Underutilization Of Guideline-directed Genetic Testing In Cardiomyopathies: A Missed Opportunity

Introduction Guidelines from U.S. cardiology societies recommend genetic testing in individuals with suspected diagnoses of hypertrophic cardiomyopathy (HCM) or dilated cardiomyopathy (DCM). Major U.S. payors have therefore adopted favorable reimbursement policies. Establishing a genetic etiology is important for prognostication and management of affected individuals, cascade testing of at-risk family members, and identification of pre-symptomatic carriers. Hypothesis Adherence to genetic testing practice guidelines from U.S. cardiology societies is limited. Methods HCM and DCM cohorts were identified based on new HCM/DCM diagnoses (via ICD-10-CM codes) between 10/1/2016 and 3/1/2020 in the Veradigm EHR Database (170M unique patient records, 35K outpatient US practices). Genetic testing was captured with ICD-10 codes or structured text elements indicating genetic testing (excluding testing that could be unambiguously associated with non-cardiology indications, e.g., cancer), as well as surrogate markers of genetic testing (e.g., referrals to genetic clinics). Cohorts were characterized across demographics, clinical measurements, provider visits, and baseline comorbidities. Results Among individuals with a diagnosis of new-onset HCM or DCM, 22,254 and 69,331, respectively, met all inclusion criteria. The HCM cohort had a median age of 67 (IQR: 57-76) years and was 53% female; the DCM cohort had a median age of 70 (IQR: 60-78) years and was 37% female. Only a small proportion of newly diagnosed HCM (0.32%) and DCM (0.38%) patients received guideline-recommended genetic testing. Even among patients with family history of HCM or DCM, who are at increased risk for an inherited cardiomyopathy, a small fraction received guideline-directed genetic testing (1.9% and 3.3% for HCM and DCM, respectively). Most patients who received genetic testing did so after a clinical diagnosis was made (70% for HCM, 90% for DCM), not before. Individuals for whom the initial diagnosis was entered in the EHR by a cardiologist (as compared to a non-cardiology healthcare provider) were 3.5 times (HCM) and 3.9 times (DCM) as likely to receive genetic testing. Conclusions Practice guidelines recognize that the rationale to identify cardiomyopathy-based genetic risk is medically actionable to direct cascade testing and allow for early intervention. However, we found that genetic testing guidelines are rarely followed in practice. Real-world data analysis provided insights into the actual delivery of genomic health care in a clinical setting. Lack of adherence to guideline-directed testing was identified as a critical area.