An Alternative View of Childhood Blood Pressure Screening

The United States Preventive Services Task Force (USPSTF) has issued an I statement (insufficient evidence) regarding the benefits and harms of childhood blood pressure (BP) screening.1,2 This outcome, which is the same conclusion as their analysis of childhood BP screening in 2013,3 is expected given how the key questions were framed and the analysis performed. However, what is the best approach to assess whether childhood BP measurement is associated with adult cardiovascular disease (CVD) or whether treatment of high BP in childhood is associated with reducing the burden of adult CVD? The best evidence to address these questions would be randomized clinical trials comparing screening vs no screening and treatment vs no treatment. Given the recommendations of the American Academy of Pediatrics (AAP),4 European Society of Hypertension,5 and other organizations that screening BP measurement should be performed and persistent hypertension treated in children and adolescents, clinical trials that directly address these questions are likely infeasible. The required length of follow-up, likely 5 or 6 decades, is an additional barrier. The questions must be reframed. Perhaps the appropriate question to ask is: does BP measurement in childhood identify children and adolescents who already have markers of CVD or who are at risk of developing them as adults? Such youth so identified would then be candidates for measures designed to prevent progression of their cardiovascular risk factors to established CVD. Reframing the question in this way maintains a focus on prevention while avoiding the requirement that the only acceptable outcome is prevention of CVD events in adulthood, such as stroke, myocardial infarction, or death. What then are the available data that would address the reframed question? Cross-sectional studies can establish the association between BP levels and markers of cardiovascular risk that are already present. The body of such evidence has been recently strengthened by several publications from the multicenter Study of High Blood Pressure in Pediatrics: Adult Hypertension Onset in Youth (SHIP-AHOY), which enrolled approximately 400 adolescents with office BP values ranging from below the 75th percentile to stage 1 hypertension and then carefully performed additional assessments to examine potential cardiovascular risk, including 24-hour ambulatory BP monitoring, metabolic testing, and examinations of cardiac structure and function, vascular function, and cognition.6 The SHIP-AHOY results have demonstrated that increased left ventricular mass can be demonstrated at BP levels currently classified as normotensive and that abnormal left ventricular function can be seen at similar BP levels.7,8 Furthermore, they have established a substantial association between an abnormal metabolic phenotype and several forms of target-organ damage associated with high BP.9 These multicenter data reinforce prior singlecenter studies that demonstrated the adverse consequences associated with high BP in children and adolescents10 and set the stage for the institution of measures designed to reverse target-organ damage and reduce cardiovascular risk in youth.4,5 Given the lack of prospective clinical trials, analysis of longitudinal cohort studies is the best available method for examining the potential association between current BP levels and future CVD.11,12 A recent publication from the International Childhood Cardiovascular Cohort Consortium13 showed that specific systolic BP levels in childhood were associated with increased adult carotid intima-media thickness, which is accepted as a surrogate marker of atherosclerosis. Other longitudinal cohort studies have demonstrated meaningful associations between childhood BP levels + Author Audio Interview + Related article at jama.com