<p><strong>Background</strong> Universal lipid screening in children provides an opportunity to mitigate the lifetime risk of atherosclerosis, particularly in children with chronic conditions that are predisposed to early atherosclerosis. In response, national guidelines recommend additional early screening in a subset of cardiac conditions. The penetration of such guidelines has not been evaluated. <strong>Methods and Results</strong> We performed a retrospective study of a geographically representative sample of US children using the MarketScan Commercial and Medicaid claims databases. The study population was children with cardiac disease between ages 2 and 18 years and ≥3&nbsp;years of continuous coverage from January 1, 2013, to June 30, 2018, divided into 4 major strata of heart disease. We assessed the likelihood of screening between these classifications and compared with healthy children and calculated multivariate models to identify patient factors associated with screening likelihood. Of the eligible 8.4 million children, 155&nbsp;000 children had heart disease, of which 1.8% (31&nbsp;216) had high-risk conditions. Only 17.5% of healthy children underwent lipid screening. High-risk children were more likely to be screened (odds ratio [OR], 2.1; 95% CI, 2.09-2.19; &lt;0.001) than standard-risk children, but that likelihood varied depending on strata of cardiac disease (22%-77%). Timing of screening also varied, with most occurring between ages 9 and 11 years. Among cardiac conditions, heart transplantation (OR, 16.8; 95% CI, 14.4-19.7) and cardiomyopathy (OR, 2.9; 95% CI, 2.8-3.1) were associated with the highest likelihood of screening. <strong>Conclusions</strong> Children with cardiac disease are more likely to undergo recommended lipid screening than healthy children, but at lower rates and later ages than recommended, highlighting the importance of quality improvement and advocacy for this vulnerable population.</p>

<p>Because atherosclerosis begins in childhood, universal lipid screening is recommended with special attention to conditions predisposing to early atherosclerosis. Data about real-world penetration of these guidelines is not available.</p>

<p><strong>METHODS: </strong>Retrospective cohort study using MarketScan® commercial and Medicaid insurance claims databases, a geographically representative sample of U.S. children. Subjects who passed through the 9- to 11-year window and had continuous insurance coverage between 1/1/2013 and 12/31/2016 were studied. Multivariable models were calculated, evaluating the association between other patient factors and the likelihood of screening. The primary hypothesis was that screening rates would be low, but that high-risk conditions would be associated with a higher likelihood of screening.</p>

<p><strong>RESULTS: </strong>In total, 572,522 children (51% male, 33% black, 11% Hispanic, 51% Medicaid) were studied. The prevalence of high-risk conditions was 2.2%. In unadjusted and adjusted analyses, these subjects were more likely to be screened than standard-risk subjects (47% vs. 20%, OR: 3.7, 95% CI 3.5-3.8, P &lt; .001). Within this group, the diagnosis-specific likelihood of screening varied (26-69%). Endocrinopathies (OR 5.4, 95% CI 5.2-5.7), solid organ transplants (OR 5.0, 95% CI 3.8-6.6), and metabolic disease (OR 3.9, 95% CI 3.1-5.0, all P &lt; .001) were associated with the highest likelihood of undergoing screening.</p>

<p><strong>CONCLUSIONS: </strong>Despite national recommendations, lipid screening was performed in a minority of children. Though subjects with high-risk conditions had a higher likelihood of screening, rates remained low. This study highlights the need for research and advocacy regarding obstacles to lipid screening of children in the United States.</p>