Underutilization of Lipoprotein(a) Testing and Its Association with Coronary Interventions: PITT-LIPID Real-world Registry Insights

Background: Lipoprotein(a) [Lp(a)], is leading risk factor for premature atherosclerotic cardiovascular disease. Multi-societal guidelines recommend to test Lp(a) amongst adults at least once, however, real-world testing data in primary prevention populations remains scarce. Objectives: To investigate the utilization of Lp(a) testing in a primary prevention cohort and associated outcomes. Methods: We conducted a retrospective cohort study using data from the PITT-LIPID registry, an electronic health record (EHR) based database of primary prevention patients (ages 20-79 years) across a tristate healthcare network. Lp(a) testing status was assessed, and those with Lp(a) measurements were stratified by Lp(a) levels [&le;]125 versus >125 nmol/L. Multivariable Cox proportional hazards models were used to assess associations between Lp(a) levels and coronary artery interventions [percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG)], and mortality. Results: Among 687,780 patients without known coronary artery disease, only 6,340 (0.9%) patients underwent Lp(a) testing. Compared with untested patients, those tested for Lp(a) had higher low density lipoprotein cholesterol, greater percentages of statin and aspirin use, and lower prevalence of diabetes and smoking. Patients with Lp(a) testing had higher rates of PCI (4.5% vs 1.4%; p-value <0.001) and CABG (1.4% vs 0.4%; p-value <0.001) but lower all-cause mortality (2.0% vs 5.0%; p-value < 0.001) incidence. Lp(a) >125 nmol/L was independently associated with risk of PCI (HR 1.67, 95% CI [1.16-2.41]), p=0.006. Conclusion: Lp(a) testing was underutilized and associated with higher burden of PCI events in a primary prevention population across a contemporary healthcare network with diverse practice types.