Screening for Elevated Blood Pressure in Children and Adolescents. A Critical Appraisal

Arnaud Chiolero, MD, PhD; Pascal Bovet, MD, MPH; Gilles Paradis, MD, MSc

Although screening for elevated blood pressure (BP) in adults is beneficial, evidence of its beneficial effects in children is not clear. Elevated BP in children is associated with atherosclerosis early in life and tracks across the life course. However, because of the high variability in BP, tracking is weak, and having an elevated BP in childhood has a low predictive value for having elevated BP later in life. The absolute risk of cardiovascular diseases associated with a given level of BP in childhood and the long-term effect of treatment beginning in childhood are not known. No study has experimentally evaluated the benefits and harm of BP screening in children. One modeling study indicates that BP screen-and-treat strategies in adolescents are moderately cost-effective but less cost-effective than population-wide interventions to decrease BP for the reduction of coronary heart diseases. The US National Heart, Lung, and Blood Institute and the European Society of Hypertension recommend that children 3 years of age and older have their BP measured during every health care visit. According to the US Preventive Services Task Force, there is no sufficient evidence to recommend for or against screening, but their recommendations have to be updated. Whether the benefits of universal BP screening in children outweigh the harm has to be determined. Studies are needed to assess the absolute risk of cardiovascular diseases associated with elevated BP in childhood, to evaluate how to simplify the identification of elevated BP, to evaluate the long-term benefits and harm of treatment beginning in childhood, and to compare universal and targeted screening strategies.
Hypertension is a major risk factor for cardiovascular diseases (CVDs). Worldwide, 7.1 million deaths (13% of the global total) are due to elevated blood pressure (BP) in adults every year.1
Until recently, hypertension was rarely searched for or diagnosed in children and adolescents. However, the approach toward elevated BP in childhood is changing because of the growing evidence that elevated BP in youth has detrimental lifelong cardiovascular effects.2
The BP level in childhood tracks to the BP level in adulthood, and children with elevated BP have a higher probability of developing hypertension as adults than do children with low BP.3 This BP tracking is a major argument for being concerned with elevated BP early in life; since BP tracks, prevention and treatment of elevated BP early in life can result in a lifelong reduction of BP and of its associated conditions.
Furthermore, elevated BP in childhood is associated with cardiac left ventricular hypertrophy4 and a thickening of the carotid intima-media, a surrogate marker for atherosclerosis and a strong predictor of CVD.5 Raised fibrous plaques of atherosclerosis have been observed in the aorta of children as young as 8 years of age, and the plaque extent has been shown to be associated with BP levels.6
Another reason for the interest in elevated BP in childhood is the increase in the prevalence of obesity. Because obesity is associated with elevated BP at all ages including childhood,79 it is often assumed that the prevalence of hypertension has increased in youth in the last decades,1011although such trends have not been observed in all populations.1215 Finally, although the clinical approach to the prevention of CVD relies on the identification and treatment of risk factors starting in mid-adulthood, a life-course approach to prevent the development of risk factors starting in childhood offers new avenues for the prevention of hypertension and CVD.1617
In view of this evidence, universal BP screening beginning in childhood is advocated.1820Undiagnosed elevated BP has become a matter of concern in children.2122 Screening for elevated BP may help identify children at increased risk of hypertension and CVD later in life and for whom early treatment could be beneficial.23 Nevertheless, although there is strong evidence that screening for hypertension is beneficial for adults,2425 it is unclear whether screening is beneficial for children. Our aim is to critically appraise the evidence and recommendations regarding the screening for elevated BP in children and adolescents.