Lipoprotein(a) Levels in Disaggregated Racial and Ethnic Subgroups Across Atherosclerotic Cardiovascular Disease Risk Levels.

Background: Lipoprotein(a) [Lp(a)] is a causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Objectives: The authors assessed differences in Lp(a) testing and levels by disaggregated race, ethnicity, and ASCVD risk. Methods: This was a retrospective cohort study of patients from a large California health care system from 2010 to 2021. Eligible individuals were ≥18 years old, with ≥2 primary care visits, and complete race and ethnicity data who underwent Lp(a) testing. Race and ethnicity were self-reported and categorized as follows: non-Hispanic (NH) White, NH-Black, Hispanic (Mexican, Puerto Rican, other), NH-Asian (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese, other). Logistic regression models tested associations between elevated Lp(a) (≥50 mg/dL) and race, ethnicity, and ASCVD risk. Results: 13,689 (0.9%) individuals underwent Lp(a) testing with a mean age of 54.6 ± 13.8 years, 49% female, 28.8% NH Asian. Over one-third of those tested had Lp(a) levels ≥50 mg/dL, ranging from 30.7% of Mexican patients to 62.6% of NH-Black patients. The ASCVD risk of those tested varied by race: 73.6% of Asian Indian individuals had <5% 10-year risk, whereas 27.2% of NH-Black had established ASCVD. Lp(a) prevalence ≥50 mg/dL increased across the ASCVD risk spectrum. After adjustment, Hispanic (OR: 0.76 [95% CI: 0.66-0.88]) and Asian (OR: 0.88 [95% CI: 0.81-0.96]) had lower odds of Lp(a) ≥50 mg/dL, whereas Black individuals had higher odds (OR: 2.46 [95% CI: 1.97-3.07]). Conclusions: Lp(a) testing is performed infrequently. Of those tested, Lp(a) levels were frequently elevated and differed significantly across disaggregated race and ethnicity groups. The prevalence of elevated Lp(a) increased with increasing ASCVD risk, with significant variation by race and ethnicity.