Sunday, October 25, 2020

FDA Quietly Issues 2020 Update on diet-associated DCM at Kansas State Forum

    09/29/2020, Kansas State held a virtual forum where stakeholders and researchers presented on the topic of Dilated Cardiomyopathy and diet. Speakers included industry members, veterinary researchers, and members of the FDA. On 10/16/2020, Kansas State distributed the materials online

    Perhaps most noteworthy in the materials is an update from the FDA, though their website has remained quiet since the July 2019 release. In the opening remarks to the forum, FDA's Dr. Steven Solomon says "We have tried to be careful in our messaging, and we recognize going forward not to speak on this topic publicly unless we are clarifying information or have something substantive to share. As I have said on numerous occasions, we are not looking to put out any additional information until we have more scientific certainty. ... Although CVM’s investigation must be driven by science and our public health mission, we are acutely aware that promoting transparency and public awareness may not be kind to everyone’s bottom line. I empathize with those of you who have experienced adverse consequences in your businesses, and with those of you in the veterinary community who have had your own challenges in sharing your scientific findings and trying to determine what type of diets to recommend to your clients and their pets."

What's important for pet owners to know is that these findings continue to support that there is a link between certain diets and the development of dilated cardiomyopathy.

The report is now publicly available, and the FDA is reportedly in the works of determining how to most effectively communicate updates on their findings to the public. In the meantime, and in the interest of transparency, here are the highlights of what was provided at the forum:

  • As of 07/20/2020, the FDA has received over 1100 reports of DCM
  • Clinical information has been collected by Vet-LIRN for 161 dogs in order to track and characterize their recovery. Group One represents 121 of the dogs reported between 1/2018 and 8/2019. 107 of those dogs (88%) have had a full or partial recovery. 
    • 23 (19%) fully recovered, 84 (69%) partially recovered
    • All dogs that recovered received a change in diet, and the majority also received taurine, a dietary supplement, and pimobendan, a drug that slows, but does not reverse, cardiac disease. 
    • Recovery time for fully recovered dogs ranged from 6-12 months, with a few dogs taking 2 years
    • Dogs that presented with severely low taurine recovered more than dogs presented with slightly low, normal, or high taurine
  • Group Two represents 40 of the dogs reported between 11/2019 and 7/2020 and is preliminary data
    • 30 (75%)dogs have recovered partially and 5 (12%) have recovered fully
    • Trends aligned with Group One
  • Taken directly from the FDA materials on diet at time of diagnosis:
    • "For fully and partially recovered cases on a case-based evaluation, of the 107 fully and partially recovered cases: 
    • 2 of the 107 cases did not have enough information to determine grain or grain-free exposure status, and 4 of the 107 did not have enough information to determine pulse exposure status.
    • 98 of 105 (93% of cases) ate grain-free foods.
    • 90% (95 of the 105 cases) only ate grain-free foods.
    • Of the 7 that ate grain-containing foods without eating grain-free foods: 
    • 4 of the 7 ate a vegan diet with whole peas as the first ingredient. 
    • 2 of 7 ate chicken or lamb and rice diets containing split peas. 
    • 1 of 7 ate lamb meal and rice. 
    • 97% of cases (100/103) were exposed to whole pulse ingredients in their diets.
    • 0% of cases were exposed to diets with meat by-products or poultry by-products."
  • Taken directly from the FDA materials on diet fed during recovery:
  • "For Group One fully recovered cases – Recovery diets, on a PRODUCT basis: 
    • 96% of the reported diets fed in the recovery period are grain-containing, although 3 were “hydrolyzed protein” diets – 2 with corn starch, 1 with brewer’s rice. For this analysis, I considered corn starch a grain (or grain derivative), although it was harder to categorize. Brewer’s rice is a grain. 
    • Only 8% of reported recovery diets had peas in the top ingredients, 4% had whole peas, and none had lentils.
    • Animal-source proteins: 42% of the recovery diets contained meat by-products or poultry by-products (primarily poultry by-products).
    • 8% of the recovery diets had lamb meal, whereas 34% had lamb meal in the before diagnosis phase."

    Recovery seen with a change in diet is consistent with an underlying dietary etiology to these cases. Secondary DCM is only known to resolve when the underlying cause is addressed, and the additional therapeutic measures (pimobendan and ACE inhibitors) have not been documented to reverse cardiac disease, only stabilize patients, slow disease progression, and prolong patient survival. These findings further support that some aspect of legume-rich, grain-free diets contributes to the development of dilated cardiomyopathy and underscore the need for continued research. 

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8 comments:

  1. Thank you for posting this update! You rock!

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  2. I'd be careful with the statement "pimobendan has not been shown to reverse cardiac disease". PDE3I's have been well documented to reduce LAP as well as LV and LA sizes in dogs. Additionally, the use of LVIDdN is inappropriate as an indicator of systolic function, as referenced in the CVCA presentation. Rather, LVIDsN should be utilized. In reality, all linear measurements are likely not adequate indicators of cardiac function, and assessment should be performed volumetrically, as is the standard in human medicine. Finally, taurine is known to be a positive intotrope and thus attributing improvement in cardiac dimensions to diet alone in patients that have both a diet change as well as taurine supplementation is inappropriate, as the taurine supplementation introduces a confounding variable. Just food for thought.

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    1. I appreciate the input! I’m certainly not a cardiologist, but I’m doing my best to ensure that what I write is informed by expert opinion and evidence-based statements. I’m not sure what your background is, as you commented anonymously. You’re welcome to stay anonymous if you’re most comfortable that way, but I would also love to know who I’m engaging with!

      I understand the desire to use volumetric methods to assess cardiac function, as is standard human-side like you mention. However, I believe that making such a transition in veterinary medicine has been complicated by the lack of repeatability across institutions? In the case of discussing large amounts of data from multiple centers, it seems hard to ignore improvements in the more reproducible, linear measurements. The closest thing to a standardized approach to diagnosing DCM in dogs that I’m aware of is the 2003 Proposed Guidelines from ESVC (https://doi.org/10.1016/S1760-2734(06)70047-9) These guidelines describe utilizing fractional shortening as an indicator of systolic function and utilizing left ventricular internal dimension in systole or diastole to identify dilation.

      In regards to pimobendan: this may be a matter of semantics, splitting hairs over what defines disease reversal. As far as I’m aware, administration of pimobendan has not resulted in complete discontinuation of medical therapy for CHF in any published clinical trials. The outcomes of dogs on pimobendan in clinical trials do not suggest that DCM improves to such a degree that medical therapy will be stopped or echocardiographic measures will normalize. Reduction of LAP and LV and LA sizes is not the same as a complete resolution of clinical signs and echocardiographic evidence of cardiomyopathy, the latter of which is being reported in the cases in question. In my statement, what I intended to convey is that pimobendan does not “cure” DCM, and yet dogs in cases reported to the FDA are showing a complete recovery from the disease. It is unlikely attributable to the administration of pimobendan as a primary factor. I can revisit my phrasing to try and remedy that potential point of confusion, if you think it warranted.

      Taurine is, generally speaking, documented to produce a positive inotropic effect, but if I’m not mistaken, it isn’t considered standard of care for DCM of genetic origin. If such a benign supplement had a marked substantial effect on improving systolic function in dogs, I would expect that it would be included more commonly in treatment regimens. As I understand right now, there is no data that documents a positive inotropic response in dogs with DCM supplemented with taurine alone, in the absence of a taurine deficiency. While taurine may improve some parameters, and dogs with DCM may benefit clinically from administration, much like pimobendan, it does not “cure” DCM (unless the DCM is secondary to taurine deficiency).

      To pull this all together… administration of medical therapies like pimobendan and taurine alongside a diet change can be confounding variables, but they also appear to be unlikely contenders for standing alone as explanations for the observed disease resolution. I don’t believe that the presence of these variables invalidates or undermines the importance of this disease or the role of diet in the etiology of this disease.

      I’m open to discussing this further. If you have additional comments or would like to add some literature to the conversation, please feel free to continue here or reach out via email to info@docofalltrades.net

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  3. Here is a study where dogs were weaned off of heart medications...https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1939-1676.1997.tb00092.x

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    1. Thanks for sharing! That study shows that in dogs with DCM secondary to taurine-deficiency, specifically, ACSs with DCM, supplementation with taurine +/- carnitine can result in a complete or partial reversal of the disease, including discontinuation of cardiac medications. This is consistent both with the statement in the article " Secondary DCM is only known to resolve when the underlying cause is addressed," and my statement in an earlier comment you may have read, "[taurine] does not “cure” DCM (unless the DCM is secondary to taurine deficiency)."

      Taurine-deficiency is a well-documented cause of secondary DCM, first noted in cats and later documented in some dog breeds, such as American Cocker Spaniels in the study you supplied. Taurine-deficiency can occur secondary to nutrition alone (https://avmajournals.avma.org/doi/10.2460/ajvr.2001.62.1616) and improvement of disease with taurine supplementation further suggests an underlying dietary cause, rather than precluding it, particularly given the other pertinent information in these cases (variety of breeds, similiarities in diet characteristics of affected dogs, etc). Of course, not all dogs that the FDA is receiving reports of are taurine-deficient. Based on the most recent presentation, taurine-deficiency at presentation does appear to be a prognostic factor.

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  4. We need clarity in terminology. "Grain Free" is not defined anywhere. If a diet is primarily meat v primarily pea starch or potato mash it is still called grain free ad these could not be more different nutritionally.

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    1. Thanks for commenting! When a diet is referred to as "grain-free," that just means that it does not contain corn, wheat, rice, barley or other grains. Like you point out, 'grain-free' does not provide any additional details about the formulation (such as amount of meat vs amount of plant protein, macronutrient spread, or micronutrient concentrations). From the data the FDA released in 2019, 91% of the reports involved diets labeled 'grain-free,' 93% involved diets with peas or lentils, and 89% involved diets with peas. This is imperfect information, but it does provide a starting point for further investigation.

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