discussion. (see more on proteinuria)
- 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 more on hypertension)
- Cardiovascular risk – offer advice on smoking, exercise and lifestyle. Consider offering Atorvastatin 20 mg nocte for the primary and secondary prevention of cardiovascular disease. (see more on Cardiovascular disease).
- Immunisation – influenza and pneumococcal
- Medication review – regular review of medication to minimise nephrotoxic drugs (particularly NSAIDs) and ensure doses of others are appropriate to renal function.
Patient information – CKD stage G3
Patients with CKD stage G3 have impaired kidney function. Only a minority of patients with CKD stage G3 go on to develop more serious kidney disease. Cardiovascular disease, the umbrella term for diseases of the heart and circulation (e.g. heart attacks and strokes), is more common in patients with CKD. It is important to try and identify which patients may go on to develop more serious kidney damage and to try and reduce the chances of patients developing cardiovascular disease.