Baseline clinic heart rate and heart rate changes during the first few months of follow-up are independent predictors of the development of sustained hypertension in young persons screened for stage 1 hypertension.

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.

These data indicate that a condition characterized by sympathetic predominance may favour the development of sustained hypertension and hypercholesterolemia early in life, and lead to increased susceptibility to vascular complications. They further indicate that the increased white-coat effect is not an innocent phenomenon.

These results indicate that forearm blood pressure measurement markedly overestimates upper arm blood pressure and that the between-site difference may vary from subject to subject. Wrist blood pressure measurement is not a valid alternative to traditional measurement at the arm and its use should be discouraged.

Indexes of arterial distensibility are impaired in the white-coat hypertensive group and similar to those in the sustained hypertensive group, indicating that early changes in the arterial wall can occur in white-coat hypertension. This may account for the higher risk of stroke that has been described in this condition.