Prevalence and Correlates of Lipoprotein(a) Testing in a Diverse Cohort of U.S. Adults

BACKGROUND: Once-per-lifetime lipoprotein(a) [Lp(a)] testing is recommended by multiple professional societies during cardiovascular disease risk assessment. OBJECTIVE: The purpose of this study was to assess the prevalence and identify correlates of Lp(a) testing in a real-world, diverse sample. METHODS: Participants were ≥18 years of age from the All of Us Research Study who shared electronic medical record information through 2022 (N = 266,612). Completion of Lp(a) testing was defined by the following: presence of Lp(a) values, Systematized Nomenclature of Medicine Clinical Terms or Logical Observation Identifiers Names and Codes electronic health record listings for Lp(a) testing, or an Internal Classification of Diseases-10 code for elevated Lp(a). Multivariable logistic regression assessed the association of demographic, socioeconomic, and clinical variables with Lp(a) testing. RESULTS: The mean age was 52 years, 61% were women, and 53% were non-Hispanic White. A total of 2,172 (0.8%) underwent Lp(a) testing, 86% of whom had clinical cardiovascular disease. Compared to non-Hispanic White individuals, non-Hispanic Black individuals (OR: 0.68, 95% CI: 0.58-0.81) had 32% lower odds of Lp(a) testing. Less than high school education (OR: 0.34, 95% CI: 0.25-0.44), unemployment (OR: 0.76, 95% CI: 0.68-0.85), and disability (OR: 0.77, 95% CI: 0.65-0.91) were associated with a 23% to 66% lower odds of Lp(a) testing. Among clinical factors, non-Lp(a) lipid abnormality (OR: 5.64, 95% CI: 4.72-6.79) and prevalent cardiovascular disease (OR: 3.21, 95% CI: 2.76-3.74) were strongly associated with Lp(a) testing. CONCLUSIONS: The prevalence of Lp(a) testing among US adults is exceedingly low, especially for non-Hispanic Black individuals and those with socioeconomic risk. These results underline the importance of emphasizing health equity in Lp(a) testing expansion.