Hypertension often goes undiagnosed in children (JW Pediatr Adolesc Med Aug 29 2007). An important question is the extent to which sporadically elevated blood pressure (BP) persists in adolescents. In this study, investigators examined the persistence of hypertension (systolic or diastolic BP
95th percentile) or prehypertension (systolic or diastolic BP 
90th percentile or 
120/80 mm Hg but lower than the threshold for hypertension) in 8533 adolescents whose BP was measured at age 13, 14, or 15 and repeated 2 and 4 years later.Initially, 67% of boys and 77% of girls were normotensive; most remained normotensive at 2 years, but 31% and 12% were prehypertensive at 2 years, and 5% and 4% had developed hypertension. Among boys and girls initially classified as prehypertensive (21% and 13%, respectively), 50% and 24% remained prehypertensive at 2 years, and 14% and 12% had developed hypertension. Among those who were initially hypertensive (11% of boys and 10% of girls), 31% and 26% remained hypertensive at 2 years and 47% and 26% were prehypertensive. Among both boys and girls, changes at 4 years were similar to those at 2 years and systolic BP was associated significantly with weight gain.
Comment: Although these data were based on single BP measurements and probably overestimate the prevalence of elevated BP in adolescents, analysis of follow-up measurements suggests that about 7% of prehypertensive adolescents become hypertensive annually. The message is that BP should be measured in adolescents at every healthcare visit.
— Howard Bauchner, MD
Published in Journal Watch Pediatrics and Adolescent Medicine August 13, 2008