Prevalence of Lipoprotein(a) Testing in Patients With Atherosclerotic Cardiovascular Disease Within a Large Australian Cardiology Network

BACKGROUND: Increased lipoprotein(a) (Lp[a]) is a genetically determined causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Historically, Lp(a) testing has been uncommon in Australia. This study aims to assess the prevalence and trends in Lp(a) testing in Australia, and the associated patient characteristics. METHOD: This retrospective cross-sectional study examined over 1.1 million de-identified electronic medical records from patients seen in the Advara HeartCare network from 2011 to 2022. Adult patients from 2011 to 2021 comprised the historical group, while those from 2022 formed the baseline group. A natural language processing algorithm identified patients with ASCVD and Lp(a) testing, and extracted demographics, characteristics, and cardiovascular comorbidities from clinical letters. Patients with ASCVD in the baseline group were followed up for 18 months to assess trends in Lp(a) testing. RESULTS: Testing Lp(a) was infrequent among patients with ASCVD but increased gradually over time. In the historical cohort, of 164,121 patients identified with ASCVD, 1,501 (0.9%) underwent Lp(a) testing. Of these, 44.8% had Lp(a) levels <30 mg/dL, and 25.0% >90 mg/dL. In the baseline cohort, 1,460 (2.6%) of 55,427 patients with ASCVD underwent Lp(a) testing. Of 730 with recorded Lp(a) values, 30.2% had Lp(a) levels ≥70 mg/dL, and 86.8% were on lipid-lowering therapy. Dyslipidaemia was the most common comorbidity (72.8%), followed by Stage 1 or 2 chronic kidney disease (40.1%). During 18-month follow-up from the baseline period, 329 additional patients underwent Lp(a) testing in 2023. CONCLUSIONS: The study revealed that Lp(a) testing is underutilised among patients with ASCVD in Australia despite recent guidelines recommending it. This emphasises the need to expand Lp(a) testing to improve health outcomes for high-risk patients.