P274 - SOCIODEMOGRAPHIC AND CLINICAL CHARACTERISTICS ASSOCIATED WITH RECEIPT OF LP(A) TESTING IN ONTARIO: A POPULATION-BASED CROSS-SECTIONAL ANALYSIS

Background: Elevated lipoprotein (a) [Lp(a)] is an established risk marker for cardiovascular disease and is recommended to be tested in all adults by the 2021 Canadian Cardiovascular Society Dyslipidemia guidelines. In Ontario, universal public funding for Lp(a) testing was implemented in 2021, but it remains unknown which groups of patients are more likely to be screened for elevated Lp(a). This study aimed to investigate sociodemographic and clinical factors associated with Lp(a) testing in the province.

METHODS AND RESULTS: We conducted a population-based, cross-sectional study using linked administrative health databases in Ontario from 2007 to 2023. Each individual who underwent Lp(a) testing was matched on age and index date (±30 days) to five individuals who received a standard lipid profile. Multivariable logistic regression was used to identify factors independently associated with odds of Lp(a) testing.
A total of 185,612 individuals received Lp(a) testing, matched to 928,060 controls. The mean (±SD) age in the overall cohort was 57.1 (± 14.1) years and 51.9% were females. The mean LDL-C in the cohort was 2.70 (±1.04), non-HDL-C 3.38 (±1.14) and triglycerides 1.56 (±1.16) mmol/L. Most Lp(a) tests (94.6%) were done after 2021. Lp(a) was predominantly reported in nmol/L (92.2%), with a mean of 70.8 (±94.3) and a median of 27 (IQR 10–94) nmol/L. For tests reported in mg/dL (7.8%), the mean Lp(a) was 33.9 (±38.6) and the median was 17 (IQR 7.0–47.1) mg/dL. Lp(a) testing was more likely in patients with ischemic heart disease (OR: 1.37; 95% CI: 1.34 to 1.39; p< 0.001), aortic stenosis (OR: 1.13; 95% CI: 1.03 to 1.23; p=0.006), and atrial fibrillation (OR: 1.28; 95% CI: 1.25 to 1.31; p< 0.001). Conversely, rural dwelling (OR: 0.55; 95% CI: 0.54 to 0.56), lower-income status (OR: 0.66; 95% CI: 0.65 to 0.67), immigrant status (OR: 0.86; 95%CI: 0.85 to 0.87) and female sex (OR: 0.88; 95% CI: 0.87 to 0.89) were negatively associated with Lp(a) testing (all p< 0.001; Table).

Conclusion: Lp(a) testing has been increasingly utilized in Ontario. Testing is more common in individuals with cardiac disease, but is less frequent among females, immigrants, rural residents, and individuals of lower socioeconomic status. This study highlights important sociodemographic disparities in access to cardiovascular risk stratification despite removal of direct financial barriers to Lp(a) testing.