Chronic kidney disease (CKD) is the term used to replace the older terms of chronic renal failure and renal insufficiency.
This recognizes that CKD has a spectrum of severity from asymptomatic kidney disease to end stage uremia. Although CKD tends
to be stable over the short term, it tends to progress to end-stage renal failure over months to years in most animals with
CKD. In the IRIS (International Renal Interest Society) staging system, CKD is classified into stages based on stable serum
creatinine concentration and into sub stages based on level of proteinuria and hypertension.
Dietary Treatment of Chronic Kidney Disease
Although dietary therapy is a foundational part of treatment of CKD, dietary treatment of early CKD in dogs and cats continues
to be controversial with respect to what dietary components are important to prevent progressive renal functional loss and
uremia.1 Recent randomized clinical trials show that renal diets result in lower mortality from uremic crises and uremic death compare
to maintenance diets in both dogs and cats with stage 2-3 CKD. It is not known exactly why renal diets are beneficial in these
2 clinical trials. Reasons that renal diets may be beneficial include restriction in dietary protein or phosphorus content,
-3 fatty acid supplementation of the diet, alkalinizing nature of the diet, potassium content (cats) or other factors. There
is no proof that dietary protein restriction independent of phosphorus restriction slows progression of CKD in dogs and cats. Dietary phosphorus restriction slows progression of induced models of CKD in dogs.
Diets high in -3 fatty acids (menhaden fish oil) are beneficial in treatment of some models of CKD and immune-mediated GN
compared to diets supplemented with -6 fatty acids.
It is also important that dogs and cats with CKD maintain adequate caloric intake to avoid protein-calorie malnutrition. Gradual
transition to the renal diet over 2-4 weeks resulted in excellent acceptance of the diet in cats with stage 2-3 CKD in one
clinical trial. Dogs and cats with stage 4 CKD often fail to eat sufficient food voluntarily, regardless of the palatability
or nutrient content. Monitoring for evidence of protein-calorie malnutrition should include monitoring for weight loss, hypoalbuminemia,
anemia, poor hair coat quality, muscle wasting and declining body condition scores. Diet consumption may be encouraged by
minimizing uremia by maintaining hydration, heating the food to room temperature, adding small amounts of water, tuna water
or clam juice, or adding garlic powder.