1. Common Causes of Chronic Kidney Disease 

  • Classification of the type of kidney disease is based on pathology, etiology and clinical history 
  • The most common causes of chronic kidney disease include: 
    1. Diabetic glomerulosclerosis (33%) 
    2. Vascular diseases (hypertension, renal artery stenosis) (21%)
    3. Glomerular diseases (primary or secondary) (19%)

2. Who to Test

Testing for CKD should not be universal, but should be targeted for individuals at increased risk of developing CKD:

  • Hypertension
  • Diabetes Mellitus
  • Family history of Stage 5 CKD or hereditary kidney disease
  • Vascular disease (prior diagnosis of CVD, stroke/TIA or PVD)
  • Multisystem disease with potential kidney involvement (e.g. SLE)

3. How to Test

  • For accurate diagnosis, retest eGFR, random urine ACR (albumin:creatinine ratio) and Urinalysis if not tested in the prior 6 months. 
  • In patients with a new finding of reduced eGFR, repeat eGFR to exclude causes of acute deterioration of eGFR (e.g. acute kidney injury, or initiation of ACEi or ARB therapy). 
  • In patients with a previous finding of an abnormal eGFR and ACR in the past 6 months, you do not have re-test. 

For more information please refer to the Chronic Kidney Disease (CKD) Clinical Pathway (www.ckdpathway.ca).  This resource for primary care providers can aid in the diagnosis, medical management, and referral of adults with CKD.

4. When to Refer to a Nephrologist 

Routine referral is recommended for any one of the following:

  • eGFR < 30 mL/min/1.73m2 , irrespective of albuminuria or hematuria. 
  • Persistent albuminuria (ACR > 60 mg/mmol), irrespective of hematuria. 
  • Hematuria sustained and not readily explained by a urinary tract source with: 
    • Persistent albuminuria (ACR 3 – 60 mg/mmol) irrespective of eGFR

- or -

  • eGFR < 60 mL/min/1.73m2
  • An unexplained, progressive decline in eGFR ≥ 5 mL/min/1.73m2 that occurs over 6 months, confirmed on repeat testing within 2-4 weeks (ACEi or ARBs can cause a reversible reduction in eGFR when initiated). 

Urgent referral is recommended for any one of the following:

  • Rapid decline in eGFR over days to weeks. 
  • eGFR declining over weeks to months PLUS hematuria and/or albuminuria. 
  • eGFR < 15 mL/min/1.73m2. 
  • Acute nephrotic syndrome (ACR > 180 mg/mmol or proteinuria > 3g/d). 
  • Suspected vasculitis / autoimmune disease in the setting of hematuria and/or albuminuria. 

Emergent referral is recommended for any one of the following:

  • New diagnosis of eGFR < 10 mL/min/1.73m2
  • Life threatening uremic symptoms (marked hyperkalemia > 6.5 mmol/L; pulmonary edema and kidney failure; pericarditis and kidney failure). 

In addition to the above, referral could be considered for any one of the following:

  • CKD and hypertension refractory to treatment with 4 or more antihypertensive agents. 
  • Persistent abnormalities of serum potassium. 
  • Recurrent or extensive nephrolithiasis. 
  • Hereditary kidney disease (e.g. polycystic kidney disease). 

For more information please refer to the CKD Pathway