Chronic Kidney Disease in Cats: Welfare and Management

Feline Chronic Kidney Disease (CKD)

Chronic kidney disease (CKD) is the most common serious illness affecting older cats, with prevalence rising to approximately 30–40% of cats over 15 years of age. It is a progressive, irreversible condition resulting in gradual loss of functional nephrons and declining ability to filter waste products, regulate fluid balance, and produce key hormones. Understanding CKD management is essential for maximising quality of life and minimising suffering in affected cats.

Welfare Impact of CKD

CKD affects welfare through multiple mechanisms:

Uraemic toxin accumulation: Causes nausea, anorexia, lethargy, and oral ulceration in advanced disease
Dehydration: Cats with CKD produce large volumes of dilute urine, creating ongoing risk of dehydration and associated malaise
Hypertension: Up to 65% of CKD cats develop systemic hypertension, causing retinal haemorrhage, blindness, and neurological signs
Anaemia: Reduced erythropoietin production causes non-regenerative anaemia — lethargy, weakness, reduced quality of life
Hypokalaemia: Low potassium causes muscle weakness and neck ventroflexion
Phosphate retention: Accelerates renal deterioration and causes secondary hyperparathyroidism

Staging and Prognosis (IRIS System)

The International Renal Interest Society (IRIS) provides a staging framework based on creatinine and SDMA levels:

Stage 1: Non-azotaemic; early detection phase; prognosis good with management
Stage 2: Mild azotaemia; median survival 1,151 days with management
Stage 3: Moderate azotaemia; median survival 778 days
Stage 4: Severe azotaemia; median survival 103 days; comfort care priority

SDMA (symmetric dimethylarginine) detects CKD earlier than creatinine — flagging kidney decline when only 25% of function is lost, vs. 75% loss required for creatinine elevation.

Management Strategies

Dietary Management

Renal diets (phosphate-restricted, protein-moderately-reduced, omega-3 enriched) are the most evidence-based intervention — shown to extend survival significantly
Transition gradually — palatability is critical; a cat that refuses renal diet derives no benefit
Add renal-appropriate toppers or wet food to encourage intake if dry food refusal occurs
Phosphate binders (aluminium hydroxide, lanthanum carbonate) if dietary restriction alone insufficient

Hydration Support

Encourage water intake: multiple bowls, water fountains, wet food transition
Subcutaneous fluid administration at home — taught to owners by veterinary team — significantly improves quality of life in dehydrated cats
Typical maintenance: 100–150ml subcutaneously every 1–3 days depending on stage

Hypertension Management

Amlodipine (0.625–1.25mg/cat/day) — first-line antihypertensive for cats
Target systolic blood pressure <160mmHg
Monitor every 1–3 months once stable

Anaemia Management

Darbepoetin alpha (erythropoiesis-stimulating agent) for Hct <20%
Iron supplementation when using ESAs
Blood transfusion for severe acute anaemia

Quality of Life Monitoring

Key owner-observable quality of life indicators:

Appetite and food interest (weight trends monthly)
Grooming behaviour and coat quality
Social interaction and interest in environment
Mobility and ability to reach litter tray/food bowl comfortably
Nausea signs (lip licking, drooling, repeated swallowing)
Number of good days vs. difficult days per week

Monitoring Schedule

Regular monitoring enables timely management adjustments:

Stage 2: Every 3–6 months (bloodwork, urine protein:creatinine, blood pressure)
Stage 3: Every 2–3 months
Stage 4: Every 4–8 weeks or as clinically indicated