Coronary Artery Disease Risk of Familial Hypercholesterolemia Genetic Variants Independent of Clinically Observed Longitudinal Cholesterol Exposure
Shoa L. Clarke, Catherine Tcheandjieu, Austin T. Hilliard, Kyung Min Lee, Julie Lynch, Kyong-Mi Chang, Donald Miller, Joshua W. Knowles, Christopher O’Donnell, Philip S. Tsao, Daniel J. Rader, Peter W. Wilson, Yan V. Sun, J. Michael Gaziano, Themistocles L. Assimes, VA Million Veteran Program
Abstract
Background: Familial hypercholesterolemia (FH) genetic variants confer risk for coronary artery disease independent of LDL-C (low-density lipoprotein cholesterol) when considering a single measurement. In real clinical settings, longitudinal LDL-C data are often available through the electronic health record. It is unknown whether genetic testing for FH variants provides additional risk-stratifying information once longitudinal LDL-C is considered. Methods: We used the extensive electronic health record data available through the Million Veteran Program to conduct a nested case-control study. The primary outcome was coronary artery disease, derived from electronic health record codes for acute myocardial infarction and coronary revascularization. Incidence density sampling was used to match case/control exposure windows, defined by the date of the first LDL-C measurement to the date of the first coronary artery disease code of the index case. Adjustments for the first, maximum, or mean LDL-C were analyzed. FH variants in LDLR , APOB , and PCSK9 (Proprotein convertase subtilisin/kexin type 9) were assessed by custom genotype array. Results: In a cohort of 23 091 predominantly prevalent cases at enrollment and 230 910 matched controls, FH variant carriers had an increased risk for coronary artery disease (odds ratio [OR], 1.53 [95% CI, 1.24–1.89]). Adjusting for mean LDL-C led to the greatest attenuation of the risk estimate, but significant risk remained (odds ratio, 1.33 [95% CI, 1.08–1.64]). The degree of attenuation was not affected by the number and the spread of LDL-C measures available. Conclusions: The risk associated with carrying an FH variant cannot be fully captured by the LDL-C data available in the electronic health record, even when considering multiple LDL-C measurements spanning more than a decade.