BP response to standing predicts masked hypertension

Young and middle-aged individuals with hyperreactivity to standing may have masked hypertension, according to a study.

Moreover, the likelihood for masked hypertension is fourfold higher in those with an orthostatic response >6.5 mm Hg and high urinary epinephrine, which indicates that sympathoadrenergic activity plays a role in the pathogenesis of masked hypertension.

A group of researchers analysed 1,078 individuals (mean age 33.2 years) with stage-1 untreated hypertension at baseline. Orthostatic response referred to the difference between six systolic blood pressure measurements in the orthostatic and supine postures. Individuals with a response >6.5 mm Hg (upper decile) were deemed hyperreactors.

The researchers measured 24-h ambulatory BP after 3 months of follow-up and classified participants as follows: normotensive (n=120), white-coat hypertensive (n=168), masked hypertensive (n=166), and sustained hypertensive (n=624). They also measured 24-h urinary epinephrine in 291 individuals.

After 3 months, orthostatic response was found to be independently associated with masked hypertension (p=0.001). Hyperreactors were 2.5-fold times more likely to have masked hypertension (95 percent confidence interval [CI], 1.5‒4.0; p<0.001).

Among participants stratified according to orthostatic response and urinary epinephrine, masked hypertension was 4.2-fold times more likely in hyperreactors with epinephrine above the median (95 percent CI, 1.8‒9.9; p=0.001) and 2.6-fold higher in those with epinephrine below the median (95 percent CI, 0.9‒7.3; p=0.069).

Cross-sectional analysis after 3 months confirmed the association of orthostatic response with masked hypertension (p<0.001).