Low blood pressure

Readers, especially older people, may be interested in this article about unstable blood pressure and dizziness. (Orthostatic = standing upright)

Orthostatic Hypotension in Older Adults

The prevalence was surprisingly high.

Orthostatic hypotension is common in older adults, particularly among those taking hypotensive medications and those with diseases associated with autonomic dysfunction (e.g., diabetes, Parkinson disease). In this study from Ireland, researchers used a continuous noninvasive blood pressure (BP) monitoring device to measure orthostatic change on a single occasion in 442 community-dwelling, older adults (mean age, 72).

Mean baseline supine systolic BP (SBP) was 160 mm Hg. The changes from supine to standing SBP conformed to three general patterns:

"Small drop, fast overrecovery" (25% of participants): mean SBP drop within 30 seconds, 16 mm Hg; quick recovery exceeding baseline SBP at 30 seconds
"Medium drop, slow recovery" (54% of participants): mean SBP drop within 30 seconds, 35 mm Hg; return to near-baseline SBP at 30 seconds and at 2 minutes
"Large drop, nonrecovery" (21% of participants): mean SBP drop within 30 seconds, 62 mm Hg; gradual but incomplete return to baseline SBP during 2 minutes of monitoring

Eighty-five participants met a previously published definition of "initial orthostatic hypotension" — a symptomatic SBP drop of >40 mm Hg within 15 seconds (Clin Sci (Lond) 2007; 112:157). These elders, compared with other participants, were more likely to have fallen recently (25% vs. 10%), to be taking >4 medications (54% vs. 39%), and to meet criteria for frailty or prefrailty (71% vs. 52%).

Comment: Substantial orthostatic hypotension was surprisingly common among these older people. Many had "initial orthostatic hypotension," an entity characterized by an almost immediate drop in BP that can elude detection when clinicians use conventional measuring devices. Clinically important orthostatic hypotension — both initial and delayed — almost certainly is underrecognized among older patients. Clinicians should routinely ask older patients about postural dizziness, check for orthostatic changes during office visits, and adjust medications and make other recommendations that mitigate postural BP changes.

— Allan S. Brett, MD

Published in Journal Watch General Medicine April 28, 201