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    Understanding Feline Chronic Kidney Disease: Staging and Management Updates

    PetChart TeamFebruary 18, 20269 min readIncludes cited sources

    Prevalence


    Chronic kidney disease (CKD) is one of the most common conditions in aging cats. Studies estimate that 30–40% of cats over age 10 are affected.


    IRIS Staging


    The International Renal Interest Society (IRIS) staging system:


    • Stage 1: Creatinine <1.6 mg/dL, SDMA <18 — Non-azotemic, CKD confirmed by other findings
    • Stage 2: Creatinine 1.6–2.8, SDMA 18–25 — Mild azotemia, usually mild signs
    • Stage 3: Creatinine 2.9–5.0, SDMA 26–38 — Moderate azotemia, various clinical signs
    • Stage 4: Creatinine >5.0, SDMA >38 — Severe azotemia, significant clinical signs

    IRIS further sub-stages based on proteinuria (UPC ratio) and blood pressure.


    Early Detection with SDMA


    SDMA can detect reduced GFR when as little as 25% of kidney function is lost, compared to creatinine which may not elevate until 75% is compromised.


    Management by Stage


    • Stage 2: Renal diet (restricted phosphorus/protein), phosphate binders if needed
    • Stage 3: Add subcutaneous fluids, anti-nausea medications, potassium supplementation
    • Stage 4: Intensive supportive care, quality of life assessment

    Practice Tips


    1. Screen every cat over 7 with SDMA/creatinine in wellness panels
    2. Use consistent IRIS staging in medical records
    3. Set up automated rechecks based on stage-appropriate intervals

    Sources: IRIS CKD Staging Guidelines 2023; ISFM CKD Guidelines.

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