Azodyl for Kidney Failure in Dogs–New Study Finds No Benefit

I have recently summarized the limited evidence concerning the use of Azodyl, a popular probiotic product, for treatment of kidney disease in cats, including a recent study presented as an abstract at the American College of Veterinary Internal Medicine Forum. Another study of this product has also been presented at the same conference.

David J. Polzin, DVM, PhD, DACVIM . Probiotic Therapy of Chronic Kidney Disease

This was a considerably more comprehensive research project, though still with some limitations, as is always true. 32 dogs with moderate kidney failure were randomly assigned to treatment with Azodyl or a placebo. They were otherwise treated identically according to a standardized algorithm for managing kidney disease. They were evaluated in terms of comprehensive bloodwork, body condition, and owner perception of quality of life and 7 time points from 1 month to 1 year after the start of the study. No significant difference in any measure was found between the groups at any time point.

The Azodyl was given as an intact capsule in this study, which eliminated the possible concern about the probiotic organisms being destroyed in the stomach that was raised in the cat study, in which the Azodyl capsules were opened and the product sprinkled on the food. The supplement was also given at twice the manufacturer’s recommended dose. Some of the dogs did have episodes of urinary tract infection during the 12 months of the study and did received short courses of antibiotics, which could potentially interfere with probiotic therapy. But this seems insufficient to entirely invalidate the rather startlingly consistent, negative findings of the study. And since infections are a common and unavoidable problem in kidney failure patients, if the therapy is so easily rendered useless, it would not be of much benefit in the even less controlled conditions of standard clinical use.

Of course, almost no single study should be taken as the final word on any therapy. However, negative results are likely to be more reliable than positive results, and the balance of the evidence is so far pretty negative concerning the usefulness of probiotic therapy for kidney failure. There are theoretical and in vitro study results which suggests that the best one could hope to achieve with probiotic therapy in kidney failure patients is a 10-20% decrease in bloodwork markers of renal failure, which might or might not be sufficient to meaningfully affect the clinical symptoms and the course of the disease. Certainly, in the face of being unable to routinely employ dialysis and transplantation, the most effective therapies available for humans with kidney disease, we should employ any treatment that offers a significant benefit, even a small one. But at this point, it doesn’t look like probiotic therapy holds especially great promise for this disease, unlike some of the other possible conditions in which it might be useful.

In any case, there doesn’t seem to be a strong case for suggesting owners spend their money on this product based on the evidence so far available. And the negative findings so far seen in clinical studies of dogs and cats point out the danger of extrapolating from limited studies in other species. The company-sponsored studies in rats and miniature pigs with artificially induced kidney disease have not proven an accurate indicator of the product’s performance in cats and dogs with naturally occurring kidney failure.

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116 Responses to Azodyl for Kidney Failure in Dogs–New Study Finds No Benefit

  1. skeptvet says:

    Of course, the first thing to remember is that there is no reason to believe Azodyl does anything useful at all, so that reduces any worries about how to give it. If there is a confirmed infection, then antibiotics are very important and should take precedence over unproven treatments. One can actually give probiotics and antibiotics together, and in fact the best proven use for probitoics is in reducing the risk of diarrhea caused by antibiotics, so that isn’t the issue so much as the lack of any evidence Azodyl is worth giving at all.

    Good luck!

  2. gwen b says:

    i can only say my dog is so healthy after i abandoned that all western medicine. she like all the others in the clinic was given death sentence but those under doc marga who chose to introduce five leaf pet pharmacy r doing well. we still do subq the western med aspect n homeo for her heart but when the sitter made a mistake in prescribing the azodyl her blood test changed for the worse. i gave my dog blood test so often so its documented. i went thru trial n error n spent so much money. n happy. there is no specific combination cause each to his own. you hv to be as willing as me to spend to declare what worked for ur dog. the vet is sceptical as always re homeo but remains amazed in cookie one of a kind recovery. i really feel sorry for the others who dont know this option so i shared mine so they can try rather than see their baby die.

  3. gwen b says:

    Science may prove few things thru so called data collection but it hasnt cured everything. nobody wants to do research for alternative meds because they aint as rich as pharmaceutical cos who fund researchs that benefit their sales. the best is combination of both world. my dog from death sentence changed dramatically with the alternative combined with science proven method like fluid therapy. azodyl is really life saving.. we run out cause hospital runs out n that sends her numbers. if thats not data what is

    the beauty of this generation is we get to hear others experience. we get to hear things the pharmaceutical companies have been hiding from us. at the end the winner is someone who beat the odds. n its usually someone who took advice from east n west school of thinking.

    im just curious do u hv a pet that has crf..did it survive with just these meds n subq n those processed foods. if u do u will be more convincing.

  4. Andy G says:

    Our 11 yr old Yorkie/Silky mix was lethargic, losing weight, and leaking urine about 2 moths ago. Took her to the vet within a week of symptoms. She had a UTI, and blood tests showed she had kidney disease. Prognosis was, if untreated, she had 3 to 6 months. Vet recommended strict kidney diet, epiakitin, and azodyl as per manufacturer directions. We immediately stopped all hi protien food and treats and started feeding Hills Prescription Diet Kidney Care K/D w/chicken canned food and Hills P D Kidney Care K/D dry kibble, and treats, along with directed dosages of the Azodyl and Epakitin. She has gained all her weight back, and her blood test last week showed all her kidney numbers were greatly improved. And she’s back to her old self, the toughest 12# Yorkie around. Vet was thrilled and said she now has 3 to 5 years left (clost to a normal life span) instead of only 3 to 6 months! We are thrilled also. Her diet/ supplement is relatively expensive, but we will not change anything! We have our Sissy back!

  5. skeptvet says:

    It’s great that your dog is doing so well, but of course it likely has nothing to do with the Azodyl and everything to do with all of the other, proven medical treatments you are using (antibiotics for the UTI, a renal diet, a phosphate binder, etc.).

  6. Monica says:

    Five leaf pet pharmacy? My dog is in kidney failure. What exactly do you give your dog?

  7. Carol Jander says:

    Renadyl is same as Azodyl only more CFU’s. It is also sold for animals, but much lower price and stable.

  8. Ella Washington says:

    I’m a touch mystified that you claim these to be rigorous scientific results – never published (of course you can publish negative results, because they can be quite valuable), seen only as a non-reviewed abstract without details of methodology. I’m not saying the results are wrong or can not be reproduced. I am saying the “results” as presented are on a par with anecdotal evidence – we know essentially nothing about them and can draw no conclusions. Thanks. PhD biochemistry here.

  9. skeptvet says:

    And, of course, research has failed to show any benefit to Renadyl just as it has failed to show benefit to azodyl.

  10. skeptvet says:

    I never called these “rigorous scientific results,” so that’s a straw man. I described the study as “a considerably more comprehensive research project [than the previous study I discussed], though still with some limitations, as is always true.” I also said, “Of course, almost no single study should be taken as the final word on any therapy. However, negative results are likely to be more reliable than positive results, and the balance of the evidence is so far pretty negative concerning the usefulness of probiotic therapy for kidney failure.”

    The point is that the claims made for these products are entirely without supporting clinical trial evidence, and the limited evidence that does exist, in dogs, humans, and cats, all fails to show a benefit. The most reasonable conclusion based on the existing data, is that these products don’t do much if anything. Like any conclusion in science, this may be altered by additional evidence, but right now companies are making millions fo dollars selling people products like this despite not having shown they do anything. It puzzles me why you seem more bothered by my preferring this level of evidence to anecdote than by the fact that these products are marketed without any reason to think they do anything.

  11. Ella Washington says:

    I came looking for info on Azodyl today because I heard a vet office cat was put on it to decrease urination in a just-above-normal kidney values cat. Apparently, the cat went from urinating over 10 times a day to 2 or 3, in the space of a few days, and I was surprised. The vets clearly weren’t, so I wanted to learn more. It’s quite true that there seems to be no clinical data about Azodyl. But you cite a “study” that’s less rigorous than a high school science project as “existing data” and “limited evidence” and refer to “conclusions in science” when none exists here. Peer-reviewed work, that’s scientific data. Describing methodology, reproducible, published in reputable journals, yes. My conclusion here is that there is NO published data on Azodyl, positive or negative, unless my vets have a source I’m not finding online. So, all I know about is one office cat with a very positive response. As a scientist, I can’t draw any conclusions at all and am surprised that you feel you can.

  12. skeptvet says:

    Sorry, but if you think scientific evidence consists of perfect RCTs or nothing, then you don’t understand critical appraisal or evidence-based medicine very well. An abstract is less reliable than a peer-reviewed RCT and more reliable than anecdote, so saying there is “NO evidence” is simply wrong. We don’t simply throw up our hands and refuse to make decisions in thee absence of perfect evidence. Perhaps as a chemist, you have that luxury, but as a clinician I do not. I have to decide whether to use or not use, recommend or not recommend, therapies based on the evidence that exists, not the evidence I wish existed.

    Azodyl is fundamentally implausible, it has failed in clinical trials in humans, and it has failed in preliminary trials in dogs an cats. When my clients ask whether or not they should use it, it is unethical for me to say “I have no opinion,” and I must say, “There is limited evidence and what exists does not suggest any benefit.”

  13. Diana says:

    This is an example why you need to do research and trust your gut when it comes to your pets. I know this post is old but now research is that in fact NO renal diets are not beneficial and actually harm the cat more. Cats need meat, high quality proteins.

    I agree with other users above homeopathy will always be put down but pharma because they can and do work in some cases

  14. skeptvet says:

    First of all, “Di research and trust your gut” just means believe whatever you want and selectively seek information that supports those beliefs.

    Secondly, feel free to cite any research, because your claim is not consistent with the evidence.

    Proc Nutr Soc. 2016 Aug;75(3):392-7. doi: 10.1017/S002966511600029X. Epub 2016 Jun 8.
    Veterinary clinical nutrition: success stories: an overview.

    Davies M1.
    Author information
    School of Veterinary Medicine and Science,University of Nottingham,Sutton Bonington Campus,Loughborough LE12 5RD,UK.
    In this overview of success stories in veterinary clinical nutrition topics in cats and dogs reviewed include the dietary management of chronic kidney disease, dissolution of urinary tract uroliths by dietary modification, the recognition that taurine and L-carnitine deficiencies can cause dilated cardiomyopathy; that clinical signs associated with feline hyperthyroidism (caused by a benign adenoma) can be controlled by a low-iodine diet alone; that dietary management of canine osteoarthritis can also reduce non-steroidal anti-inflammatory drug doses; and that disease-free intervals and survival times can be statistically longer in dogs with Stage III lymphoma managed with diet. As we discover more about nutrigenetics and nutrigenomics, and as we expand our basic understanding of idiopathic diseases we are bound to identify more nutritionally related causes, and be able to develop novel dietary strategies to manage disease processes, including the formulation of diets designed to alter gene expression to obtain beneficial clinical outcomes.

    Geddes RF, Elliott J, Syme HM. The effect of feeding a renal diet on plasma fibroblast growth factor 23 concentrations in cats with stable azotemic chronic kidney disease. J Vet Intern Med. 2013;27:1354–1361.
    Fibroblast growth factor 23 (FGF-23) is a phosphatonin, which is increased in cats with azotemic CKD. Dietary phosphate restriction decreases FGF-23 concentrations in humans and rodents, but this relationship has not previously been examined in the cat.
    To investigate the effect of feeding renal diet on plasma FGF-23 concentrations in cats with stable azotemic CKD.
    Azotemic, client-owned cats (? 9 years); 33 cats ate renal diet (RD group) and 11 cats did not eat renal diet (comparator group) over 28-56 days.
    Retrospective longitudinal study: Plasma FGF-23, PTH, and phosphate concentrations were measured at baseline and after 28-56 days. Cats in the RD group were classified as hyperphosphatemic (HP) or normophosphatemic (NP) based on the International Renal Interest Society targets for plasma phosphate concentration. Nonparametric tests were performed.
    In the HP group (n = 15), feeding renal diet was associated with a significant decrease in plasma phosphate (P = .001), PTH (P = .007), and FGF-23 (P = .008), but not creatinine concentrations (P = .91). In the NP group (n = 18), feeding renal diet was associated with a significant decrease in plasma FGF-23 (P = .006), but not phosphate (P = .48), PTH (P = .35), or creatinine concentrations (P = .10). No significant changes were seen in any parameters in the comparator group during the study period.
    Feeding renal diet is associated with reductions in plasma FGF-23 concentrations in hyper- and normophosphatemic cats with stable azotemic CKD, suggesting that dietary phosphate restriction may enable cats with CKD to maintain normal plasma phosphate concentrations in association with lower plasma FGF-23 concentrations.

    Ross SJ, Osborne CA, Kirk CA, et al. Clinical evaluation of dietary modification for treatment of spontaneous chronic kidney disease in cats. J Am Vet Med Assoc. 2006; 229:949–957.
    Objective-To determine whether a renal diet modified in protein, phosphorus, sodium, and lipid content was superior to an adult maintenance diet in minimizing uremic episodes and mortality rate in cats with stage 2 or 3 chronic kidney disease (CKD). Design-Double-masked, randomized, controlled clinical trial. Animals-45 client-owned cats with spontaneous stage 2 or 3 CKD. Procedures-Cats were randomly assigned to an adult maintenance diet (n = 23 cats) or a renal diet (22) and evaluated trimonthly for up to 24 months. Efficacy of the renal diet, compared with the maintenance diet, in minimizing uremia, renal-related deaths, and all causes of death was evaluated. Results-Serum urea nitrogen concentrations were significantly lower and blood bicarbonate concentrations were significantly higher in the renal diet group at baseline and during the 12- and 24-month intervals. Significant differences were not detected in body weight; Hct; urine protein-to-creatinine ratio; and serum creatinine, potassium, calcium, and parathyroid hormone concentrations. A significantly greater percentage of cats fed the maintenance diet had uremic episodes (26%), compared with cats fed the renal diet (0%). A significant reduction in renal-related deaths but not all causes of death was detected in cats fed the renal diet. Conclusions and Clinical Relevance-The renal diet evaluated in this study was superior to an adult maintenance diet in minimizing uremic episodes and renalrelated deaths in cats with spontaneous stage 2 or 3 CKD.

    Elliott J, Rawlings JM, Markwell PJ, et al. Survival of cats with naturally occurring chronic renal failure: effect of dietary management. J Small Anim Pract. 2000;41:235–242.
    Fifty cats with naturally occurring stable chronic renal failure (CRF) were entered into a prospective study on the effect of feeding a veterinary diet restricted in phosphorus and protein with or without an intestinal phosphate binding agent on their survival from initial diagnosis. Twenty-nine cats accepted the veterinary diet, whereas compliance (due to limited intake by the cats or owner resistance to diet change) was not achieved in the remaining 21. At diagnosis, both groups of cats were matched in terms of age, bodyweight, plasma creatinine, phosphate, potassium and parathyroid hormone (PTH) concentrations, packed cell volume and urine specific gravity. Feeding the veterinary diet was associated with a reduction in plasma phosphate and urea concentrations and prevented the increase in plasma PTH concentrations seen in cats not receiving the diet. Cats fed the veterinary diet survived for longer when compared with those that were not (median survival times of 633 versus 264 days). These data suggest that feeding a diet specifically formulated to meet the needs of cats with CRF, together with phosphate binding drugs if required, controls hyperphosphataemia and secondary renal hyperparathyroidism, and is associated with an increased survival time.

    Thirdly, homeopathy is nothing but a placebo.

  15. Elizabeth Dickinson says:

    My vet recommended Azodyl today so it must be working since it’s been on the market for so long. We’re using it in conjunction with prescription food. I trust my vet.

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