Page 634 - WSAVA2018
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 25-28 September, 2018 | Singapore
follows2: phosphorus restriction, high quality protein moderation, sodium control, B vitamin fortification, and alkalization (the only feline diets to promote so). The potassium content is usually higher than typical maintenance diets, although it varies from brand to brand. Some of them also include long chain omega 3 fatty acids EPA and DHA.
Cats with CKD have typically waxing and waning appetite, which is why CKD diets are and energy dense (high fat, low fiber). These diets are high in energy density (thus, low in fiber and high in fat) to promote adequate energy intake even in the face of occasional inappetence. Both dry and canned use this strategy, but canned foods, by virtue of their high moisture content, are less energy dense than dry foods.
The most important modification in CKD diets is phosphorus restriction (below 1 g/1000 Kcal, in
general), which is indicated to address renal secondary hyperparathyroidism, and this strategy is believed to slow down progression of CKD. The IRIS society (www. recommends the use of low phosphorus diets initially (stage II onwards), but recommends the addition of phosphate binders at later stages, where dietary restriction is not enough.
These diets have moderate sodium concentrations as a precaution due to the likelihood of hypertension in these patients, although the effect of dietary sodium on blood pressure is unclear. Sodium is never truly restricted, because a very low sodium diet can stimulate the renin angiotensin aldosterone axis and result in hypertension3. Most diets maintenance diets provide 1 g/1000 Kcal, and renal diets range from 0.5 to 1 g/1000 Kcal.
Potassium content varies amongst feline CKD diets (from 1.5 to 3.5 g/1000 Kcal, approximately). In hyperkalemic patients (e.g. some patients treated with ACE inhibitors), choosing the lowest K diet available is indicated.
For hypokalemia, high K diets can be chosen (or, alternatively, potassium can be supplemented orally).
Protein should never be restricted. Providing all
nitrogen and essential amino acids is essential and protein deficiency will result in lean mass loss and
worse prognostic. Diets for CKD are always above the requirement, but they tend to be lower than typical maintenance diet to minimize nitrogen waste product formation and accumulation, which contribute to uremia. Dietary protein should be of a high biological value. Protein moderation then helps reduce clinical signs but it
is not believed to affect progression (except potentially in proteinuric patients)
The NRC4 minimum protein requirement is around
16% protein calories, while AAFCO recommends maintenance feline diets provide at least 22%. Thus, protein intake will be adequate provided that the patient meets its energy needs. If the cat does not eat enough calories, muscle mobilization will happen and both
body and dietary protein will be used to obtain energy, resulting in protein:calorie malnutrition.
Feline CKD diets range from 22 to 34%, and all of them provide all amino acid requirements, thus there is a wide range to choose from for each specific case and adjusted to the stage of disease.
B vitamins & acid base balance
B vitamin losses can be increased due to polyuria, and inappetence can result in a decreased daily intake.
Kidneys are very important for acid base balance, and cats with CKD are prone to metabolic acidosis, which is why feline CKD diet are alkalinizing.
Omega 3 fatty acids
EPA and DHA have shown positive effects on experimental canine CKD, and one retrospective study in cats suggested that diets rich in these fatty acids could result in longer survival5.
Managing hydration
Cats with CKD are predisposed to dehydration, especially in IRIS stages 3 and 4. Studies confirming the clinical impact of maintaining hydration are lacking, but it is considered a critical part of management. Maintaining hydration may help maintain QOL, address electrolyte and acid-base disturbances, and preserve renal blood flow by
preventing dehydration (and potentially affecting disease progression). Unstable or decompensated cats with
CKD may require hospitalization and intravenous (IV) fluid therapy, along with management of electrolyte
and acid-base disturbances. Owners should also be educated about long-term management of hydration, including increasing voluntary water intake and home subcutaneous (SC) fluid therapy (75-150 mL every
1-3 days).6 Fluid choices include balanced electrolyte solutions or 0.45% saline. Potassium chloride can be added if needed to treat hypokalemia.
Managing nausea and inappetence
Cats with CKD may have nausea, vomiting, and inappetence because of uremic toxins affecting the central chemoreceptor trigger zone. Owners identify poor appetite as an important QOL concern; it could also result in protein and calorie malnutrition. A reduction in appetite should be actively investigated and treated;

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