Systematic screening of families with possible familial dilated cardiomyopathy (DCM) identifies a high baseline prevalence of the disorder among relatives, thus demonstrating strong support for family screening, according to the results of a retrospective, longitudinal cohort study that was published in the journal JACC: Heart Failure.
Recognizing that a growing body of evidence supports the benefits of cascade screening to diagnose presymptomatic familial DCM and thus allow for early intervention, researchers sought to explore the prevalence and incidence of, and to identify predictors of development of familial DCM, among relatives who participated in family screening.
Patients with DCM and their relatives were followed at The Capital Region’s Units for Inherited Cardiac Diseases, at Copenhagen University Hospital, located in Denmark, a regional assembly of tertiary referral sites in the Greater Copenhagen area. Individuals were referred for screening by general practitioners, private cardiologists, and local cardiology or heart failure clinics in instances of unexplained left ventricular dilation and systolic dysfunction. A family history of DCM was not needed for referral.
A total of 211 families, 563 of whom were relatives and 50% of whom were women, were included in the study. Overall, 22% of the relatives were diagnosed with familial DCM. Based on genetic sequencing, the etiology of DCM was identified in 37% of the families who were screened, with 18% of the relatives classified as unaffected carriers (n=43) or noncarriers (n=58). When combined, the clinical and baseline yield of screening was 30%.
During follow-up (2313 person-years; median 5.0 years), 45 individuals developed familial DCM (incidence rate per person-year, 2.0%; 95% CI, 1.4-2.8%), thus increasing the overall yield to 34%. The incidence rate of familial DCM was high in relatives who had baseline abnormalities on electrocardiography or echocardiography, compared with relatives who had normal findings (4.7% vs 0.4% per person-year, respectively; hazard ratio, 12.9; P <.001). Overall, baseline screening identified 58% of relatives as being at low risk for familial DCM.
Several limitations include that the cohort is from a regional assembly of tertiary referral sites, which might introduce a selection/referral bias of families in which the index patient presents at an earlier age, with a more severe phenotype, and in which a history of disease is evident. Additionally, a participation bias might lead to an inflation of the clinical yield.
“…these findings provide important information for developing data-driven guidelines for future follow-up regimens for DCM relatives,” the study authors wrote.
Vissing CR, Espersen K, Mills HL, et al. Family screening in dilated cardiomyopathy: prevalence, incidence, and potential for limiting follow-up. JACC Heart Fail. Published online September 7, 2022. doi:10.1016/j.jchf.2022.07.009