Diagnosis of familial hypercholesterolemia: a work in progress

ABSTRACT

Purpose: An ICD-10 code for Familial Hyperchole sterolemia (FH), E78.01, became effective October 2016 following a proposal in 2013 to the ICD-10 Coordination and Maintenance Committee by the Family Heart Foundation. The code differentiated FH from other forms of elevated cholesterol, signaling the need for differential diagnosis of a condition in which management in the first two decades of life can substantially reduce the burden of aggressive atherosclerosis. This study aims to characterize the % of FH patients diagnosed with E78.01 in an expansive, real-world US dataset. Method(s) The Family Heart DatabaseTM includes diagnostic/ procedural/prescription data from claims and/or laboratory data for >300 million individuals from the US who were screened or treated for any form of cardiovascular risk. This analysis dataset includes 197 million people, including 22 million children, with diagnostic data from October 2016 through June 2020. The number of total (diagnosed + undiagnosed) FH patients within the dataset was estimated assuming an occurrence of 1250 individuals. Patients with FH (E78.01) were counted if the diagnostic code was applied for a single in-patient claim or at least twice, >7 days apart, for an out-patient claim. Result(s) The number of patients diagnosed with FH using E78.01 has increased substantially since 2016. During 2017 and 2018, use of the code was brisk and likely included previously and newly diagnosed individuals. Diagnosis was reduced dramatically with the onset of the COVID-19 pandemic corresponding with the marked reduction of in-person clinic visits and near halting of preventive care. By June 2020, 246,689 patients were diagnosed with FH representing 31.3% of the estimated total (diagnosed + undiagnosed) FH population of 787,886 within the dataset. Compared with all individuals in the analysis dataset, those diagnosed with FH were substantially more likely to have atherosclerotic cardiovascular disease (40% versus 8%). Conclusion(s) Prior to 2016, an estimated <1% of patients with FH in the US were diagnosed, but without an ICD code it was impossible to track. The number of patients diagnosed with FH (E78.01) has increased substantially since 2016. Within this large, real-world dataset of Americans, 31.3% of the estimated FH population had been diagnosed as of June 2020. However, despite clear screening guidelines, effective therapies, and classification of FH as a public health threat by the World Health Organization, most of the FH population remains undiagnosed, leaving these genetically vulnerable individuals at high risk for premature cardiovascular disease.