Improving early detection of chronic kidney disease.

Chronic kidney disease (CKD) is defined as either a reduction in measured kidney function (eGFR) or urinary abnormalities (haematuria/proteinuria) or a combination of both, present for more than 3 months. In the most recent NICE guidelines the various CKD stages 1-5 are now represented by G (for GFR) categories (G1-5) which have the same eGFR thresholds as previous CKD guidelines. The urinary albumin:creatinine ratio (ACR) category is denoted as A (for albuminuria) with three categories: A1, A2 or A3. The ACR category has been introduced to emphasise that patients with higher levels of albuminuria have an increased risk of progression to end-stage renal disease. Individuals with newly identified reduced eGFR should have acute kidney injury excluded. All newly identified CKD patients should have blood pressure, dipstick urinalysis, random urine ACR or urine protein:creatinine ratio (PCR), glucose, cholesterol and full blood count checked at the earliest opportunity. An ultrasound scan should be offered to patients at increased risk. Cardiovascular events and progression of CKD are more common if albuminuria or proteinuria is present. Urine ACR has a greater sensitivity for low levels of proteinuria in comparison with PCR. Referral for patients with CKD should be based on assessment of kidney function (eGFR), the severity of proteinuria (urine ACR), concerns about poorly controlled BP, or suspected inherited renal disease. Most cases of CKD in the elderly are caused by the cumulative effect of other disease states, especially hypertension and atherosclerosis. The CKD classification system will identify many elderly patients with a low eGFR but without progressive kidney failure.