Chronic kidney disease (CKD) is one of the most common conditions affecting middle-aged and senior cats. An estimated 30-50% of cats over fifteen years of age have some degree of kidney dysfunction. The kidneys filter waste from the blood, regulate fluid balance, and maintain electrolyte levels — when they fail, the effects cascade through the entire body.
Why Cats Are Prone to Kidney Disease
Cats evolved as desert animals with highly efficient kidneys designed to concentrate urine and conserve water. This evolutionary adaptation, which serves wild cats well in arid environments, may predispose domestic cats to kidney problems when they eat dry-food diets that do not provide adequate moisture. The domestic cat's kidney structure is different from dogs or humans in ways that make them particularly vulnerable to progressive kidney damage.
Stages of CKD
CKD is classified into four stages based on blood work and urinalysis findings. Stage 1 is the earliest — kidney values may be normal on blood work but urinalysis shows dilute urine. Stages 2, 3, and 4 represent progressively worsening kidney function. The earlier CKD is detected, the more treatment options are available to slow progression.
Management and Diet
The cornerstone of CKD management is a prescription kidney diet — which is lower in phosphorus and protein than regular cat food, with carefully balanced electrolytes. These diets significantly extend survival time in cats with CKD. Other treatments include phosphate binders (if dietary phosphorus restriction is insufficient), medications to manage blood pressure and protein loss in urine, and subcutaneous fluid therapy to compensate for reduced kidney function.