Prevalence and Clinical Burden of Idiopathic Dilated Cardiomyopathy in the United States

Dilated cardiomyopathy (DCM) contributes significantly to heart failure prevalence, yet supporting epidemiologic data is sparse. This study sought to estimate the period prevalence of DCM and the proportion of idiopathic DCM in the US using a large, diverse electronic health records (EHR) database. This retrospective, observational study included 56,812,806 deidentified patients in Optum® EHR between 2017-2019. Suspected DCM cases were identified using ICD-10 coding. Deidentified clinical notes from 1,000 randomly selected cases were manually reviewed to determine the diagnosis of DCM and estimate the proportion of idiopathic DCM. The period prevalence and clinical burden of DCM and idiopathic DCM were estimated. Manual clinical review demonstrated that our definition had a positive predictive value of 92.5% for DCM with 46.3% estimated as the idiopathic DCM proportion. The estimated period prevalence of DCM between 2017-2019 was 118.33 per 100,000. Prevalence increased for adults ≥ 65 years of age, males, and African Americans. Extrapolation to the 2019 US population led to an overall estimated burden of roughly 388,350 patients. Adjusting for the proportion of cases with idiopathic DCM yielded an idiopathic DCM prevalence of 59.23 per 100,000 and a burden of 194,385 patients. Evidence of clinical genetic testing in this population was scarce, with less than 0.43% of DCM cases reporting a testing code. This study establishes a conservative period prevalence for DCM and idiopathic DCM, and demonstrates very low molecular genetic testing for DCM. These findings suggest that the clinical burden of genetic DCM may be underestimated.