Blood pressure reactivity and bias vary with age in a comparison of traditional and automated methods of measurement.

This study examined the effects of initial-reading reactivity and measurement methods of blood pressure across different age groups. Subjects were men and women (n = 132), 17 to 96 years of age. Two measurements were obtained from each subject, with a 1-min interval between trials. Each trial consisted of concurrent measurements from each arm, using a standard mercury manometer and an automated blood pressure monitor for use at home. A double-blind control procedure was used. Significant effects were obtained for age (younger, middle, and older age groups), method by trial and age by trial. The blood pressure reactivity and the effect of observer bias varied across age groups. The results support the hypotheses that blood pressure readings decline across trials; that observer bias using traditional methods is sufficient to mask this decline; and that the extent of reactivity and subsequent decline is dependent on age or an age-related increase in blood pressure. Implications of these findings for the use of automated monitoring instruments designed for use at home are discussed.