A recent study conducted by veterinarians and scientists from BSM Partners, the leading pet care research and consulting firm, in collaboration with the University of Missouri, has shed new light on the potential link between canine dilated cardiomyopathy (DCM) and grain-free dog food. Published in the peer-reviewed journal Frontiers in Animal Science, this analysis was based on a retrospective survey that examined the annual incidence of DCM diagnoses made by veterinary cardiologists throughout the United States. Additionally, the study investigated the sales growth of grain-free pet food stores.
Dilated cardiomyopathy (DCM) is a common heart condition in dogs, causing reduced heart function and enlargement of heart chambers, often leading to heart failure, arrhythmias, and sudden death. While previously associated mainly with specific breeds, recent studies have identified DCM in various other breeds. The incidence of DCM in the past has been reported, but not its annual rates over time or diagnoses by veterinary cardiologists across the United States. This is crucial, especially considering recent concerns linking certain diets, particularly grain-free diets high in pulse ingredients, to DCM development in dogs. Some affected dogs improved when their diet was changed, raising suspicions about a dietary factor in DCM cases. Therefore, understanding the frequency of DCM diagnoses in the US over the last decade is essential in addressing these concerns.
The aim of the study was to examine the yearly occurrence of DCM diagnoses made by veterinary cardiologists, track changes over time, and assess the age and breed demographics of DCM patients. Furthermore, the study sought to gather sales data for brick-and-mortar grain-free diets between 2011 and 2019 and then correlate this information with the annual incidence of DCM to explore potential relationships.
The study utilized a retrospective approach to analyze DCM incidence in dogs diagnosed by veterinary cardiologists from 2000 to 2019. It involved contacting 88 referral institutions, including accredited veterinary colleges and private referral hospitals, with active veterinary cardiologists. Fourteen of these institutions participated in the DCM survey, with three providing additional breed and age distribution data.
To be included as a DCM case, the diagnosis had to come from a board-certified veterinary cardiologist or a supervised cardiology resident. Data were collected on the annual number of initial canine cardiology cases and the number of cases with an initial DCM diagnosis. The study also examined breed distribution, dividing breeds into categories based on predisposition and size. Age distribution was assessed, comparing the average age of DCM patients upon diagnosis to other canine cardiac patients. The study also looked at the percentage of DCM patients diagnosed at different age ranges over time.
Additionally, the study incorporated data on the growth of annual grain-free pet food sales in the United States from 2011 to 2019. The sales figures were sourced from various retail channels but excluded online sales and certain retail outlets like farm and feed stores, veterinary clinics, and hardware stores due to tracking limitations. The study specifically focused on grain-free pet food sales, as it investigated their potential association with DCM, unlike grain-inclusive pet foods.
Surprisingly, the research did not reveal a significant increase in the national incidence rate of DCM over this two-decade period, despite a staggering 500% surge in grain-free pet food store sales between 2011 and 2019. Furthermore, there was no substantial correlation observed between the national DCM incidence rate and the sales of grain-free pet food.
The researchers had access to a substantial dataset of over 68,000 canine cardiology cases from referral hospitals specializing in veterinary cardiology. These cases were diagnosed between 2000 and 2019, and the average incidence rate of DCM among these cases during the survey period was 3.9%, with a range of 2.53% to 5.65%. In addition to this clinical data, the study also analyzed sales figures for grain-free pet food, sourced from the Nielsen Company, highlighting the aforementioned 500% growth in sales during the specified period.
Dr. Stephanie Clark, PhD, CVT, PAS, CFS, Dpl. ACAS, a board-certified companion animal nutritionist and co-author of the article from BSM Partners, commented on the findings, stating, "Based on the data we received from veterinary cardiologists across the United States, we did not observe a significant increase in the incidence rate of DCM over time, which included the recent period when grain-free pet food sales grew exponentially. The existing scientific literature indicates that nutritional factors can lead to the development of DCM, but we did not find a correlation in the DCM incidence rate with grain-free pet food sales."
Dr. Stacey Leach DVM, DACVIM, another co-author of the study and Chief of Cardiology and Associate Teaching Professor of Cardiology at the University of Missouri's Veterinary Health Center, emphasized the significance of their research, stating, "This work is unique because we only examined cases of canine DCM diagnosed by veterinary cardiologists and is a significant addition to our understanding of DCM.
To read the full article, click the link here!
Despite its limitations, this dataset represents the most comprehensive information available to date regarding the occurrence of DCM diagnosed by veterinary cardiologists over an extended period. Furthermore, it introduces previously undisclosed insights into the growth of grain-free pet food sales between 2011 and 2019. While the data suggests a consistent overall trend in DCM incidence over time, it does indicate an uptick in DCM cases among mixed breed dogs in the practices involved in this study.
It's important to note that the data was collected from only a subset of cardiology practices and may not be fully representative of the entire country. Notably, the data reveals a substantial five-fold increase in grain-free pet food sales during the same period. To comprehensively assess any potential correlation between specific nutrients in pet foods and the development of DCM in dogs, further research will be essential.
Quest, Bradley W., Stacey B. Leach, Shiva Garimella, August Konie, and Stephanie D. Clark. "Incidence of canine dilated cardiomyopathy diagnosed at referral institutes and grain-free pet food store sales: a retrospective survey." Frontiers in Animal Science 3 (2022): 11.
BSM Research Team. “DCM Incidence in Dogs Remained Flat with No Correlation to 500% Growth of Grain-Free Diet Category Over Nearly a Decade” (2022). https://bsmpartners.net/resources/dcm-incidence-in-dogs-remained-flat-with-no-correlation-to-500-growth-of-grain-free-diet-category-over-nearly-a-decade/
