Kidney Diets - When are they necessary?

daniel625

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~Warning, this post is a bit of a rant, so please bear with me~

Okay, HELP!  Half of the sites I've read either veterinary-related or from people who have had cats with CKD, as well as other vets I have talked to, have said that there are different stages of Kidney Disease in cats and that Kidney diets are only necessary when it gets to a certain level (i.e. stage 3) as giving it to them at too early of a stage can backfire.  While others (i.e. my family) say that there are no "stages" of Kidney Disease, it's either non-existent or full-blown and that a kidney diet should be fine to arbitrarily give to an older, but otherwise healthy, non-CKD cat "just because they are older".

I'm convinced that my cat, who may have had early CKD, lost a whole pound because he ate kidney food at too early of a stage, while my vet and my family (with no medical backgrounds or without doing any research of their own) have been trying to convince me that this was either the disease progressing or a total coincidence and nothing more.  All I know is when my cat was eating his regular diet, his weight was much better, but then he eats the kidney diet and he becomes bony.

Both sides are convinced beyond a shadow of a doubt that they are 100% correct, so I need a tie-breaker here.  Who is right and who is wrong?

~end ranty post~
 
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1CatOverTheLine

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The "stages" are based on creatinine levels, because as a general rule that's the simplest indicator of kidney function.  A creatinine level of less than 1.6 - but with other symptomatic indicators, such as low electrolytes, dilute urine, or excess protein in the urine, suggests slightly diminished kidney function, and is generally called "Stage 1."  Creatinine levels between 1.6 and 3.0 (and especially in the presence of secondary hypertension), suggests that kidney function has diminished to between one-third and one-quarter of normal (25% is approximately the minimum kidney function to effectively filter toxins), and is called, "Stage 2."  A Creatinine level between 3.0 and 6.0 - especially in the presence of abnormal electrolytes - is generally an indicator that kidney function has dropped below 25%, and that the kidneys are no longer functioning with sufficient efficacy to perform their task, and is called, "Stage 3."  Most modern texts also cite Creatinine levels in excess of 6.0 being, "Stage 4," or End Stage.

Peritoneal dialysis (or even hemodialysis, for that matter) is an option as renal failure progresses, as is transplant surgery (the University of California [Davis Veterinary Medicine School] program currently indicates a success rate of 75 - 80% for feline kidney transplant patients), depending upon the cat's age and overall health, and transplantation is being used increasingly for cats with acute renal failure stemming from ingesting antifreeze and other toxins.

When to begin a special diet is up to the individual veterinarian, and is usually based on a full blood panel in addition to a simple serum Creatinine level test.

.
 
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mrsgreenjeens

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I've had 3 cats with kidney disease, and they have all lost muscle mass because of not eating, or not eating enough protein.  By the third cat we finally convinced out Vet that eating low protein probably was NOT good for our furbaby, and she agreed!  She said the new way of thinking (per a Vet convention she had just attended) was to have them continue to eat good, high protein food until they reached a certain point in the kidney disease, which is around Stage 3.  There most definitely ARE stages in feline kidney disease, as stated above, although my "go to" website that breaks it all down might have slightly different figures for the stages.  Here is the website I refer to whenever I have a CRF question:  http://www.felinecrf.org/how_bad_is_it.htm

Kidney food is lower protein, and cats needs protein.  When kidneys get too bad off, they cannot process the protein very well, therefore, in later stages, it's better to have less protein in the food, but the downside is, lower protein causes muscle loss
 

lisamarie12

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I had two cats with CKD years ago. The new school of thought is not to restrict protein in the diet of an obligate carnivore until they are near end stage renal failure. Otherwise, it's phosphorus that can be lowered but still maintaining a high quality protein diet.

There are quite a few of Weruva canned foods that are lower in phosphorus, below 1% on a dry matter basis, as well as low sodium. For raw fed cats, a diet that utilizes eggshell for calcium vs bone, like Rad Cat, can be appropriate for some CKD cats.

If a CKD cat won't eat a lower phosphorus food, a phosphorus binder can be prescribed by the vet, this gets mixed into the food and lowers the phosphorus %.
 

white shadow

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Hi Daniel625 .

I just now caught your post.

For a fuller understanding of the nutritional requirements of cats with reduced kidney function, I think this would be the best place to start: http://www.felinecrf.org/nutritional_requirements.htm#protein

Once you've 'digested'
that section, try going to the top of that page and see if the broader picture helps 'place' what you've read into perspective.

And.......from my hearing and reading peoples' experiences.........it's no 'coincidence', nor probable 'disease progression' behind that weight loss.....it's inadequate nutrition!

(IMO, the very best online support/advice/info for "kidney cats" is to be found in the specialized online community sponsored by the author of that referenced website.....for info this FAQ page has it all: http://www.felinecrf.org/tanyas_support_group.htm .........the group itself is here: https://tanyackd.groups.io/g/support )

'Hope that will help !
 
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daniel625

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Thanks for the replies!

I'm actually quite familiar with the Tanya CRF site and paid it a visit quite a few times.  While there were some things on it that I didn't quite agree with (i.e. dry food never being good nor having anything to do with good dental care, etc.), a lot of it was pretty comprehensible information that made sense.

I'm just glad to get confirmation that there ARE stages and that restriction of protein should not be an arbitrary decision based on age alone.  These are assumptions that a lot of people I know seem to make, and I feel kinda weird knowing that I know more than them about this matter.

I think it's safe to say that I will be taking my future cat to a different vet, as the one I had been going to was right about some things but seemed really out of touch with a lot of other things (see my original post).

If I may ask a follow-up question, what is the average amount of time it takes to go from Stage 2 to end stage?

A year, two years, months, weeks, or is it completely random?
 

1CatOverTheLine

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daniel625

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Thanks for the link.

Hmm... well based on what I just read, it seems like my vet should have prescribed Azodyl instead of Epakitin, since the former is said to address BUN count, which was high in my cat, while Epakitin deals more with phosphorous, which was still perfect when first suggested to me.

My cat didn't have hyperthyroidism (surprisingly), heart rate, teeth, gums, and lungs were perfect, he did have urinary tract crystals and stones for a while, but had long since been successfully dissolved and never had diarrhea or peed/pooped outside of  the box.  In the end, no crystals or stones, but the big three (BUN, Creatinine, and Phosphorous) were all elevated.  What's weird though is that the month before kitty died, a different veterinarian in the same office checked on him and said that his kidneys felt fine, not too big or small or hard.

The only symptoms I could see were excessive drinking from the sink, sometimes not finishing or barely touching his food (while on other days, he'd devour it) and feeling really relieved whenever pressure was applied to his lower back (where the kidneys are?).  But he was still pretty responsive for a geriatric and still capable of running around and jumping up on things.

What the hey!?
 
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mrsgreenjeens

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I'e had three kidney cats, and in the end, they all three had raised BUN and Creatinine, but nothing else particularly out of what, with the exception of their Urine Specific Gravity.  My last one could still jump up on the kitchen counters...no arthritis or such until the day she died, when suddenly she woke up with her hind end paralyzed, which was completely unrelated to her kidney issues.  She also never ever needed a dental in her life, and she lived to be 16 years old.  My previous kidney cat had horrible teeth and needed several dentals, but no other health issues other than his kidneys.  He also lived to be 16.   None of  my cats were ever given Phos Binders (Epakitin or anything similar) because they didn't need them from assessing their bloodwork).  They ALL needed sub-q fluids, however, once they reached a certain stage.  This, and pepcid A/C, helped quite a bit. 

Azodyl is not a "drug", so many Vets may not recommend it.  And it's pretty hard to dose, from what I've heard from some people.   You don't need a prescription for it . 

I honesty don't remember how long our first kidney cat lived once he was diagnosed, but the other two both lived 3 years after diagnosis, and were both probably already in Stage 2 at that time.   
 

sweetpea24

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~Warning, this post is a bit of a rant, so please bear with me~
Okay, HELP!  Half of the sites I've read either veterinary-related or from people who have had cats with CKD, as well as other vets I have talked to, have said that there are different stages of Kidney Disease in cats and that Kidney diets are only necessary when it gets to a certain level (i.e. stage 3) as giving it to them at too early of a stage can backfire.  While others (i.e. my family) say that there are no "stages" of Kidney Disease, it's either non-existent or full-blown and that a kidney diet should be fine to arbitrarily give to an older, but otherwise healthy, non-CKD cat "just because they are older".

I'm convinced that my cat, who may have had early CKD, lost a whole pound because he ate kidney food at too early of a stage, while my vet and my family (with no medical backgrounds or without doing any research of their own) have been trying to convince me that this was either the disease progressing or a total coincidence and nothing more.  All I know is when my cat was eating his regular diet, his weight was much better, but then he eats the kidney diet and he becomes bony.

Both sides are convinced beyond a shadow of a doubt that they are 100% correct, so I need a tie-breaker here.  Who is right and who is wrong?
~end ranty post~
If you go by IRIS staging, a kidney diet is recommended at stage 1 through 4. These diets have controlled protein and phosphorous levels as well as Omega fatty acids which have been shown to help increase glomerular filtration and to reduce inflammation. OFA's also help reduce muscle wasting due to CKD and aging.The new Hills k/d feline diet now has carnitine which has been shown to help with protein and fat metabolism and thus sparing oxidation of amino acids for energy metabolism that are used for protein synthesis. This increases lean body mass, decreases catabolism (where the body essentially eats its muscle). Research suggests that carnitine improves mitochondrial function as a result and CKD animals had more energy. Excess carnitine is excreted through the kidneys thereby conserved by reabsorption. This new formula of k/d also has higher palability. Hills is also coming out with k/d and mobility diet that addresses the needs of CKD pets with arthritis and degenerative joint disease. This new k/d also provided higher calories in a smaller amount of food so CKD patients meet their caloric requirements which is vital in CKD. I sound like an advertisement but really, this sounds promising. Plus renal diets have been shown to extend the lifespan and quality of life of CKD pets by an average of three years. And it's important to know that the protein in these foods aren't deficient; it is controlled. The NRC recommends 5 g protein per 100 kcal and the AAFCO recommends 6.5 g protein per 100 kcal. K/d provides a little more than the AAFCO recommendation. Keep in mind excess protein gets excreted by the kidneys which causes stress and inflammation which is not what you want. Plus, high protein means phosphorous. The quality of the protein is important as well. If the protein isn't digestible, or in other words, bioavailable to the cat's body, then there really is no point and again, this unused protein will cause unnecessary stress on the kidneys. Renal diets like k/d go through digestibility trials, unlike over the counter diets. In K/d for example, the protein is 95% digestible. I am not a big fan of the ingredients in veterinary diets but in the end, it is the nutrients that count.
 
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