Abstract Dilated cardiomyopathy (DCM) has been in the literature and news because of the recent opinion-based journal articles and public releases by regulatory agencies. DCM is commonly associated with a genetic predisposition in certain dog breeds and can also occur secondary to other diseases and nutritional deficiencies. Recent communications in veterinary journals have discussed a potential relationship between grain-free and/or novel protein diets to DCM, citing a subjective increase in DCM in dog breeds that are not known to have a genetic predisposition for the disease. This literature review describes clinical presentations of DCM, common sequelae, treatment and preventative measures, histopathologic features, and a discussion of the varied etiological origins of the disease. In addition, current literature limitations are addressed, in order to ascertain multiple variables leading to the development of DCM. Future studies are needed to evaluate one variable at a time and to minimize confounding variables and speculation. Furthermore, to prevent sampling bias with the current FDA reports, the veterinary community should be asked to provide information for all cases of DCM in dogs. This should include cases during the same time period, regardless of the practitioner’s proposed etiology, due to no definitive association between diets with specific characteristics, such as, but not limited to, grain-free diets and those containing legumes, novel protein diets, and those produced by small manufacturers to DCM in dogs. In summary, in order to determine if certain ingredients, categories of diets, or manufacturing processes are related to an increased risk of DCM, further studies investigating these variables are necessary.

An independent study was conducted to determine and quantify the oral care benefits of a daily edible dental chew in dogs as measured by plaque and calculus control, gingival indices, and oral malodor. A "clean mouth" test model was used comparing a commercial dry diet and a commercial dry diet plus one dental chew per day. The dental chew tested was representative of a retail canine dental chew. The test dental chew was a green-colored dental dog chew with a flexible texture that can be readily chewed by dogs. They are made with a knuckle bone shape on one end and a toothbrush shape on the other end. Sixty adult dogs were allocated in either control or test groups based on plaque stratification and studied for 28-days. The test group (30 dogs) received a dry diet and 1 dental chew each day. The control group (30 dogs) received the same dry diet only. At the end of the study, measurements of plaque and calculus accumulation and evaluations of oral malodor and gingival heath were performed. Adding a dental chew to the diet resulted in statistically significant reductions in plaque and calculus accumulation, and oral malodor while improving gingival indices.

Dilated cardiomyopathy (DCM) is considered a predominantly inherited disease in dogs. Recent reports suggest an increased incidence of DCM in atypical breeds eating grain-free and/or legume-rich diets. Emerging communications have noted that there is an apparent increase in the DCM incidence rate in the United States (US). However, little data regarding the incidence of DCM are currently available. To address the gap in the literature, this project examines the DCM incidence rate, over time, by retrospective polling of veterinary cardiologists across the US. Further, grain-free brick-and-mortar pet food market share data from 2011 to 2019 were presented. Fourteen US hospitals, out of 88 that were contacted to participate, provided all cardiology canine cases and of those, which specifically were diagnosed as DCM cases, for as many years as were available (1–20 years, average 8.1 years). This included a total of 68,297 canine patients evaluated by a cardiologist. Of the hospitals that participated, three provided age and breed data. A Poisson regression analysis revealed a statistically significant positive trend in the Mixed Breed group (P = 0.025, RC = 0.082), indicating that this group of dogs had an increased trend of DCM diagnoses over the past 15 years. However, there was no correlation (P = 0.16) for the Mixed Breed group and grain-free pet food sales data. The average incidence rate of DCM, amongst referral cases seen in the participating hospitals, was 3.90% (range 2.53–5.65%), while grain-free diet sales increased from 2011 to 2019. Nationally, the data did not support a significant change in percent DCM over time, from 2000 to 2019. There was no significant correlation between the national DCM incidence rate or the individual breed groups (P>0.05) in relation to the grain-free pet food sales. However, additional studies are necessary to understand whether regional factors contribute to increased DCM incidence rates within smaller cohorts.

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BackgroundDilated cardiomyopathy (DCM) is considered a predominantly inherited disease in dogs. Recent reports suggest an increased incidence of DCM in atypical breeds eating grain-free and/or legume-rich diets. However, little data regarding incidence of DCM within the US is available; and no existing data quantifies DCM among breeds over time.HypothesisWe hypothesized that DCM incidence among breeds could be estimated by retrospective polling of veterinary cardiologists. Further, if a correlation existed between grain-free diets and DCM, an increase in DCM would be on trend with increased grain-free pet food sales.Materials and MethodsThirty-six U.S. cardiology specialty practices were asked for all initial canine and DCM cases evaluated from 2000-2019; fourteen cardiology practices participated. DCM signalment data was provided by three hospitals over 15 years; representing 68 breeds. Age distribution of DCM cases upon diagnosis were compared to other cardio cases and general hospital population from one hospital. All data were evaluated using linear regression models. Grain-free pet food sales data was evaluated from 2011-2019.ResultsFourteen hospitals participated and reported 67,243 unique canine patients. Nationally, data did not support a significant change in percent DCM over time (p=0.85). The overall average incidence rate of DCM during the study period was 3.83% (range 2.41-5.65%), while grain-free diet sales increased 500% from 2011-2019. No correlation between overall DCM incidence and grain free diet sales was discovered. A significant upward trend in mixed breeds diagnosed with DCM, with no significant trend in other breeds was appreciated. An upward trend in age at DCM diagnosis was identified, correlating with trends from overall hospital populations.ConclusionsThese data do not support overall increased DCM incidence, or a correlation with grain-free pet food sales. Additional data are necessary to understand whether regional factors contribute to increased DCM within smaller cohorts.