KISS: Chronic Kidney Disease

Based on NICE NG203, 2021 & NICE TA775, 2022 & TA942 2023

Classification:

• CKD is classified according to estimated GFR and proteinuria using albumin-creatinine ratio (ACR):
  • G is used to denote the GFR category, G1-G5
  • A for the ACR category, A1-A3
• Increased ACR and decreased GFR are associated with adverse outcomes.
• Increased ACR and decreased GFR multiply these risks e.g. G2A1 = low risk of adverse outcomes, but G3bA2 = high risk and G3bA3 = very high risk (see heat map for risk according to GFR and A category).

Investigation:

• eGFR testing:
  • If the first discovery of low eGFR/raised creatinine, clinically assess carefully and if well repeat the test within 14 days to exclude acute kidney injury. If eGFR is stable, repeat again at 3 months to see if it is sustained. 
  • If low eGFR is sustained >90 days, CKD is diagnosed.
  • Interpret eGFR with caution in those with extremes of muscle mass e.g. reduced muscle mass will lead to over-estimation of eGFR this has implications when interpreting levels of frailty.
• Proteinuria Testing:
  • Do not use reagent strips to identify proteinuria, test for CKD with eGFR and ACR.
  • If the initial ACR is between 3 and 70, this should be confirmed with an early morning sample:
    • Confirmed ACR > 3 is considered clinically important.
  • If the initial level is over 70, a repeat is not needed.
• Indications for renal ultrasound:
  • Accelerated progression of CKD.
  • Persistent invisible haematuria.
  • Symptoms of urinary tract obstruction.
  • Family history of polycystic kidney disease.
  • GFR category G4 or G5.

Chronic Kideny Disease: Management:

NICE NG203, 2021  Cochrane 2023  BJGP2018;68:356  NICE TA775, 2022  TA942 2023  BMJ 2023;383:e074216

Inform:

• Optimise risk factors e.g. lifestyle, hypertension, diabetes etc & direct patients to Information Sources.

Monitor for progression:

• Regular monitoring of eGFR:
  • G1-3a at least annually, G3b-G4 at least 6 monthly, G5 3 monthly.
• Check for accelerated progression:
  • = a change in G category & a sustained decrease in eGFR of >25%, or a decrease in eGFR of 15 per year.
• Assess the 5-year risk of needing renal replacement Kidney Failure Risk Equation.

Reducing cardiovascular risk, anaemia and bones:

• Lifestyle advice; avoid NSAIDs.
• Lower BP: Target BP < 140/90; lower target <130/80 if ACR> 70.
  • Follow usual hypertension guidelines if ACR < 30 (i.e. groups A1 and A2).
  • Offer ACEi or ARB if ACR > 30 (A3).
    • ACEi and ARBs may be associated with a temporary fall in eGFR after starting ACEi or ARBs of up to 25% or rise in Cr of 30% - if so repeat after 1-2 weeks but don't change dose and accept a drop in eGFR <25% or a rise in Cr <30%.
    • Seek specialist advice if sustained and significant change. 
    • Do not start if serum K >5, and stop if serum K >6.
• Proteinuria:
  • If CKD and diabetes (NG28 Nov 2021) offer ACEi or ARB if ACR > 3.
  • If CKD without diabetes, refer for nephrology assessment if ACR > 70.
• SGLT inhibitors dapagliflozin and empagliflozin are now an option as add on to max tolerated ACEi/ARB:
  • Dapagliflozin if eGFR of 25-75 ml/min/1.73 m² AND type 2 diabetes OR have a urine ACR of ≥ 22.6 mg/mmol.
  • Empagliflozin if eGFR of 20-45 ml/min/1.73 m² OR
    • eGFR 45-90 ml/min/1.73 m² AND either a urine ACR of ≥22.6 mg/mmol or type 2 diabetes.
• Statins: offer atorvastatin 20mg to  patients with CKD not requiring dialysis for 1⁰ and 2⁰ prevention of CVD NICE2023
  • if the target is not met, and eGFR is > 30 then increase the dose; if eGFR is < 30 get specialist renal advice.
• Antiplatelets - offer only for secondary prevention of CVD.
• Anaemia: Consider investigating and managing anaemia in adults with CKD if Hb ≤ 110 g/L:
  • If eGFR is > 60 ml/min investigate other causes of anaemia as it is unlikely to be due to CKD.
  • If eGFR is 30 - 60 ml/min investigate other causes of anaemia, but use clinical judgement to decide how extensive those investigations should be as the anaemia may be caused by CKD.
  • If eGFR is < 30 ml/min think about other causes, but note anaemia is often caused by CKD.
• Bones
  • Serum calcium, phosphate and PTH levels need to be measured in patients with category G4 or G5 (i.e. eGFR<30) and obtain specialist advice. Offer cholecalciferol to treat Vit D deficiency if found.

Referral criteria

• 5-year risk of needing renal replacement therapy > 5% using the Kidney Failure Risk Equation.
• Stage A3 (ACR>30) plus haematuria OR ACR >70, unless secondary to diabetes and on treatment.
• Accelerated progression (see monitoring above).
• Hypertension is poorly controlled despite at least 4 drugs at therapeutic doses.
• Suspected renal artery stenosis, or suspected rare or genetic cause.