Prevalence and Clinical Significance of Isolated Ambulatory Hypertension in Young Subjects Screened for Stage 1 Hypertension

Abstract

Abstract-Little is known about the clinical significance of isolated ambulatory hypertension, a condition characterized by low office but elevated ambulatory blood pressure. This study aimed to investigate the prevalence and the predictive value of isolated ambulatory hypertension diagnosed after 3 months of observation for the development of sustained hypertension within a cohort of 871 never-treated stage-1 hypertensive subjects. The study end point was progression to more severe hypertension and need of antihypertensive medication. In 244 subjects (28%), clinic blood pressure declined to Ͻ140/90 mm Hg after 3 months. Of these, 124 (14.2% of total) had low clinic and ambulatory blood pressures after 3 months (nonhypertensive subjects), whereas 120 subjects (13.8% of total) showed low clinic but elevated ambulatory blood pressure (isolated ambulatory hypertension). During the 6 years of observation, the number of end points based on multiple clinic blood pressure readings progressively increased from the nonhypertensive subjects (19%) to the subjects with isolated ambulatory hypertension (35%) and to the subjects with high clinic and high ambulatory blood pressures (65%, PϽ0.0001). In an adjusted proportional hazard model, isolated ambulatory hypertension status was associated with a 2.2 (Pϭ0.02) increase in the risk of reaching the end point in comparison with the nonhypertensive subjects. Final ambulatory systolic blood pressure was also higher in the former than the latter (Pϭ0.03). Our results indicate that among subjects screened for stage 1 hypertension, individuals with isolated ambulatory hypertension after 3 months of observation have increased risk of developing sustained hypertension in later life compared with subjects in whom both clinic and ambulatory blood pressures are normal.

Masked hypertension: A common but insidious presentation of hypertension

“…The damage associated with MH is not limited to adults, and has been reported in children and youths (17)(18)(19), in whom the finding of MH may suggest a prehypertensive state (11).…”

“…Whether young age is a consistent feature of MH is a matter of some disagreement (11,14,24,25), with some reports not finding this association.…”

Unmasking Hypertension

“…In adults, there seems to be little doubt but that masked hypertension confers an increased cardiovascular risk. First, adults with masked hypertension are at increased risk for sustained hypertension, 9,12 and this is also the case with the children and adolescents in the study of Lurbe et al in whom nearly half had persistent masked hypertension or sustained hypertension when followed-up over 3 years. 13 Second, adult subjects with masked hypertension have increased target organ involvement as denoted by left ventricular mass and carotid atherosclerosis.…”

“…In adults regression to the mean, increased variability, smoking, alcohol drinking, sedentary habits, greater reactivity to daily life stressors, and standing have all been suggested as possible factors. 9,10,12 In youthful subjects, the blood pressure reaction to standing, which is more pronounced in young individuals and is known to affect average daytime blood pressure and physical activity, neither of which were assessed in the study by Lerbe et al, could have been relevant in inducing masked hypertension.…”

“…Children with masked hypertension tend to have a higher ambulatory pulse rate than normotensive subjects, 13 which may indicate greater reactivity to the stressors of daily life or to the effect of standing, which has also been shown to be associated with masked hypertension in adults. 12 Children with masked hypertension also have higher nocturnal blood pressure than normotensive subjects, suggesting that future study might focus on nighttime blood pressure, which, being less influenced by daily activity, might provide a more reproducible profile of masked hypertension. The detection of left ventricular hypertrophy in children or adults without an obvious cause is another indication for ABPM to exclude masked hypertension.…”