Cat Kidney Disease: 4 Stages Explained

By Dr. Sarah Mitchell · October 13, 2026

Chronic Kidney Disease (CKD)

CKD affects 30-50% of cats over 15 years old. The kidneys gradually lose function, but early detection can slow progression and maintain quality of life.

Stage 1: Early CKD

Kidney values are mildly elevated. Cats appear normal. Diagnosis often happens during routine blood work. This is the best time to intervene.

Stage 2: Mild CKD

Increased thirst and urination may begin. Blood work shows moderate elevation of creatinine and BUN. Dietary changes and hydration support start here.

Stage 3: Moderate CKD

Weight loss, decreased appetite, and vomiting may appear. Phosphorus binders, blood pressure medication, and subcutaneous fluids may be needed.

Stage 4: Severe CKD

Cats may be visibly ill with significant weight loss and lethargy. Intensive supportive care including daily fluids, appetite stimulants, and anti-nausea medication helps maintain comfort.