Prevalence and description of dogs with dilated cardiomyopathy eating hydrolyzed protein diets

To compare the signalment of dogs with dilated cardiomyopathy (DCM) eating hydrolyzed and nonhydrolyzed protein diets, and to characterize clinical data and echocardiographic indices of dogs with DCM eating hydrolyzed protein diets.

Medical records of dogs diagnosed with DCM between May 2018 and October 2023 were retrospectively reviewed. Clinical data were compared between dogs eating hydrolyzed and nonhydrolyzed protein diets. For the latter group, presence of arrhythmias or congestive heart failure, whether diet was changed, and echocardiographic measurements were recorded.

From 2,222 dogs diagnosed with DCM, 2,105 dogs met the study's inclusion criteria. Twenty-eight of 2,105 dogs (1.3%) were eating hydrolyzed protein diets. The most common breeds were pit bull-type breed (n = 6), English Bulldog (4), and Doberman Pinscher (4). Seventeen of 28 dogs (60.7%) had arrhythmias, and 17 of 28 dogs (60.7%) had congestive heart failure. There were no significant differences in age, sex, or body weight between the 2 diet groups. Five of 28 dogs eating hydrolyzed protein diets had follow-up echocardiograms and changed diet. In these 5 dogs, there was a significant reduction in left atrial-to-aortic ratio (from median 1.24 to 1.09; effect size, 0.64) and normalized left ventricular internal dimension at end systole (from median 1.41 to 1.25; effect size, 0.64) at the follow-up examination.

In a large population of dogs with DCM, 1.3% were eating hydrolyzed protein diets prior to diagnosis; only a small number had follow-up echocardiograms.

The role of hydrolyzed protein diets in DCM is unclear but warrants further investigation.