If a patient is newly discovered to have a high creatinine it is important to establish if it represents acute kidney injury (AKI) or CKD. A patient cannot be labelled as having CKD unless you know that the renal function is stable or in steady state. On finding an elevated serum creatinine in the absence of previous creatinine results, assuming the patient is well and there are no worrying clinical or biochemical features (especially potassium), recheck the serum creatinine within 7-14 days to determine the rate of change.
Acute kidney injury – Management of AKI is outside the scope of this guideline but declining renal function over hours to days needs urgent assessment. Sometimes the cause is immediately apparent (e.g. bladder outflow obstruction or drugs) and quickly remediable. If not, urgent hospital assessment is almost always required. Refer according to local protocols or see the London AKI Network or Think Kidneys for further information.
Once a patient has been identified as having CKD it is important to determine the rate of progression. To determine the rate of progression obtain a minimum of 3 GFR estimations over a period of not less than 90 days.
Consider referral to renal services if patients have rapidly progressive CKD as these patients are at increased risk of progression to end-stage kidney disease. NICE defines accelerated CKD progression as:
- A sustained decrease in GFR of 25% or more AND a change in GFR category (i.e. CKD “G” stage) within 12 months
- A sustained decrease in GFR of ≥15 ml/min/1.73m2 within 12 months
Slower rates of CKD deterioration may need specialist assessment, particularly if:
- CKD stage 4 (GFR<30 ml/min/1.73m2) is reached
- Proteinuria and / or haematuria are present
- Diagnostic uncertainty regarding the aetiology of the CKD
- There are symptoms suggestive of systemic disease
- Associated biochemical abnormalities, e.g. hyperkalaemia, hypocalcaemia
- Progressive anaemia
See referral guidance for more information.
Information for patients
Most patients who are newly discovered to have poor kidney function have an old problem which is changing slowly. It is important to identify those patients whose kidney function is changing more quickly. In many cases, changes to the medicines or other simple changes will be enough to put things right, although some patients may need further investigations and specialist treatment.