Low Lp(a) Testing in ASCVD: Higher Levels in Black and Female Patients

Elevated lipoprotein(a) [Lp(a)] is a common inherited dyslipidemia linked to increased atherosclerotic cardiovascular disease (ASCVD) risk.1 However, data from diverse populations remain limited. This subanalysis of the Lp(a)HERITAGE study revealed that only 14% of US patients with ASCVD had Lp(a) measured pre-enrollment, with elevated levels more prevalent among Black and female participants, highlighting the need for targeted Lp(a) testing.

Study identifies underutilization of testing, with disparities by race and sex. | Image credit: Zhanna - stock.adobe.com

The subanalysis study is published in the Journal of Clinical Lipidology.

“The results of this US subanalysis of the global Lp(a)HERITAGE study highlight several key insights,” wrote the researchers of the study. “Despite being an established, independent, and predominantly genetically determined condition and causal risk driver for ASCVD, most patients with ASCVD in the US are currently managed without knowledge of their Lp(a) levels.”

The Lp(a)HERITAGE study (NCT03887520) was a multicenter, cross-sectional, epidemiological study designed to estimate the prevalence of elevated Lp(a) levels in individuals with clinical ASCVD as defined by their medical history.2 Eligible participants were adults aged 18 to 80 years with a history of myocardial infarction (MI), ischemic stroke, or symptomatic peripheral arterial disease (PAD) within 3 to 10 years before study enrollment.

For this subanalysis, US participants with Lp(a) measured in nmol/L were included. Demographic data, including age, sex, race, and ethnicity, were collected, and prior Lp(a) and low-density lipoprotein cholesterol (LDL-C) values were accepted if obtained within 5 years and 1 year of enrollment, respectively.1 Blood samples were tested for Lp(a) and LDL-C. The primary objective was to assess the prevalence of normal and elevated Lp(a) levels in individuals with ASCVD, while secondary objectives examined the distribution of Lp(a) and LDL-C levels. Descriptive statistics were used to summarize data, and no statistical comparisons were made in this analysis.

A total of 8295 US participants from 192 sites were enrolled in the study between April 2019 and July 2021. Of these, 7679 participants were included in this subanalysis, comprising those with an Lp(a) measurement in nmol/L prior to study enrollment (n = 552) and those who had Lp(a) measured during the study period (n = 7127).

The prevalence of Lp(a) measurements prior to study enrollment was 14% in the overall population, with 14.3% of White, 11.8% of Black, and 9.1% of Hispanic participants having a prior Lp(a) measurement. Among male and female participants, 13.7% and 14.9%, respectively, had an available prior Lp(a) measurement.

Additionally, 80.5% of participants identified as White, 16.9% as Black, and 8.0% as Hispanic. Two-thirds of participants were male (66.4%), and the mean (SD) age was 63.8 (9.7) years. Notably, the proportion of participants aged 65 years and older and 75 years and older was lower in Black (44.2% and 8.9%, respectively) and Hispanic (46.0% and 11.6%, respectively) subgroups compared with the overall population (52.3% and 13.4%, respectively).

However, the researchers noted several limitations. First, the study and subanalysis were purely descriptive in design. Second, as local laboratory values were used, the lack of standardization between assays for measuring Lp(a) could have influenced the results. Third, the inclusion of expert centers may have biased participant recruitment, resulting in a higher historical rate of Lp(a) testing.

Despite these limitations, the researchers believe the study highlights the underutilization of Lp(a) testing in US individuals with ASCVD, despite the strong association between elevated Lp(a) levels and increased cardiovascular risk, especially among Black and female participants.

“Despite the lack of currently available pharmacological Lp(a)-lowering therapies, elevated Lp(a) is actionable now, and more widespread Lp(a) testing may help improve CVD [cardiovascular disease] risk stratification and facilitate the initiation of risk-mitigation strategies as part of a heart-healthy lifestyle,” wrote the researchers.

References

1. Shapiro MD, Haddad TM, Weintraub HS, et al. Lipoprotein(a) levels in a population with clinical atherosclerotic cardiovascular disease in the United States: A subanalysis from the LP(a)Heritage Study. Journal of Clinical Lipidology. Published online December 3, 2024. doi:10.1016/j.jacl.2024.11.007

2. Lipoprotein(a) in patients with cardiovascular disease (CVD). NIH. January 28, 2022. Accessed December 17, 2024. https://clinicaltrials.gov/study/NCT03887520.