Effect of time standing up on orthostatic blood pressure change in the elderly: The J-SHIPP Study

Background:   Orthostatic dysregulation of blood pressure (BP) has been shown to be associated with an increased incidence of future cardiovascular disease, stroke and even mortality. To make a meaningful assessment of this association, we evaluated the effect of time elapsed after standing on any change in orthostatic BP.
Methods:   This study concerns 237 community-dwelling elderly people free from any history or symptoms of cardiovascular disease and not on medication. Basal BP was determined by averaging two determinations of supine BP measured with an automatic oscillometric BP recorder after resting for more than 10 min. Orthostatic change in BP was determined at 1 min and 3 min intervals after standing up.
Results:   The orthostatic change in systolic BP (ΔSBP) had a Gaussian distribution with a pivot at 1.2 ± 14 mmHg. The prevalence of subjects showing more than a 10% decrease in SBP at the 1-min interval was 14.3% (34 subjects). At the 3-min interval, 11 of them showed ΔSBP within ± 10%. However, another 17 subjects (7.2%) were newly diagnosed as having orthostatic hypotensive disorder. Similarly, 17.3% (41 cases) of subjects showed more than a 10% increase in ΔSBP at the 1-min interval. Among them, 22 (9.3%) subjects showed ΔSBP within ± 10% at the 3-min interval. However, another 20 (8.4%) subjects were newly diagnosed as having orthostatic hypertensive disorder.
Conclusion:   These results suggests that orthostatic dysregulation of BP could be evaluated by measuring at 1-min interval. However, if abnormal variation of BP was not observed, repeated measurement at 3 min would be necessary.