Image: A new study recommends revising guidelines for orthostatic hypotension assessment (Photo courtesy of iStock).
Researchers have found that measuring blood pressure to test for the presence of orthostatic hypotension (OH; a form of low blood pressure) should be performed within one minute of standing after a person has been lying down, instead of three minutes after.
“Our findings suggest that a blood pressure assessment within the first minute is a better way to assess health risks due to OH and that waiting three minutes might miss at-risk status,” said paper first-author Stephen Juraschek, MD, PhD, of Johns Hopkins University School of Medicine (Baltimore, MD, USA).
OH (sometimes called postural hypotension) is common among older adults, marked by dizziness, lightheadedness, and even fainting when they stand up. Although sometimes related to medication side effects, anemia, or dehydration, OH in many cases has unknown causes. It may increase risk of falls and strokes, both of which can be lethal.
Clinically, a person is diagnosed with OH when systolic blood pressure drops by at least 20 mmHg during transition from lying down to standing up, or when diastolic blood pressure drops by at least 10mmHg within three minutes after standing. While a healthy person’s blood pressure will return to their baseline readings almost immediately after such a test, blood pressure for people with OH will linger at lower values for a while.
The current three-minute threshold was implemented after a review of studies and a consensus statement from the American Academy of Neurology in the late 1990s. This statement was later reiterated in 2011. In practice, however, clinicians often do not wait the recommended 3 minutes to measure blood pressure due to time constraints.
To learn whether waiting or not waiting for the three-minute threshold made any significant difference in risk assessment, Dr. Juraschek and his team analyzed blood pressure data already gathered on over 15,000 people ages 45-64 during the Atherosclerosis Risk in Communities Study (ARIC; conducted during 1987-1989). They focused on data taken from 11,429 participants who had at least 4 measurements testing for OH over time, and looked for links between measurement times and adverse events – falls, fractures, fainting, and car crashes. They also looked for association between time of measurement and death. Of the participants, 54% were women and 26% were black, with an average age of 54 years. Nearly 10% of participants self-reported a history of dizziness upon standing.
The researchers found that measurements taken within 30 seconds of standing were associated with the highest rates per 1,000 person-years of fracture (18.9), fainting (17.0), and death (31.4). Measurements taken within 1 minute were associated with the highest rate of falls (13.2 per 1,000 person-years) and car crashes (2.5). Measurements taken within 30 seconds were associated with the greatest proportion, 13.5%, of self-reported dizziness.
The findings support the idea that OH assessments performed within one minute of standing are most strongly related to self-reported dizziness and individual adverse outcomes: “If someone comes into the clinic with dizziness, we try to assess his/her risk of falling or other consequences of dizziness in the future,” said Dr. Juraschek, “These results show that assessing OH within the first minute not only is OK, but also makes a lot of sense because it’s more predictive of future falls.”
Current treatments for chronic OH include physical therapy to improve balance, lifestyle changes including drinking more fluid and eating smaller meals, altering the environment (such as using grip bars), coaching patients how to safely stand up, and changing or stopping certain medications.
The study, by Juraschek S et al, was published July 24, 2017, in the journal JAMA Internal Medicine.
Johns Hopkins University School of Medicine