Abstract 17960: Lipoprotein(a) Testing Frequency and Predictors in a Multiethnic Health System

Introduction: Lipoprotein(a) [Lp(a)] is a causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Contemporary practice guidelines recommend incorporating Lp(a) testing into routine clinical practice. We examined the prevalence of Lp(a) testing and characteristics that predicted which individuals underwent testing.

Methods: This was a retrospective cohort study. Eligible individuals were patients of a large Northern Californian health system with 2 or more primary care visits between the years 2010 to 2021. Incident density matching was used to select controls matched with a case if a visit date was within ±6 months of the index date of initial Lp(a) test. Prevalence of Lp(a) testing was determined by year. Conditional logistic regression was used to assess the relationship between Lp(a) testing and sociodemographic, clinical, and healthcare utilization variables.

Results: Of the 1,484,410 individuals in the cohort, 12,506 (0.84%) had their Lp(a) level checked. The median Lp(a) level was 35 mg/dL and 5,598 (37.78%) of those who underwent testing had a Lp(a) level > 50mg/dL. Among those with Lp(a) testing, there was a higher proportion of Asian individuals and a lower proportion of non-Hispanic Black and Hispanic individuals. In adjusted-analyses, those with a history of ASCVD had over twice the odds of undergoing testing (OR = 2.11 (95% CI = 1.98, 2.26)). South Asian individuals were three times more likely to have undergone Lp(a) testing as compared to non-Hispanic White individuals (OR = 3.25, (95% CI = 3.06, 3.46)), while those identified as non-Hispanic Black and Hispanic were significantly less likely to have undergone Lp(a) testing (OR = 0.7, (95% CI = 0.62,0.8) and 0.62 (95% CI = 0.57, 0.67), respectively).

Conclusions: This study examined the real-world clinical testing patterns of Lp(a) over a decade within a large, diverse health system. Expanding access to Lp(a) testing may help reduce disparities within ASCVD risk assessment and treatment.