Borderline kidney disease numbers caused by diet?

[10thomer]

Hi everyone! It's been about a year and I'm back with another confusing update...

As a quick summary, my now 6 y.o. boy Lewis had been suffering from frequent bouts of vomiting for a while and we were able to diagnose him with chronic pancreatitis. We switched him from Blue Buffalo wilderness mature chicken recipe grain-free to Tiki Cat Puka Puka Luau, which is very high protein and very low fat, because I believe the fat triggers his pancreatitis. He has not had any flair-ups since we switched foods.

What I remain confused about are his labs from over the years. He has no symptoms (i.e., increased thirst/urination, poor coat quality, weight loss, etc.) and an ultrasound performed last year shows that he has totally normal kidneys, but he's always had these borderline kidney results. The data from over the years is as follows:

12/27/19 (Lewis is 4 y.o.)
BUN: 25
CRE: 2.0
Phos: 3.9

12/17/20 (Lewis is 5 y.o.)
BUN: 26
CRE: 2.3
Phos: 4.7
SDMA: 15
Urine Specific Gravity: 1.019

(Pancreatitis was pretty bad around this time)

2/10/21 (Lewis is 5 y.o.)
BUN: 27
CRE: 2.6
Urine Specific Gravity: 1.030

3/19/21 (Lewis is 5 y.o.)
BUN: 25
CRE: 2.3

(We switch him from Blue Buffalo to Tiki Cat in between these readings)

1/14/22 (Lewis is 6 y.o.)
BUN: 38
CRE: 2.2
Phos: 4.3
SDMA: 14
Urine Specific Gravity: 1.024

(Reference ranges are: BUN 16-37mg/dL; CRE 0.9-2.5mg/dL; SDMA 0-14ug/dL; Phos 2-9-6.3 mg/dL)

I guess I'm just confused about how my young cat can have early CKD that has just... never progressed since he got his first blood test when he was 4 years old? His numbers fluctuate a bit, but they're generally pretty confusing (latest test shows normal SDMA but stage II kidney-level CRE... seems weird).

I'm just wondering if he actually doesn't have CKD and these results are just because he's on a high protein diet/wet food diet. Could definitely be wishful thinking, but I wonder if I switched him to a dry food diet (which he has essentially never been on in his life) that his values would look more "normal" since I presume these standards were set by mostly geriatric cats who have mostly been fed lower-quality dry food throughout their lives? Would love to hear your thoughts on this! I'm happy to provide more data if needed.

 

[fionasmom]

Effects of dietary protein content on renal parameters in normal cats - PubMed

Unfortunately, I am in a similar situation with Jamie, who is now 5. At 2 he had a suspicious blood test which showed high BUN and creatinine. We did an ultrasound, having been warned that something would be found, but nothing was....twice. He then progressed to HCM and was referred to a cardiologist. (Regular vet was banking on the fact that the HCM was causing the kidney readings.) Cardiologist does not feel that is the case after two EEGs. He was initially put on meds for the HCM but then taken off by the cardiologist who does not feel that his case is all that advanced, at least not yet.

He is difficult to reason with and wants what he wants. (Jamie, not the vet). I did manage to get him off of grain free which both of his vets feel affects cats with heart conditions as much as it does dogs. However, he does eat high protein food. He refuses all prescription food, which I am not sold on anyway, and other food which might be helpful. So here we sit.

After the second US on the kidneys, I was told that he would have kidney disease within two years. In his case, I do feel that something is going on with the kidneys, but it is certainly not resolved and he seems fine. His last BUN was 50, but his creatinine was normal. Then we introduce the question of dehydration. The vet who does the kidney US has a radiologist come in on a certain day, which means that all the animals have to wait their turn. My next move is probably going to be to ask for a referral to a hospital, possibly the one where the cardiologist is as they are up and running at all times, to see if that is a part of this conundrum.

 

[10thomer]

Effects of dietary protein content on renal parameters in normal cats - PubMed

Unfortunately, I am in a similar situation with Jamie, who is now 5. At 2 he had a suspicious blood test which showed high BUN and creatinine. We did an ultrasound, having been warned that something would be found, but nothing was....twice. He then progressed to HCM and was referred to a cardiologist. (Regular vet was banking on the fact that the HCM was causing the kidney readings.) Cardiologist does not feel that is the case after two EEGs. He was initially put on meds for the HCM but then taken off by the cardiologist who does not feel that his case is all that advanced, at least not yet.

He is difficult to reason with and wants what he wants. (Jamie, not the vet). I did manage to get him off of grain free which both of his vets feel affects cats with heart conditions as much as it does dogs. However, he does eat high protein food. He refuses all prescription food, which I am not sold on anyway, and other food which might be helpful. So here we sit.

After the second US on the kidneys, I was told that he would have kidney disease within two years. In his case, I do feel that something is going on with the kidneys, but it is certainly not resolved and he seems fine. His last BUN was 50, but his creatinine was normal. Then we introduce the question of dehydration. The vet who does the kidney US has a radiologist come in on a certain day, which means that all the animals have to wait their turn. My next move is probably going to be to ask for a referral to a hospital, possibly the one where the cardiologist is as they are up and running at all times, to see if that is a part of this conundrum.

Hmm this is really interesting and I'm sorry you're going through this with Jamie It's so stressful to not have a straightforward diagnosis with such young cats!!

A couple of questions for you:
1. What did they find on the second ultrasound that they didn't see in the first?
2. How long has it been since they've performed the second ultrasound?
3. What was Jamie's creatinine level?

 

[fionasmom]

They did not find anything on any ultrasound of the kidneys. I got ahead of my story. The fact that he would have kidney disease in the future appeared on an Antech report of about 10 months ago.

"The patient's status indicates that it will develop chronic kidney disease within the next 24 months with greater than 95% accuracy."

They also stated that they believed that there was a comorbidity/ underlying condition of cardiomyopathy which was contributing to the development of kidney disease. Other comorbidities were (Jamie does not have these) hyperthyroidism, diabetes, and hypertension.

Current creatinine is 2.1. For the most part, it reversed itself but the BUN has stayed high.

Last US of kidneys was last May.

 

[mrsgreenjeens]

10thomer , did your Vet tell you Lewis is in Stage II kidney disease? I've had three kidney cats and I'm just not really seeing it in the numbers you presented above. Particularly since you show what the lab shows are the reference ranges. Yes, this last time the BUN was one over the range, but everything else was within range, including the SDMA. One of my non-kidney cats recently had a UTI, at which time his kidney values went up, including SDMA, but once we got the infection under control, the numbers went back down. Another of my non-kidney cats has some numbers right at or right above the reference range, but his SDMA and Urine Specific Gravity are really good, and the his latest ultra sound showed no issues with his kidneys. My cats both eat a very high protein diet (mainly raw). What I'm getting at is unless your Vet said Lewis had kidney disease back when he was four years old, I'm thinking he didn't. Dehydration can cause creatinine to be higher, and even though a cat may eat wet food, they can still be slightly dehydrated during a Vet visit.

A side note, both of my current cats do have creatinine around 2.3, and our Vet knows I'm paranoid about kidney disease, but she has not said either of them have it even though if you go by the book this is considered stage II, as you stated. But I think you have to take ALL the numbers together (BUN, CRE, SDMA and USG) to come to that conclusion)

I would NOT consider switching Lewis's diet to dry food. I don't think feeding high protein food brings on kidney disease. And during early stages of kidney disease, it's not frowned upon to continue feeding high protein food. The new way of thinking among many Vets is that switching over to low protein foods may be what causes so many kidney cats to lose so much weight that they look like walking skeletons with fur Cats are obligate carnivores, which means they can exist on eating small animals alone (basically no carbs), and that in itself is a very high protein diet. IMHO, I feel that dry food can cause kidney disease, so I will never feed it again. My previous cats, the ones who did get kidney disease, had all been fed kibble most of their lives. A huge mistake on my part.

 

[10thomer]

10thomer , did your Vet tell you Lewis is in Stage II kidney disease? I've had three kidney cats and I'm just not really seeing it in the numbers you presented above. Particularly since you show what the lab shows are the reference ranges. Yes, this last time the BUN was one over the range, but everything else was within range, including the SDMA. One of my non-kidney cats recently had a UTI, at which time his kidney values went up, including SDMA, but once we got the infection under control, the numbers went back down. Another of my non-kidney cats has some numbers right at or right above the reference range, but his SDMA and Urine Specific Gravity are really good, and the his latest ultra sound showed no issues with his kidneys. My cats both eat a very high protein diet (mainly raw). What I'm getting at is unless your Vet said Lewis had kidney disease back when he was four years old, I'm thinking he didn't. Dehydration can cause creatinine to be higher, and even though a cat may eat wet food, they can still be slightly dehydrated during a Vet visit.

A side note, both of my current cats do have creatinine around 2.3, and our Vet knows I'm paranoid about kidney disease, but she has not said either of them have it even though if you go by the book this is considered stage II, as you stated. But I think you have to take ALL the numbers together (BUN, CRE, SDMA and USG) to come to that conclusion)

I would NOT consider switching Lewis's diet to dry food. I don't think feeding high protein food brings on kidney disease. And during early stages of kidney disease, it's not frowned upon to continue feeding high protein food. The new way of thinking among many Vets is that switching over to low protein foods may be what causes so many kidney cats to lose so much weight that they look like walking skeletons with fur Cats are obligate carnivores, which means they can exist on eating small animals alone (basically no carbs), and that in itself is a very high protein diet. IMHO, I feel that dry food can cause kidney disease, so I will never feed it again. My previous cats, the ones who did get kidney disease, had all been fed kibble most of their lives. A huge mistake on my part.

So my vet never said definitively one way or another if he has CKD, so today I point blank asked her "would you say that it's appropriate to diagnose him as a CKD cat" and her response was "no, not at this time". Which definitely makes me feel better but I'm still pretty freaked out that he just sits on the borderline with most of his tests.... like is it going to get worse or are these just his baseline numbers?

If Lewis had CKD, his super high protein diet and middle-of-the-road phosphorus food should have made him progress, but the only number that increased was his BUN but that makes sense because BUN is known to be really sensitive to changes in diet protein and dehydration. It was also so weird that his BUN was totally normal for over a year until I switched his food, then it shot up.

Out of curiosity, how long have your cats been at 2.3 for their creatinine? Also kind of strange that they would both have the same creatinine... makes me even more convinced it could be the diet making their numbers high rather than any underlying disease. I just really wish there were a different set of standard values for cats on a species-appropriate diet to avoid all of this confusion and anxiety..