For adults with idiopathic dilated cardiomyopathy (IDCM) there is a substantial estimated likelihood of a first-degree family member also having IDCM. A substantial prevalence for a modeled cumulative risk was also detected among first-degree relatives. These study findings were published in the Journal of the American Medical Association.

Researchers sought to estimate the prevalence of familial IDCM in IDCM probands—patients with IDCM, defined as left ventricular systolic dysfunction and left ventricular enlargement—and then determine the age-specific cumulative risk for IDCM in first-degree relatives across age and ethnicity groups. This family-based, cross-sectional study (ClinicalTrials.gov Identifier: NCT03037632) was conducted by a consortium of heart failure (HF) programs at 25 US clinical sites and included 1220 probands, with a median age of 52.8 years (IQR, 42.4-61.8; 43.8% women; 43.1% Black and 8.3% Hispanic patients). Researchers subsequently screened a median of 28% (IQR, 0% to 60%) of living first-degree relatives per proband family, which was 1693 first-degree relatives in total.

Among probands, researchers found an 11.6% crude prevalence of familial IDCM and noted that the model-based estimate among probands, should all living first-degree relatives be screened, was 29.7% (95% CI, 23.5% to 36.0%). Black probands had a higher estimated prevalence of familial IDCM than White probands (difference, 11.3% [95% CI, 1.9% to 20.8%]) and no significant difference between Hispanic and non-Hispanic probands (difference, -1.4% [95% CI, -15.9% to 13.1%]) was found.


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Researchers also noted that, in first-degree relatives at a typical US advanced HF program based on age-specific disease status at enrollment, estimated cumulative risks for IDCM reached 19% (95% CI, 13% to 24%) by 80 years of age. Frist-degree relatives of non-Hispanic, Black probands faced greater risk for IDCM than non-Hispanic, White probands (hazard ratio, 1.89 [95% CI, 1.26 to 2.83]).

The study authors noted limitations in the study, including the lower relative percentage of non-Hispanic, Black first-degree relatives in the probands enrolled and that the non-Hispanic, Black probands tended to be in worse health than non-Hispanic, White probands, with family members who were slightly more likely to have had a prior IDCM diagnosis. The study was also conducted solely among living probands and first-degree relatives. Cumulative risks were not modeled using prospective cohort data. Since the study was conducted only in HF and transplantation programs, the results may lack generalizability. Lastly, analysis relied on statistical modeling and various assumptions and other choices were possible for marginal standardization.

“[T]here was substantial estimated prevalence of familial [I]DCM among [I]DCM probands and modeled cumulative risk [for] [I]DCM among their first-degree relatives,” the researchers wrote. They also noted, “…the finding that first-degree relatives of non-Hispanic Black probands had increased risk [for] [I]DCM underscores the importance of making clinical screening of at-risk family members available to this population.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Huggins GS, Kinnamon DD, Haas GJ, et al. Prevalence and cumulative risk of familial idiopathic dilated cardiomyopathy. JAMA. Published online February 1, 2022. doi:10.1001/jama.2021.24674