Cholesterol Testing Among Children and Adolescents During Health Visits

Abnormal lipid values occur in 1 in 5 US children and adolescents,¹ and are associated with cardiovascular disease in adulthood.² Universal pediatric lipid screening is advised by the National Heart, Lung, and Blood Institute (NHLBI)² for those aged 9 to 11 years and 17 to 21 years, in addition to the selective screening advised by the American Academy of Pediatrics (AAP) and the American Heart Association. In contrast, the US Preventive Services Task Force (USPSTF) did not find sufficient evidence to recommend any pediatric lipid screening.³

Despite substantial controversy,⁴ little is known about the frequency of cholesterol testing during pediatric health maintenance visits in the United States.⁵ We used the National Ambulatory Medical Care Survey (NAMCS)⁶ to examine (1) rates and correlates of testing and (2) trends in testing, including before and after the 2007 USPSTF and 2008 AAP cholesterol statements.

We performed a repeated cross-sectional analysis of cholesterol testing among patients aged 2 to 21 years seen by pediatric, internal medicine, or general or family medicine clinicians from 1995 through 2010 at health maintenance visits. The NAMCS generates nationally representative estimates via a multistage probability sample design using 112 geographic sampling units, clinicians within these units, and patient visits. Patient visits are assigned a weight equal to the inverse probability of that sampled visit. Data⁶ include patient demographics, type of visit (health maintenance, acute problem), physician specialty, practice setting, diagnoses, and medications (Table). Height and weight were recorded from 2005 through 2010 and were missing approximately 18% of the time. To ensure complete data on race, we used the NAMCS imputed race variable for 36% of the visits.

Using logistic regression models within a time series analysis, we examined trends in cholesterol testing before and after 2007-2008, the years the USPSTF and AAP released their statements. We modeled the trend in testing rate by including year (1995-2010, skipping 2007 and 2008) as a continuous variable, with 2 levels for 2009-2010. Using the model output, we compared (1) the trend in testing rates through 2009-2010 if the statements had no effect and (2) the actual testing rates. We also ran logistic regression models to examine associations of patient, clinician, and geographic characteristics with cholesterol testing, amalgamated across years. We used SAS version 9.3 (SAS Institute Inc). The Harvard Pilgrim Health Care institutional review board deemed this analysis exempt from review.

During the 16-year period, clinicians ordered cholesterol testing at 3.4% (95% CI, 3.1%-3.8%) of 10 159 health maintenance visits. Testing rates increased only slightly from 2.5% (95% CI, 0.4%-4.7%) in 1995 to 3.2% (95% CI, 2.0%-4.5%) in 2010 (P = .03 for unadjusted trend). The odds of testing did not increase following release of USPTSF and AAP statements (adjusted OR, 0.77 [95% CI, 0.36-1.65] for 2009-2010 vs 1995-2006) (Figure). Clinicians were more likely to order cholesterol testing for children who were older, taller, obese, black, or lived in the South or Northeast (Table). A sensitivity analysis for missing data on height and body mass index revealed consistent results.

Applying the most recent 2011 NHLBI guidelines to 2009 US census data, approximately 35% of patients would be eligible for lipid screening in any given year based on age (9-11 years and 17-21 years). In a nationally representative sample of ambulatory visits, we found low rates of cholesterol testing during pediatric health maintenance visits (3.4%) that increased only slightly between 1995 and 2010. Testing rates did not appear to increase after 2007-2008, perhaps reflecting the conflicting positions of the AAP and USPSTF.

Limitations of the study include an inability to discern screening from testing, and lack of data on family history and other risk factors that might affect testing decisions. Observed testing rates are probably an underestimate of screening due to the cross-sectional data, which could not reflect an individual patient’s previous or subsequent testing. To more accurately estimate screening rates, longitudinal data and more information on potential screening determinants such as family history are needed.

Corresponding Author: Sarah D. de Ferranti, MD, MPH, Boston Children’s Hospital, 300 Longwood Ave, Boston, MA 02115 (sarah.deferranti@cardio.chboston.org).

Author Contributions: Ms Rifas-Shiman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Vinci, Cheng, Mannix, Gillman, de Ferranti.

Acquisition, analysis, or interpretation of data: Vinci, Rifas-Shiman, Cheng, Mannix, de Ferranti.

Drafting of the manuscript: Vinci, Cheng, Mannix, de Ferranti.

Critical revision of the manuscript for important intellectual content: Vinci, Rifas-Shiman, Cheng, Gillman, de Ferranti.

Statistical analysis: Rifas-Shiman, Mannix.

Administrative, technical, or material support: Vinci.

Study supervision: Cheng, Gillman, de Ferranti.

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Gillman reported receiving royalties for Maternal Obesity (Cambridge University Press, 2012) and from UpToDate for a review topic on dietary fat. Dr de Ferranti reported receiving royalties from UpToDate for review topics on cholesterol screening and treatment in childhood; receiving funding from the Patient Centered Outcomes Research Institute on research related to cholesterol screening and treatment; and serving on the American Academy of Pediatrics Committee on Nutrition and the American Heart Association Atherosclerosis, Hypertension and Obesity in Youth Committee. No other disclosures were reported.