Determinants of lipoprotein(a) test utilization in Ontario following public reimbursement: a population-based analysis

Background

European and Canadian guidelines recommend at least one lifetime measurement of lipoprotein (a) [Lp(a)] to refine cardiovascular risk assessment. Universal public funding for Lp(a) testing was implemented in November 2021 in Ontario, Canada.

Purpose

To investigate sociodemographic and clinical factors associated with receipt of Lp(a) testing in Ontario, and their changes relative to introduction of public funding.

Methods

We conducted a population-based study using linked administrative health databases in Ontario from 2007 to 2025. Individuals who underwent Lp(a) testing were matched 1:3 on age and index date of testing (±30 days) to those who received only a standard lipid profile, to account for health service utilization. Lp(a) tests were categorized as pre-funding (before November 2021), early post-funding (November 2021 to October 2022), and late post-funding (November 2022 to March 2025). Multivariable logistic regression was used to identify factors independently associated with Lp(a) testing within each period.

Results

A total of 420,511 individuals underwent Lp(a) testing and were matched to 1,261,533 controls. The mean (±SD) age in the overall cohort was 56.3 (± 14.4) years and 51.8% were females. Lp(a) was predominantly reported in nmol/L (96.2%), with a mean of 70.6 (±91.3) nmol/L and a median of 28 (IQR 11-94) nmol/L. A total of 12,174 (2.9%) Lp(a) tests were done before public funding, 50,220 (11.9%) during the early post-funding period, and 358,117 (85.2%) during the late post-funding period.

Compared with the receipt of a standard lipid profile, Lp(a) testing was less likely among females versus males (odds ratio [OR] 0.88; 95% CI 0.88-0.89), immigrants versus long-term residents (OR 0.81; 95% CI 0.81-0.82), and individuals with the lowest material resources versus highest (OR 0.63; 95% CI 0.62-0.64). The OR for receiving Lp(a) tests in these groups increased over time (Figure). Disparities persisted among individuals with diabetes or dialysis-dependent chronic kidney disease and were amplified among frail individuals and those living in rural areas. The OR of receiving Lp(a) testing among patients with ischemic heart disease decreased over time, from 1.86 (95% CI 1.72 - 2.01) pre-funding to 1.37 (95% CI 1.35 - 1.39) late post-funding.

Conclusion

Public funding for Lp(a) testing was associated with attenuation of some disparities in testing although they were not eliminated. It was also associated with greater inclusion of people without established cardiovascular disease.Figure_combined