Scientists have found that millions of people have their blood pressure measured incorrectly
Researchers analyzed the extent to which the procedure for measuring blood pressure in U.S. medical centers complies with the recommendations of the Heart Association. It turned out that doctors practically do not follow the rules, which leads to skewed results. As a result, "millions of people" take medications incorrectly.Hypertension is the leading risk factor for cardiovascular disease in the world. Accurate measurement is critical to both identifying risk in patients and prescribing effective treatment.
To improve treatment outcomes for patients in general and people with chronic diseases, especially cardiovascular diseases, BP should be measured according to certain rules. These have been developed by the American Heart Association.
For example, the health care professional must find a cuff that is the right size and must not have any clothing underneath. No talking is allowed during the measurement. The patient should sit in a chair with their feet on the floor, resting on the back of the chair and holding the arm with the blood pressure cuff at heart level.
But many medics measure blood pressure with the patient sitting on an exam table, leaving their legs dangling and their back and arms unsupported.
Researchers from Ohio State University (USA) compared BP readings obtained by strict adherence to the published AHA guidelines with those obtained by conventional (for many healthcare providers) methods of fixing BP. Specifically, they evaluated the effect on BP of failure to provide proper foot positioning on the floor, back support, and hand cuff support at heart level. The results are published in eClinicalMedicine.
Participants were recruited in the fall of 2022 from patients and staff in the outpatient department at The Ohio State University Wexner Medical Center in Columbus.
A total of 150 people were included in the randomized, three-group clinical trial with a cross-over design. In one group (48 participants), BP measurements were performed on a fixed-height examination table and then on an exam chair with an adjustable position.
In a second group (49 participants), the same readings were taken in reverse order. In the third group (53), both sets of readings were taken on the exam chair. The participants rested before each data collection.
The scientists combined the results. The average of the three measurements taken on the table was compared to the average of the measurements taken on the chair.
It turned out that the systolic blood pressure measured in the person on the couch was seven millimeters of mercury column higher than the person sitting in the chair, while the diastolic pressure was 4.5 millimeters of mercury column higher.
According to the study authors, this difference is enough to misclassify millions of people as having hypertension, when in fact their blood pressure remains within the normal range. So, hypertension medications can often be prescribed unnecessarily, putting people at risk for excessively low blood pressure.
It's worth noting that a lot of people around the world measure their own blood pressure, at home. Obviously, the accuracy of the values obtained in this way cannot be higher than the average of doctors from the work described above. Consequently, the habit of relying on incorrectly measured blood pressure (followed by taking blood pressure-lowering pills) should affect at least millions of people around the world and outside the medical community.