Separate studies related to hypertension send cautionary messages about smartphone-connected blood pressure cuffs and the quality of videos that patients see online about hypertension.
In one study, readings from three smartphone-connected blood pressure cuffs produced a wide range of measurements in an individual patient, raising questions about the apps’ accuracy even though those brands of devices previously had been validated. A separate survey of videos about hypertension posted on YouTube found lots of misleading information, often in the most popular videos.
Investigators presented the studies at the annual meeting of the American Society of Hypertension in New York.
Dr. Clarence Grim
Dr. Clarence E. Grim, an endocrinologist and former professor of medicine at the Medical College of Wisconsin, Milwaukee, tested three devices that connect to iPhones to enable patients to measure their blood pressure, store the results, and send the readings to others. Quality validation studies have been published for all three using international hypertension protocols, he said, and each passed muster with the Food and Drug Administration.
In multiple sessions over a 3-month period, Dr. Grim took his own blood pressure five times per session after being seated for 5 minutes, using the iHealth BP3 upper arm cuff, the iHealth BP7 wrist cuff, or the Withings upper arm blood pressure monitor. For reference measurements, he used a Tycos TR-2 Home Aneroid with an attached stethoscope for auscultatory measurements, validated against a mercury manometer.
In comparison with a reference systolic pressure of 138 using the auscultatory method, measurements using the iHealth arm device ranged from 127 to 158 mm Hg, with an average error of 8 mm Hg higher than the reference pressure. Measurements using the iHealth wrist device ranged from 123 to 164 mm Hg, with an average error of 13 mm Hg higher than the reference. Measurements using the Withings device ranged from 126 to 159 mm Hg. Although the average pressure with the Withings device did not differ significantly from the reference pressure, when there were errors, they tended to be large, he reported in an interview.
Diastolic pressure readings similarly were "not acceptable" due to wide variation, Dr. Grim said. With a reference diastolic pressure of 88 mm Hg, readings from either the iHealth arm device or the Withings device ranged from 80 to 100 mm Hg. With a reference diastolic pressure of 92 mm Hg, the iHealth wrist device readings ranged from 92 to 110 mm Hg.
No one should rely on a single blood pressure reading whether using a home device or the auscultatory method, Dr. Grim said. He’d prefer that automated devices be set to take three to five readings at a session. Anyone who chooses to use one of the three devices he tested should have a clinician check that the device is accurate on them, but the best way to test this is not clear, he added.
"I still have not found an automatic blood pressure device that is as accurate as auscultatory readings on me," he said.
Dr. Nilay Kumar, a hospitalist for Cambridge (Mass.) Health Alliance, separately reported at the meeting that he searched the popular video-sharing website YouTube using the terms "hypertension" and "high blood pressure." He and his associates analyzed English-language videos from the first 10 pages of search results for each term, comprising 209 videos of the 361,200 possible search results, and designated each video as useful, misleading, or a video of personal experiences.
While most were deemed useful (63%), 33% were misleading, and 4% represented patients’ personal experiences with hypertension (J. Am. Soc. Hypertens. 2014;8:e14-e15).
Cumulatively, the videos had been viewed more than 5.6 million times. Their usefulness did not correlate with the number of views per day, the number of "likes" or "dislikes" indicated by viewers, or comments left on the sites, he said in an e-mail interview. In fact, misleading videos had the highest numbers of views per day. Misleading videos were more likely to include advertisements for products for sale (52%), and 70% of misleading videos contained coverage of alternative treatments, often for products that are not recommended by American Heart Association guidelines.
The source of the video, however, did predict its usefulness. "Patients should trust videos from authoritative sources such as universities, professional organizations, and health information websites," Dr. Kumar said.
Dr. Grim and Dr. Kumar reported having no financial disclosures.
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