Trends and disparities in lipoprotein(a) testing from 2016-2025: a large-scale interrupted time series analysis

Background Elevated Lipoprotein(a) [Lp(a)] is an independent risk for atherosclerotic cardiovascular disease (ASCVD), impacting approximately 20-25% of the global population. Testing remains historically underutilized despite increased guidance for once per lifetime testing. In 2022, our institution observed an increase in testing utilization, aligning temporally with the 2022 AHA ‘Scientific Statement on Lp(a)’. With the emergence of Lp(a) lowering therapies, characterization of testing trends in response to evolving clinical guidance, and identification of disparities in utilization has become increasingly important. Purpose Evaluate temporal trends in Lp(a) testing, assess whether 2022 marked a significant inflection point, identify disparities in testing, and characterize its use in primary prevention. Methods Retrospective cohort study of lipid-tested patients between 2016-2025. One unique lipid panel per patient per year was included, and the first instance of Lp(a) testing was used to assess annual rates. Patients with Lp(a) testing prior to our study period were excluded from the analysis. Whole cohort and sex-stratified interrupted time-series analyses assessed changes in testing trends, using 2022 as a prespecified time point. Multivariable logistic regression was then utilized to assess predictors of testing. Results Among 1,009,156 lipid-tested patients, 75,021 (7.4%) underwent Lp(a) testing. Median age at testing was 53.9 (50,66.9), 59% were male, 89% white, and 72% were tested in primary prevention. On multivariable logistic regression, males (OR 1.26, 95% CI 1.24-1.28, p<0.001), patients with prior ASCVD (OR 1.35, 95% CI 1.32-1.38, p<0.001), and prior hyperlipidemia (OR 1.88, 95% CI 1.85-1.91, p<0.001), were more likely to be tested (Table 1). Prior to 2022, the mean annual testing rate was 1.23% (SD 0.31%), with a rise of 0.15 percentage points per year (95% CI 0.14–0.17; p<0.001). In 2022, an immediate level increase of 1.43 percentage points (95% CI 1.33–1.54; p<0.001) and slope increase of 0.50 percentage points per year (95% CI 0.47–0.53; p<0.001) were observed. Males experienced a larger immediate increase compared to females (1.35 vs 0.55 percentage points; p<0.001) (Figure 1). Conclusions Lp(a) testing experienced sustained acceleration after 2022, demonstrating the impact of education and specialty-specific guidance on clinical practice. Despite increased uptake, overall utilization remains low. A clear sex-based disparity was identified, highlighting well known patterns of under-recognition of cardiovascular diseases amongst women. Although testing primarily takes place in the primary prevention setting, those with baseline ASCVD are more likely to be tested, revealing testing is not yet routine in clinical practice. As Lp(a) targeted therapies near clinical availability, institutions must identify pathways to promote increased testing uptake and employ strategies to ensure equitable utilization.