Abstract WP114: Increasing Rates of Lipoprotein(a) Testing in Young Ischemic Stroke Patients from 2015-2024: An Analysis of 300 Million Individuals

Background: Lipoprotein(a) [Lp(a)] is a genetically determined biomarker associated with increased risk of myocardial infarction and stroke. Approximately 20-25% of patients aged ≤60 who have had an ischemic cerebrovascular accident (CVA) have an elevated Lp(a) >50 mg/dL (>125 nmol/L). However, Lp(a) testing remains underutilized in this population, and limited data on national testing trends are available. Methods: This study includes data from Epic Cosmos, a nationwide, de-identified electronic health record dataset comprising over 300 million patients, between January 1, 2015, to December 31, 2024. We evaluated the number of young ischemic stroke patients, defined as age ≤60 with history of an ischemic CVA, who had undergone Lp(a) testing, the testing rate per annual young ischemic stroke patients, geographical variation, and percentages of patients tested stratified by age, sex, ethnicity, race, and diagnosis of coronary artery disease (CAD). Results: From 2015 to 2024, out of a total of 188,305 distinct young ischemic stroke patients, 9,226 (4.90%) underwent Lp(a) testing. Additionally, the annual number of tested patients increased significantly from 179 in 2015 to 1,992 in 2024 (χ 2 test, p<0.001), and the annual percentage of patients undergoing Lp(a) testing increased from 4.28% in 2015 to 9.28% in 2024. Most tests were performed in Ohio (10.4%), Texas (7.4%), and Pennsylvania (5.5%). Age-stratified analyses revealed that testing was most frequently conducted among adults between the ages of 50-60 years (4,460; 48.3%). Lp(a) testing rates were similar by sex, with 52.9% (4,883) among males and 47.1% (4,343) among females. Among patients undergoing testing with reported ethnic identity, only 1,127 (12.2%) identified as Hispanic or Latino, while the remaining 8,809 (87.8%) identified as non-Hispanic. Most patients undergoing testing with reported racial data identified as White (6,000; 65.0%), followed by Black or African American (2,269; 24.6%), Other Race (1,262; 13.7%), Asian (535; 5.8%), and “None of the above” (280; 3.03%). Of the young ischemic stroke patients who had a concurrent diagnosis of CAD, 2,181 (5.24%) underwent testing. Conclusion: Lp(a) testing of young ischemic stroke patients has increased significantly over the past decade, but overall testing remains low. These trends highlight the need to increase awareness of Lp(a), and further efforts are needed to promote standardized Lp(a) testing guidelines for this population.