Racial Differences in the use of Genetic Testing among Patients with Hypertrophic Cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM), the prototypical cardiovascular genetic disease, is caused by dominantly inherited mutations in genes encoding sarcomeric proteins. Genetic testing is recommended for individuals with HCM, the results of which promote prevention of morbidity and mortality through detection of disease in at-risk relatives. However, utilization of genetic testing in clinical medicine has not been widely adopted. Prior studies of inherited cancer syndromes have noted racial inequities in access to genetic testing. The aim of this study was to investigate for structural inequities in referral to a cardiovascular genetics clinic for genetic testing and counseling among Black, Latinx, and female patients with HCM. Methods We performed a case-control study (January 2012-December 2017) of 280 patients with HCM within a large academic health system. HCM patients were identified by ICD-9 diagnostic codes, and then verified by manual chart review. Of these 280 patients, 20% were referred to cardiovascular genetics clinic for genetic testing (cases) and 80% were not (controls). Demographic factors including race and gender were extracted for both cases and controls. Fischer exact, χ2tests, and t tests were used to assess the statistical significance of difference in the characteristics of cases and controls as indicated. Results HCM patients who were referred to cardiovascular genetics clinic for genetic testing (cases) were less likely to be black (5.4% of cases vs. 8.0% of controls) and less likely to be female (46.4% of cases vs 56.7% controls), but this did not achieve statistical significance (p=0.82 for race; p=0.17 for gender). English language was not associated with referral (p=0.30). Older patients, however, were significantly less likely to be referred for genetic testing (odds ratio 0.94 [95% CI 0.92, 0.96][p Conclusions Overall referral rates to a cardiovascular genetics clinic for genetic testing were low among patients with HCM. Additional ascertainment is important to understand if the demonstrated trends are significant on a larger scale.