Model of HDL (left) and LDL (right).
In 2011, the National Heart, Lung, and Blood Institute (NHLBI) updated lipid screening guidelines for children and adolescents, recommending selective screening based on family history or personal risk factors starting at age 2. They also called for universal screening once between ages 9 and 11, and again between ages 17 and 21.
As primary care pediatricians (PCPs) try to incorporate those recommendations into their well childcare routines, though, questions are being raised about the guidelines’ practical implications.
The U.S. Preventive Services Task Force (USPSTF) maintains that there is not enough evidence to recommend for or against routine lipid screening in children and teens. Two 2012 commentaries in the Journal of the American Medical Association echoed this concern, highlighting a lack of evidence that lifestyle changes affect long-term cardiovascular risk in children with moderately elevated lipid levels. They also raised concerns about children being put on medications like statins based on little evidence1,2.
As Sarah de Ferranti, MD, MPH, director of the Preventive Cardiology Clinic at Boston Children’s Hospital, notes, “There is no single large-scale, randomized, controlled study evaluating the impact of pediatric lipid screening.” Nor is one likely, given the protracted lead-time between high cholesterol in childhood and cardiovascular events in adulthood.
Whom to screen: A question of data
Screening could potentially identify high-risk patients with familial hypercholesterolemia, who are at significantly increased risk of having a heart attack between the ages of 20 and 40. “However, it’s still unclear whether universal screening is the best method to identify these patients,” de Ferranti cautions.
Family history is not always an effective screening criterion, she adds, because families don’t always know the necessary details. This unreliability is one reason why universal screening emerged as an alternative option.
“The quality of the data required to answer important questions about the utility of screening this population—and the practicality of implementing this practice—is not as robust as we all would like,” says de Ferranti. “However, the ideal data may not be possible to collect, so we have to do our best to sort things out with other types of data.”
A method for change?
PCPs’ adherence to the recommendations is probably quite low, an assumption borne out by a study by de Ferranti and colleagues3. By comparing the NHLBI guidelines to U.S. census data from 2009, they estimated that “approximately 35 percent of patients would be eligible for lipid screening in any given year based on age,” but over a 16-year period, “clinicians ordered cholesterol testing at 3.4 percent of 10,159 health maintenance visits.”
De Ferranti attributes this to the busy PCP practices, with many competing demands. “In a condensed period of time, PCPs must already assess patients for several conditions,” she says. “Also, anecdotal accounts suggest that PCPs aren’t convinced that universal screening will truly uncover that many more at-risk patients.”
De Ferranti sees a role for subspecialists in educating PCPs about the importance or relevance of screening for particular disease states. For their part, the Preventive Cardiology Clinic and Boston Children’s Primary Care Center are implementing a lipid screening Standardized Clinical Assessment and Management Plan (SCAMP) for all patients of the appropriate ages and risk factors, with the goal of determining whether family history, height and weight may help determine a patient’s risk.
The SCAMP data they have collected to date challenge the NHLBI guidelines.
“There are several implicit assumptions underlying the guidelines, which must be valid for the guidelines to be valid,” de Ferranti explains. “Our preliminary data suggest that many of those assumptions may be wrong. Time and additional data will tell whether the guidelines hold up.”
1 Gillman MW and Daniels SR. “Is universal pediatric lipid screening justified?” JAMA. 2012; 307(3):259-60.
2 Psaty BM and Rivara FP. “Universal screening and drug treatment of dyslipidemia in children and adolescents.” JAMA. 2012; 307(3):257-8.
3 Vinci SR, et al. “Cholesterol testing among children and adolescents during health visits.” JAMA. 2014;311(17):1804-7