Characterization of lipoprotein (a) testing in Alberta, Canada: a retrospective cohort study

BACKGROUND AND AIMS: Patients with elevated lipoprotein (a) (Lp(a)) levels face increased risk of cardiovascular events. However, Lp(a) testing has only recently been recommended as routine clinical practice. This study examines real-world baseline characteristics, healthcare resource utilization (HCRU), costs, lipid-lowering therapy (LLT) treatment intensification, and major adverse cardiovascular events (MACE) among individuals with Lp(a) testing. METHODS: This retrospective, observational study analyzed population-level administrative health data from Alberta, Canada. Individuals with Lp(a) testing were indexed on the first Lp(a) test date occurring between January 1, 2015 and March 31, 2023 and stratified by prior atherosclerotic cardiovascular disease (ASCVD) status and Lp(a) levels (≤50, >50, >70, and >90 mg/dL). RESULTS: The study included 29,229 individuals with Lp(a) testing, of which 7787 (26.6 %) had prior ASCVD. HCRU/costs in the year prior to index, and LLT intensification and MACE rates during follow-up were generally highest in individuals who had both prior ASCVD and an elevated Lp(a) level. Median total costs (per 100 patient-years) and MACE rates (95 % confidence interval, per 1000 person-years) were numerically higher in patients with prior ASCVD who also had elevated Lp(a) levels [>50 mg/dL: $9,315, 32.7 (26.6-38.9); >70 mg/dL: $11,828, 34.2 (26.7-41.6); >90 mg/dL $14,835; 33.1 (24.1-42.1)] compared to those with lower Lp(a) levels ($5,976, 27.0 (23.8-30.4)). CONCLUSIONS: Individuals with elevated Lp(a) levels and prior ASCVD had numerically greater HCRU/costs and subsequent MACE rates. Understanding of the characteristics and outcomes in the context of ASCVD status is important to develop risk assessment and management strategies for those with elevated Lp(a).